Curriculum Training. Suspension Systems. Air Suspension Systems. Technical Training LRE 077_1 en 05/2005 L 480

Transcription

1 Curriculum Training Suspension Systems Air Suspension Systems Technical Training LRE 077_1 en 05/2005 L 480

2 To the best of our knowledge, the illustrations, technical information, data and descriptions in this issue were correct at the time of going to print. The right to change prices, specifications, equipment and maintenance instructions at any time without notice is reserved as part of our policy of continuous development and improvement for the benefit of our customers. No part of this publication may be reproduced, stored in a data processing system or transmitted in any form, electronic, mechanical, photocopy, recording, translation or by any other means without prior permission of Premier Automotive Group. No liability can be accepted for any inaccuracies in this publication, although every possible care has been taken to make it as complete and accurate as possible. Copyright 2005

3 Preface Publication Notes: Please remember that our training literature has been prepared for TRAINING PURPOSES only. Repairs and adjustments MUST always be carried out according to the instructions and specifications in the workshop literature. Please make full use of the training offered by Technical Training to gain extensive knowledge of both theory and practice. Technical Training (G538468) 1

4 Table of Contents PAGE Preface... 1 At a glance... Air Suspension Introduction... Land Rover Systems Lesson 1 General Information Objectives... Range Rover (LP)... System Description Range Rover (LM)... System Description Discovery Series II... System Description Discovery 3 / LR3... System Description MY Range Rover (LM)... System Description Technical Training

5 Table of Contents Lesson 2 Component Description Objectives... Range Rover (LP)... Components Review... Component Location Range Rover (LM)... Components Review... Component Location Discovery II... Component Review... Component Location Discovery 3 / LR3... Component Review... Component Location MY Range Rover (LM) Technical Training 3

6 Table of Contents Lesson 3 Principles of Operation Objectives... Range Rover (LP)... System Control Range Rover (LM)... System Control Discovery Series II... System Control Discovery 3 / LR3... System Control MY Range Rover (LM)... System Control Lesson 4 Diagnostics Objectives... Range Rover (LP)... System Checks Range Rover (LM)... System Checks Discovery Series II... Discovery 3 / LR MY Range Rover (LM)... System Checks Technical Training

7 Table of Contents Lesson 5 Service Procedures Objectives... Service Information... Service Bulletins... Height Setting Tools Technical Training 5

8 Safety and Precautions Workshop safety This page highlights the general observations expected whilst attending this training programme, and its continuation upon returning to your place of work. General Whilst working on all vehicles, the following items where available should always be used: Wing covers Seat covers Floor protection Optional items: Steering wheel cover Park brake lever cover Door grab handle protection Safety All precautions must be taken and observed at all times, to prevent injury or damage to the following: Yourself Customer's property Workshop equipment Work place colleagues Operating guidelines Whilst using any piece of workshop equipment: The manufacturer's guidelines and warning labels must be followed. This will ensure correct use and application at all times. Seek the necessary advice or training where equipment usage is unclear. Chemicals, Oils and Solvents Follow all manufacturer's warnings and labels, also take into account local disposal regulations when working with chemicals, oils or solvents. Ensure that all risks are completely minimised. Make sure that all protective items of clothing are worn where required e.g. Eye protection Gloves Overalls Footwear System capping Upon disconnecting components from a system, take all precautions necessary to prevent system contamination or environmental leakage. Fit relevant plugs or caps i.e. to pipes, unions and component orifices etc. Updates Keep abreast of all relevant changes that effect your role within the dealership, by monitoring all factory issued documentation. Driving Operating vehicle features, such as ICE, mobile phones and CD player equipment etc., can cause a momentary distraction whilst driving. Follow all road traffic regulations as written in the Highway Code, when operating vehicle systems or using diagnostic equipment whilst on the move. Mobile diagnostic equipment operation, may require the use of an assistant. 6

9 Introduction At a glance Air Suspension Introduction The first patents for air springs came about in the early 1900's to reduce the amount of road shock and vibration transmitted into the vehicle. Air springs were initially leather diaphragms used as buggy springs. Convoluted air springs were developed and patented in the 1930's. Development of the first air springs were always intended for used in automotive suspension applications. The first major success for the air spring application was as a transit bus spring. A small industrial market began to grow in the early 1940's. By the mid 1950's, air springs were finally being used in an automotive suspension system as intended. Later in that same decade, the truck and trailer segment began to grow. Land Rover Systems Air springs were introduced as an option on a Land Rover product in 1992 for the top models of the 'Classic' Range Rover. By 1994 it had become a standard feature on all Range Rovers models. In 1998, rear air suspension was seen for the first time as an option on Discovery Series II with the introduction of the Self Leveling Suspension (SLS) system. Discovery 3 / LR3 was upgraded to full four corner air suspension system for higher specification vehicles at 2005MY. Range Rover Sport with four corner air suspension was introduced using a modified carry over version of the Discovery 3 / LR3 air suspension system at MY. Range Rover also received a slightly modified version of the Discovery 3 / LR3 air suspension system at 2006MY. Today, air springs are to be found on a large proportion of off-road luxury vehicles, plus many other premium brands. Air suspension systems use air springs instead of conventional steel springs. The air spring system has computer operated vents on the air spring with suspension sensors and an on-board air compressor. This allows the system to maintain vehicle ride height and vary the suspension characteristics according to the driving environment. Air filled rubber or elastomer air bags are pressurized to provide vehicle support to the suspension. Technical Training (G538468) 7

10 Lesson 1 General Information Objectives On completing this lesson, you will be able to: Describe the features and benefits of air suspension. Explain the different air suspension modes of operation. Technical Training (G538470) 9

11 Range Rover (LP) Lesson 1 General Information RANGE ROVER (LP) System Description Range Rover (LP) All Range Rover (LP) derivatives feature a four corner electronic air suspension system. Electronic Air Suspension (EAS) The Range Rover (LP) Electronic Air Suspension (EAS) system is already well established. However, progressive development since introduction has resulted in added features to improve control and operation of the system. Air springs provide a soft and comfortable feel to the ride and handling of the vehicle. The use of a microprocessor to control the system exploits the advantages of air suspension even further. Benefits Air suspension systems provide a near constant ride frequency under all load conditions. This results in: Improved ride quality Consistency in ride quality Constant ride height Improved headlamp leveling 10 (G538469) Technical Training

12 Lesson 1 General Information Range Rover (LP) Height Settings The system provides five ride height settings, plus self leveling. Each setting is automatically maintained at the correct height by the system with minimum driver involvement. Vehicle height is sensed by four rotary potentiometer type sensors. Height information from each sensor signals the ECU to adjust each air spring by switching the solenoid valves to increase or decrease air. The five different height settings are as follows: Extended ride height High profile Standard ride height Low profile Access/Crawl mode Ride Heights All the height settings apart from standard height deviate either up or down from the standard height setting. Extended = 70 mm above standard ride height (setting is not driver selectable) High is 40 mm above standard ride height Standard ride height is designated as zero (0 mm), this is the datum point used for all height reference. Low is 25 mm below standard ride height (automatic and not driver selectable) Access is 65 mm below standard ride height Crawl mode is access ride height available up to 20 mph (32 km/h) Self Leveling Description On a coil sprung suspension vehicle the effect of adding weight results in the vehicle leaning. With an air suspension system the systems ECU detects any body lean and automatically compensates. The vehicle will self level to the lowest corner height for 20 seconds each time the driver exits the vehicle and closes all the doors. The system checks the vehicle height every six hours and makes minor corrections, not exceeding 8 mm. WARNINGS: Before commencing work which requires access to the underside or wheel arches of the vehicle, the suspension must be allowed to re-level. Re-leveling is achieved by opening and closing any of the doors, while all other doors and tailgate remain closed with the ignition off. The Electronic Air Suspension (EAS) must be set in 'High Lock' mode using the T4 diagnostic equipment during any work that does not require chassis to axle displacement. This will hold the suspension in the extended profile height position until reset by the T4 diagnostic equipment. This renders the vehicle safe to work on by preventing system inputs, e.g. pressing the height control switch. CAUTION: The underside of the vehicle must be kept clear of obstacles whilst the vehicle is parked, as self leveling may result in reduced vehicle trim height. If the vehicle is parked on uneven ground or with a wheel or wheels on the kerb, the system will lower the vehicle to the lowest spring height. When unloading through the tailgate, the system will self level to compensate for the decreased load after tailgate closure. The lean can either be front to rear or side to side unless the weight is evenly spread. Technical Training (G538469) 11

13 Range Rover (LM) Lesson 1 General Information RANGE ROVER (LM) System Description Range Rover (LM) All Range Rover (LM) derivatives feature a four corner electronic air suspension system. Air Suspension Description The main function of the four corner air suspension system is to maintain the vehicle at the correct ride height, irrespective of vehicle load. Additionally, the system allows the driver to request ride height changes to improve the off-road performance or ease of access or loading. The system automatically adjusts ride height settings to improve vehicle handling and dynamics when road speed increases or decreases. System Height Settings The system provides four ride height settings: Standard (used during most driving conditions) Off-Road (highest of the four settings, and raises the front of the vehicle 60 mm and the rear 50 mm) Motorway (lowers the vehicle by 20 mm to improve high speed handling) Access (lowers the vehicle by 40 mm when stationary or moving at very low speeds in order to improve access to the vehicle) 12 (G538469) Technical Training

14 Lesson 1 General Information Range Rover (LM) System Inhibits The system will temporarily inhibit height adjustments when the vehicle is subject to cornering, heavy acceleration or heavy braking. The inhibit function prevents unsettling of the vehicle by reducing the effective spring rates. Height changes are also inhibited for safety reasons, when a door is opened and the vehicle is stationary for example. Air Suspension ECU The air suspension system fitted to Range Rover is controlled by an ECU located behind the passenger side of the fascia. The ECU monitors the height of each corner of the vehicle by four height sensors, which are mounted in-board of each road wheel. On-board diagnostics perform health checks on the air suspension system. If faults are detected, codes are stored in the ECU and can be retrieved using the T4 diagnostic equipment (not the hand held unit). Technical Training (G538469) 13

15 Discovery Series II Lesson 1 General Information DISCOVERY SERIES II System Description Discovery Series II Self Leveling Suspension (SLS) An optional feature for Discovery Series II is Self Leveling Suspension system (SLS). This incorporates air springs for the rear axle with conventional springs fitted to the front of the vehicle. Operates under control of the Self Leveling / Anti Lock Brakes (SLABS) ECU. System used during most driving conditions and also provides the vehicle with additional height when traveling off-road. Additional height is not driver selectable and will operate when a grounded chassis is sensed. Vehicle Ride Heights Standard Ride Height Mode: Used during most driving condition Off-Road Ride Height Mode: Provides the vehicle with additional height when traveling off-road Extended Ride Height Mode: Operates under direct control of the SLABS ECU It is not a driver selectable mode Operates when a grounded chassis is sensed 14 (G538469) Technical Training

16 Lesson 1 General Information Discovery Series II Transportation Mode: To be used whenever the vehicle is lashed down by its chassis frame for transportation purposes Technical Training (G538469) 15

17 Discovery 3 / LR3 Lesson 1 General Information DISCOVERY 3 / LR3 System Description Discovery 3 / LR3 System Description The dynamic suspension system is a four corner air suspension system which is fitted to higher specification vehicles in place of the conventional damper and coil spring suspension used on non-air suspension models. The dynamic suspension system is electronically controlled by an air suspension control module which controls the air supply unit, reacting to inputs from four height sensors and distributes air around the system via valve blocks. System Components The main air suspension system components are: Air suspension control module (Siemens) Air supply unit (Tokico) Four height sensors (AB electronics) Three valve block assemblies (Webber) Reservoir (NCJ) Air harness Four suspension air spring damper modules (Firestone) Height Control The four corner air suspension system maintains the vehicle height under all operating conditions by controlling the mass of air in the air springs. 16 (G538469) Technical Training

18 Lesson 1 General Information Discovery 3 / LR3 The air suspension control module uses signals from the four height sensors to maintain the correct suspension height. This is achieved by operating pneumatic control valves to increase or decrease the mass of air in the air spring damper modules. The air suspension system has three driver selectable, pre-determined ride heights. A driver interface indicates the selected ride height and direction of movement. Additional information is also relayed to the driver via the instrument cluster message center (where fitted) and by audible warnings also transmitted by the instrument cluster. Height changes can only be made when the engine is running and the driver and passenger doors are closed. Access height can be selected with the engine not running, within 40 seconds of moving the ignition switch to the off position provided the driver's door has not been opened in this time. The air suspension can be controlled manually by the driver using a switch on the center console to select the required height change. Technical Training (G538469) 17

19 2006MY Range Rover (LM) Lesson 1 General Information 2006MY Range Rover (LM) System Description Range Rover (LM) The air suspension system is a four corner air suspension system which is fitted to all Range Rover 2006MY variants. The system is electronically controlled by an air suspension control module which controls the air supply unit, reacts to inputs from four height sensors and distributes air around the system via valve blocks. System Components The main air suspension system components are: Air suspension control module Air supply unit Four height sensors Three valve block assemblies Reservoir Air harness Two front struts incorporating air spring damper modules Two rear air spring damper modules. Height Control The four corner air suspension system maintains the vehicle height under all operating conditions by controlling the mass of air in the air springs. 18 (G538469) Technical Training

20 Lesson 1 General Information 2006MY Range Rover (LM) The air suspension control module uses signals from the four height sensors to maintain the correct suspension height, irrespective of vehicle load. Additionally, the system allows the driver to request ride height changes to improve off-road performance or ease access or loading. The system automatically adjusts the ride height to improve the vehicle handling and dynamics when speed increases or decreases. This is achieved by operating pneumatic control valves to increase or decrease the mass of air in the air springs. The air suspension system has three driver selectable, pre-determined ride heights and an automated high speed ride height. A driver interface indicates the selected ride height and height change movement. Additional information is also relayed to the driver via the instrument cluster message center and by audible warnings also transmitted by the instrument cluster. Most height changes can only be made when the engine is running and the driver's and passenger doors are closed. Access height can be selected with the engine not running, within 40 seconds of moving the ignition switch to the off position provided the driver's door has not been opened in this time. The air suspension can be controlled manually by the driver using a switch on the center console to select the required height change. The system will temporarily inhibit height adjustments when the vehicle is subject to cornering, heavy acceleration or heavy braking. The inhibit function prevents unsettling of the vehicle by reducing the effective spring rates. Height changes are also restricted for safety reasons, when a door is opened and the vehicle is stationary for example. Control Module The air suspension system fitted to Range Rover is controlled by the air suspension control module which is located adjacent to the passenger compartment fusebox, behind the instrument panel. The control module is housed in a plastic bracket attached to the 'A' pillar. The control module monitors the height of each corner of the vehicle via four height sensors, which are mounted in-board of each road wheel. The control module also performs an 'on-board diagnostic' function to perform 'health checks' on the system. If faults are detected, codes are stored in the control module and can be retrieved using T4. Tolerance Control Bands The air suspension control module has two ride height tolerance control bands: Tolerance Band Settings: Normal tolerance Tight tolerance. The tolerance bands are as follows: Normal ± 10 mm Tight ± 3 mm. The tight tolerance band is only used if set by T4 for diagnostics or when the vehicle has been stationary for more than 5 minutes. The control module considers the vehicle to be at target height if the current height is within the appropriate tolerance band. Height adjustments are not made until the vehicle height falls outside of the tolerance band for a pre-determined time. The time period is different depending on if the vehicle is moving or stationary. Technical Training (G538469) 19

21 2006MY Range Rover (LM) Lesson 1 General Information Geometry Changes The suspension geometry changes when moving from off-road to access heights. Refer to the following table for data: Geometry Changed Front Rear Toe change Camber change 30 mins 90 mins 10 mins 90 mins 20 (G538469) Technical Training

22 Lesson 2 Component Description Objectives On completing this lesson, you will be able to: List all of the major system components. Explain at a high level each major component function. Technical Training (G538472) 21

23 Range Rover (LP) Lesson 2 Component Description RANGE ROVER (LP) 22 (G538471) Technical Training

24 Lesson 2 Component Description Range Rover (LP) Components Review Component Location Technical Training (G538471) 23

25 Range Rover (LP) Lesson 2 Component Description Component Location Component Location - Legend Item Component Location Comments 1. ECU Below LHF seat Delay relay in the same vicinity 2. Compressor Engine bay LHS Located with valve block and has serviceable filters 3. Drier Next to air cleaner Replace if water in system 4. Solenoids Engine bay LHS Seven solenoids in total 5. Reservoir RHS of chassis Drain plug fitted to one end 6. Height sensor Front axle Potentiometer type unit 7. Height sensor Rear axle Potentiometer type unit 8. Air spring Front axle Separate to damper unit 9. Air spring Rear axle Separate to damper unit 10. Fuse box Engine bay RHS Stores system relay and fuses 11. Switch panel Air suspension control switches on Indicator warning lamp fascia panel location 24 (G538471) Technical Training

26 Lesson 2 Component Description Range Rover (LP) Front and Rear Suspension Front and Rear Suspension Assembles Technical Training (G538471) 25

27 Range Rover (LP) Lesson 2 Component Description EAS ECU Air Supply Compressor Air Suspension ECU The EAS ECU is located below the left hand seat. The ECU maintains the requested vehicle ride height by adjusting the volume of air in each air spring. Connection of the ECU to the harness is via a 35 way connector. To ensure safe operation the ECU has extensive on-board diagnostic and safety features. The ECU is not a serviceable item and will require replacement in the event of a failure. Air Supply Air supply is delivered by the compressor to raise the vehicle. The air compressor is located under the bonnet and mounted on the left hand inner wing area. A thermal switch is incorporated into the motor which permanently cuts out the compressor operation at temperatures >120 C. Below the 120 C threshold, the thermal switch monitors the compressor temperature and operates the compressor within the set parameters. To protect the compressor from dirt ingress an inlet filter is fitted to the compressor head intake port. On the outlet port a second filter is provided which acts as a silencer. The compressor filters requires changing at specific times during its service life. Filter Service The filters for the compressor require changing at specific times during its service life. Filter Change Requirements Distance Comments 24,000 39,000 30,000 Miles Kilometers Miles (USA) 26 (G538471) Technical Training

28 Lesson 2 Component Description Range Rover (LP) Drier Assembly Valve Block Assembly The air drier unit is connected into the air line between the compressor and reservoir and is mounted on the engine air cleaner housing. Drier Unit Air flow to and from the air springs is controlled via seven solenoid operated valves (five visible and two situated underneath). The solenoids are used for the following: The drier removes moisture from the pressurized air entering the air system. It is important that all exhausted air is expelled through the drier unit in the opposite direction, i.e. to atmosphere. The air drier unit is not a serviceable item. It is designed to last the life of the vehicle. The drier is regenerative, the dry exhausted air expels the moisture from the drier unit back in to the atmosphere. CAUTION: If the air drier unit is removed from the vehicle the ports must be plugged to prevent moisture or dirt ingress. If any water is found within the system then the drier must be replaced. Valve Block The role of the valve block is to control the direction of air flow. One for each air spring (x4) Inlet valve (x1) Exhaust valve (x1) Outlet valve (x1) In response to signals from the ECU, the valves allow high pressure air to flow in or out of the air springs according to the need to increase or decrease pressure. A diaphragm valve (Fig 'A' in the diagram) is operated by the outlet valve. Mounted on the valve block is a pressure switch which senses air pressure and signals the ECU to operate the compressor when required. The solenoid operated diaphragm valve ensures that all exhausted air passes through the air drier assembly. The compressor will operate when the pressure falls between: 7.2 and 8.0 bar (104 and 116 psi) It will cut-out at a rising pressure of between: 9.5 and 10.5 bar (138 and 152 psi) It is mounted next to the compressor in the left hand side of the engine bay. Technical Training (G538471) 27

29 Range Rover (LP) Lesson 2 Component Description Valve Block Components Complete the schematic above from the instructors presentation slide The valve block contains the following serviceable components: Solenoids 1 to 6 ('A' not serviceable) Drive pack assembly Pressure switch 'Green' The purpose of the Drive Pack is control of the solenoid valves through drive signals controlled by the ECU. The solenoid marked 'A' can be identified by its blue fly lead. Reservoir Location of the reservoir is on the right hand side of the chassis. 28 (G538471) Technical Training

30 Lesson 2 Component Description Range Rover (LP) Reservoir Capacity of the reservoir is 10 liters. The reservoir stores compressed air between set parameters and has one connection that serves as both the air in and air out. On the opposite end to the air supply connection is a drain plug. The drain plug has a service schedule requirement of being removed and checking for moisture content. Service Schedules 24,000 miles (39,000 km) (30,000 miles NAS) Pressure gauge adaptor LRT can be fitted in to the drain port for the checking of system pressures. Technical Training (G538471) 29

31 Range Rover (LP) Lesson 2 Component Description Height Sensors Front and Rear Height Sensors Four potentiometer type height sensors provide vehicle height information to the air suspension ECU. The sensors are mounted on the chassis and activated by links to the front radius arms and rear trailing links. Sensors are color coded to aid fitment to the correct side of the vehicle. Height sensors when replaced with service replacement units come complete with the actuating arm and drop link. Earlier sensors originally had fly leads attached, the later service units do not have a fly lead. When fitting the later style height sensors without a fly lead for a sensor that previously used a fly lead a fitting kit, consisting of a mounting plate and an electrical connector is used. Height sensors require replacement in the event of a failure and the vehicle re-calibrated to the air suspension ECU using the T4 diagnostic equipment. T4 diagnostic equipment converts the analogue feedback voltage into a digital value using an A/D convertor. The reason for the calibration process is to compensate for manufacturing variations as sensors do not all produce the same output. The generated value is then used by the T4 diagnostic equipment in the form of a count method to calibrate the air suspension ECU. Each sensor has a five volts supply from the air suspension ECU and a ground return path. A feedback voltage corresponding to vehicle height is then fed back to the air suspension ECU. 30 (G538471) Technical Training

32 Lesson 2 Component Description Range Rover (LP) In general terms the height sensor feedback voltage will increase as the vehicle rises. The rear of the vehicle will rise first, followed by the front thus avoiding any headlamp dazzle. If the vehicle is parked on uneven ground or with a wheel or wheels on the kerb, the system will lower the vehicle to the lowest spring height. Air Springs Air Springs Spring Construction The front and rear air springs are of similar construction but not interchangeable. Air spring diaphragms are not repairable and must be replaced as a complete unit if a failure occurs. Collet type connectors are used to connect the air spring port to the air harness. Air Harness Repair A repair tool is available to repair damaged or leaking air pipes. Replacement air pipe kit is available with connectors. Service Kit - RQM feet (3 meters) 4 connectors Technical Training (G538471) 31

33 Range Rover (LP) Lesson 2 Component Description Separate connectors are available using part number: STC The service tool number is: LRT To aid air leak detection use GOTEC LDS (Part No: STC 1090), this is the only recommended method for testing for air leaks. The use of a pencil sharpener is also recommended to chamfer pipe before fitting joint or collet connector. Relays and Fuses Fusebox The spray contains corrosion inhibitors and will not damage paint work, metals or plastics. WARNING: Do not use a water based liquid as this can get into the air system and contaminate the solenoid valves causing problems later in service life. The damaged section can be cut-out and replaced with a connector repair joint or the collet connector can be replaced as a service kit, consisting of an 'O' ring and collet. When cutting the air harness pipe: use service tool LRT ensures a clean square cut. NOTE: Two repairs/cuts is the maximum engineering recommendation when repairing a connector. RHS Engine Bay Fusebox The air suspension relays and fuses are located in the RHS engine bay fusebox. Engine Bay Fusebox Relay or Fuse Relay 20 Rating Comments Compressor and valve block supply Fuse 1 Fuse 17 Fuse 24 Fuse 29 Fuse 35 Fuse amp 10 amp 5 amp 10 amp 10 amp 40 amp Supply to instrument cluster (next to BCU) Stop lamp switch supply (inhibits height changes) Ignition supply (Speed signal from BCU and ABS ECU) EAS delay timer unit Height change switch and warning lamps Compressor and valve block supply NOTES: 32 (G538471) Technical Training

34 Lesson 2 Component Description Range Rover (LM) RANGE ROVER (LM) Technical Training (G538471) 33

35 Range Rover (LM) Lesson 2 Component Description Components Review Component Location NOTES: 34 (G538471) Technical Training

36 Lesson 2 Component Description Range Rover (LM) Component Location Component Location - Legend Item Component Location Comment 1. RHF height sensor Front subframe to lower control arm Different units for Xenon headlamps 2. RHF air spring Between subframe and lower control Rotary coupling with peg arm locator 3. Switch pack assembly Center console Separate switch for access mode located in driver's door panel 4. Reservoir and valve block RH sill area Valve block available separately 5. RHR damper Between body and lower control arm Bilstein units 6. RHR air spring Between subframe and lower control 'D' shaped retaining clip arm 7. Cross link valve Rear wheel arch area Not driver controlled 8. Pressure relief valve Spare wheel compartment Internal pressure relief valve was 13.7 bar, the external relief valve is Compressor Spare wheel compartment Sealed unit 10. LHR air spring Between subframe and lower control 'D' shaped retaining clip arm 11. LHR damper Between body and lower control arm Bilstein units 12. LHR height sensor Between subframe and lower control Check VIN for type of arm sensor fitted 13. RHR height sensor Between subframe and lower control Different sensor for Xenon arm headlamps 14. ECU LH end of fascia 15. LHF air spring Between subframe and lower control Rotary coupling with a peg arm for locating 16. LHF height sensor Between subframe and lower control Check VIN for type of arm sensor fitted Technical Training (G538471) 35

37 Range Rover (LM) Lesson 2 Component Description Item Component Location Comment 17. Cross link valve Between subframe and lower control Not driver controlled arm Front Suspension Assembly Front Suspension 36 (G538471) Technical Training

38 Lesson 2 Component Description Range Rover (LM) Front Suspension Item Description RHF strut assembly RH tie rod Subframe body mounts Front cross link valves (if fitted) Anti-roll bar LHF strut assembly LH tie rod LHF hub assembly LH lower arm LH anti-roll bar link LHF height sensor Front subframe RHF height sensor (partially hidden from view) RH lower arm RH anti-roll bar link RHF hub assembly Technical Training (G538471) 37

39 Range Rover (LM) Lesson 2 Component Description Rear Suspension Assembly Rear Suspension 38 (G538471) Technical Training

40 Lesson 2 Component Description Range Rover (LM) Rear Suspension Item Description Subframe mounts RHR air spring RH lower wishbone Anti-roll bar LHR air spring LH lower wishbone Rear cross link valve RHR hub assembly RH damper RH upper wishbone LH damper Compressor assembly LHR hub assembly LH toe control arm LH upper wishbone LHR height sensor Rear subframe RHR height sensor RH toe control arm Technical Training (G538471) 39

41 Range Rover (LM) Lesson 2 Component Description Cross Link Valves Cross Link Valve Cross Link Valve - Legend Item Description Electrical connector RH air spring supply and return RH air spring supply and return from valve block Cross link valve body LH air spring supply and return LH spring supply and return from valve block Cross Link Valve Location The front cross link valve is located at the rear of the RHF wheel arch, behind the wheel arch liner (where fitted). The rear valve is located towards the top of the RHR wheel arch and is also situated behind the wheel arch liner. 40 (G538471) Technical Training

42 Lesson 2 Component Description Range Rover (LM) NOTE: On later vehicles, the front cross-link valve was deleted and a modified air harness and air suspension ECU was also installed. The deletion of the cross-link valve affects the following vehicles: VIN to , VIN and and from VIN onwards. Attachment of the valves to the vehicle body is by three rubber mounted fixings to isolate solenoid valve operation. Cross Link Valve Operation The cross link valves comprise of a single large solenoid valve with connections to the LH and RH air springs and also connections for each air spring from the reservoir mounted valve block. Each solenoid operated valve is controlled by the air suspension ECU. When the solenoid valve is energized the cross link valve connects the two air springs together, thus allowing air to flow between them if required. This feature provides additional suspension articulation which improves the off-road capabilities of the vehicle and an improvement in low speed ride comfort. The air suspension ECU senses the vehicle is off-road by comparing rapid changes in signals from the ride height sensors. Cross link valve operation is fully automatic, and requires no driver intervention at any time. The cross link valves only operate in off-road mode and operation is governed by the off-road mode speed threshold. Height sensor inputs to the air suspension ECU are used in the decision as to when the cross link valves operate. With the driver's height control switch in off-road mode position, the system enters a stand by condition until the ECU decides to operate the valves via height sensor information. Service Requirements When removing a cross link valve 'DO NOT' depressurize the air suspension system before raising the vehicle. In the event of having to remove a 'Voss' connector from any air suspension component, the connector must be left attached to the air pipe being removed. Removing the Voss connector from the air pipe could cause the connector to scratch the pipe and increase the likelihood of air leaks. Technical Training (G538471) 41

43 Range Rover (LM) Lesson 2 Component Description Compressor Assembly Air Supply Compressor Compressor Assembly - Legend Item Description Electric motor Compressor Compressor temperature sensor 42 (G538471) Technical Training

44 Lesson 2 Component Description Range Rover (LM) Item Description Electrical and air supply connector High pressure exhaust valve Rubber mountings (x3) Exhaust hose Exhaust pilot valve Air Supply Unit Location The air supply unit is located in a sealed housing mounted in the spare wheel compartment. Four bolts secure the air supply unit to the vehicle by threaded inserts in the wheel compartment floorpan. System Connection The assembly is connected to the system through a single air supply pipe with wiring harness and multi-plug. The earlier air pipe connection was superseded by the introduction of a revised pressure relief valve on later vehicles. Pipe protection as it passes through the wheel well floorpan is through the use of a rubber grommet. It is important to ensure that this grommet is not disturbed during any service work and that it is correctly installed. Incorrect installation will allow water to enter the wheel well area leading to possible damage and failure of the air supply unit. Service Requirements Removal of the air supply unit does not require the system to be depressurized. The corner and reservoir valves close-off, thus retaining the air within the air suspension system. Compressor The unit comprises of a single piston compressor, a 12v electric motor, a solenoid operated pilot valve, a pressure relief valve and an air drier unit. The electric motor, compressor, air drier and pressure limiting and exhaust valve are mounted on a frame which in turn is mounted on flexible rubber mountings to reduce operating noise. Air Supply Operation The electric motor drives a crank with an eccentric pin to which the connecting rod is attached. The connecting rod has a piston which fits in the bore of the compressor. Operation of the motor rotates the crank, moving the piston in the bore of the compressor. The compressor is attached with special bolts to the motor housing and sealed with an 'O' ring. A temperature sensor is located on the compressor housing. The sensor measures the compressor temperature which is then used by the air suspension ECU (this is discussed further in system inhibits). Technical Training (G538471) 43

45 Range Rover (LM) Lesson 2 Component Description Air Drier Attached to the compressor is an air drier unit which contains a silicate box for removing moisture from the compressed air. All air that is supplied to inflate the air springs passes through the air drier unit. When the air springs are deflated, the exhausted air also passes back through the air drier assembly, thus removing the moisture from the drier unit and regenerating the silicate material. The pressure limiting valve also operates when the exhaust pilot valve is opened, thus allowing air returning from the air springs to be exhausted. System Pressure The compressor is used to supply air pressure to the air suspension reservoir. The ECU monitors the pressure within the reservoir to maintain a pressure of 12.3 bar (178 psi) when the engine is running. Exhaust Valve Attached to the air drier unit is a solenoid operated exhaust pilot valve which is opened when the air springs are to be deflated. Located in the same housing as the exhaust pilot valve is a pressure limiting valve which protects the air springs from over inflation. The valve is pneumatically operated, responding to air pressure applied to it in order to overcome the pressure of the spring located behind the valve. System Inhibits There are a number of conditions that will inhibit operation of the air suspension compressor. It is vitally important that these inhibits are not confused with a system malfunction. A full list of compressor inhibits is contained in the air suspension control section. A temperature sensor is located within the compressor and should the compressor temperature rise above set limits, the ECU will inhibit compressor operation. 44 (G538471) Technical Training

46 Lesson 2 Component Description Range Rover (LM) Reservoir Assembly Reservoir Assembly Item Description Reservoir front fixing Reservoir rear fixing Air pressure sensor Reservoir Air harness connector Reservoir to valve block air supply pipe Valve block The air suspension reservoir is located under the RH sill of the vehicle. On vehicles up to VIN the reservoir is fabricated from aluminum. On vehicles from VIN the reservoir is fabricated from steel. The reservoir is secured with four bolts to the underside of the vehicle. Technical Training (G538471) 45

47 Range Rover (LM) Lesson 2 Component Description The reservoir has an additional bracket on the forward facing end which provides the mounting for the valve block. The purpose of the reservoir is to supply pressurized air to the four corner air spring assemblies through the valve blocks, to enable the air suspension system to carry out ride height changes. A pressure sensor is screwed into the rear face of the reservoir. The sensor is connected to the air suspension ECU and monitors the pressure within the reservoir. Bulletin LM states replacement of the pressure sensor is achieved by renewing the sensor as a separate item and does not require the changing the air supply reservoir assembly as a complete component. Height Control The ECU controls the operation of the air suspension compressor to maintain a pressure of 12.3 bar (178 psi) only whilst the engine is running. If an upward height change request is made when the engine is not running, air pressure within the reservoir is used to lift the vehicle. NOTE: Earlier vehicles had a pressure limit of 13.7 bar (199 psi). However, the system pressure was been reduced to 12.3 bar (178 psi) with the introduction of a separate pressure relief valve, refer to Bulletin A/B/D 293 issued When the engine is started, the ECU runs the compressor to increase reservoir pressure to 12.3 bar (178 psi). Location of the valve block is mounted forward of the air supply reservoir under the RHS sill area of the vehicle. The reservoir supplies pressurized air to the four corner air spring assemblies via the valve block, to enable the air suspension system to carry out ride height changes. Three nut and stud fixings secure the valve block to the reservoir bracket. The studs are bonded into rubber mounts which isolates solenoid operation from the vehicle. Each valve block contains five solenoid operated valves which are controlled by the air suspension ECU. Four of the valves, known as corner valves, control the air flow to and from the air springs via the cross link valves. Should the reservoir pressure drop below 9 bar (130 psi) and an upward height change request is made, the lift procedure is performed by the compressor. 46 (G538471) Technical Training

48 Lesson 2 Component Description Range Rover (LM) Height Sensors to VIN Height Sensor Assemblies Item Description Front height sensor bracket Sensor fixing Suspension link securing nut Suspension connecting link Link arm retaining nut Height sensor electrical connection Height sensor Link arm securing bolt Suspension link securing nut Height sensor lever Rear height sensor bracket Technical Training (G538471) 47

49 Range Rover (LM) Lesson 2 Component Description Height sensors are located at each corner of the vehicle to monitor the vehicle ride height changes. The sensors are mounted on the front and rear subframe, with a mechanical link to the suspension lower arms. There are six different types of sensors fitted to the Range Rover (LM). These are as follows: Sensor Variants LHF height sensor RHF height sensor RHF height sensor LHR height sensor RHR height sensor RHR height sensor All vehicles Halogen headlamps fitted Xenon headlamps fitted (White stripes for identification) All vehicles Halogen headlamps fitted Xenon headlamps fitted (White stripes for identification) Height Sensor Attachment The height sensors are attached to brackets located on the subframe and are connected via links to the lower control arms. The links enable articulation of the lower control arm to allow for suspension travel. Connector Configuration Each sensor is connected by a six pin multi-plug. Standard height sensors use three of the six available pins. However height sensors for vehicles fitted with Xenon headlamps utilize all six. Sensor Differences The height sensors contain a circuit board with a Hall effect sensor. The sensor is supplied with a reference voltage from the air suspension ECU which in-turn measures the returning voltage (feedback) to determine the sensor arm position. Height sensors used on vehicles fitted with Xenon headlamps use a sensor with a second circuit board. This second circuit board feedback information is used by the Xenon headlamp leveling ECU. Service Points The front height sensor ball jointed linkage is a serviceable item. However, the rear height sensor linkage cannot be serviced and must be changed as a complete height sensor assembly. NOTE: From 26th May 2004 the height sensors changed on the track from hall effect type to contact type. The new sensors are fitted to vehicles from VIN The impact on service means that there are four new sensor part numbers. Sensors are handed left to right and identified by white levers for the left hand sensors (same as Discovery 3 / LR3). 48 (G538471) Technical Training

50 Lesson 2 Component Description Range Rover (LM) Each sensor comprises a sensor body which contains a single track rotary potentiometer, a lever arm and a drop link. The sensor is supplied with a reference voltage from the air suspension ECU which measures the returned voltage to determine the sensor arm position. Fixings have also changed (same as Discovery 3 / LR3), i.e. self tap. Height Sensors from VIN Parts are interchangeable on vehicles before VIN and therefore a vehicle can have a mixture of old and new type sensors. This is only applicable to sensors on vehicles without xenon headlamps. The new sensors cannot be replaced for the old type sensors with a white identification stripe. Item Description Front height sensor bracket Height sensor securing fixings Rear height sensor bracket Height sensor electrical connection Height sensors Height sensor operating link arms Link securing fixing Ensure the front height sensor linkage is fitted correctly. It is possible to locate the arm 180 degrees out of correct alignment. Technical Training (G538471) 49

51 Range Rover (LM) Lesson 2 Component Description Air Springs Each air spring comprises of a top plate assembly, an air bag and a base piston. Air Spring Components Air Springs Attachment of air bag assembly to the top plate and the piston is by a crimped ring. The air bag is made from a flexible rubber material which allows the bag to expand with air pressure and deform under load. Air Spring Assembly The front air spring top plate assembly comprises the plastic top plate with a spigot which protrudes through a hole in the subframe. On the side of the top cap is an Voss air connector which allows for the attachment of the air supply pipe from the cross link valve. The piston is manufactured in plastic and shaped to allow the air bag to roll over its outer diameter. The base of the rear piston has a splined stud in the center and an offset timing peg for correct orientation of the air spring into the lower wishbone. Item Description Air Spring Fitment The rear air springs are located rearward of the dampers and are retained between the subframe and the lower wishbone. Attachment of the rear air spring to the lower wishbone with a screw fixing which is fitted from the underside of the wishbone into the splined stud on the base of the piston. The top plate for the rear air spring is attached to the subframe via an integral 'D' shaped spigot which is secured with a retaining clip. 1. Aperture cover 2. Sealing plate 3. Securing nut 4. Front air spring 5. Air pipe Voss connector 6. Rear air spring Construction The air springs on the front and rear suspension are similar in construction. Both air springs are manufactured from flexible rubber. 50 (G538471) Technical Training

52 Lesson 2 Component Description Range Rover (LM) Each air spring forms an air tight cavity which provides the required spring rate for each corner of the vehicle. As the air spring is compressed, the rubber material compresses and rolls down the side of the vertical housing below the spring. Air Supply Connection An air connection port is located on the top of each spring and allows air to be added or removed from each air spring as required by the air suspension ECU. The air connection port is connected using a Voss connector and nylon pipe to the valve block on the reservoir. When removing the Voss connector from any air suspension component, the connector must be left attached to the air pipe. Removing the connector from the air pipe could cause the connector to scratch the pipe and increase the likelihood of air leaks. Service Care Points When servicing an air spring or the complete air suspension system, depressurization is required. Replacement of an individual air spring does not require full air suspension system depressurization. Only the corner concerned need be depressurized. Before carrying out depressurization of the air suspension system, the vehicle weight must be supported. Prior to removing the vehicle support, each air spring must be fully pressurized before the weight of the vehicle is re-applied to it. Air Harness Identification The air harness system is interconnected via yellow and black nylon pipes. Yellow = RHS Black = LHS The pipes are attached to the subframe and vehicle body with clips. This is to ensure that the correct routing is maintained. The pipes have timing marks which align with the various clip positions. The timing marks exist in the form of a white band around the pipe thus indicating the clip position. If the correct routing is not observed, un-necessary tension at the pipe joints will occur, resulting in possible early failure. Technical Training (G538471) 51

53 Range Rover (LM) Lesson 2 Component Description Pressure Control Pressure Relief Valve A pressure relief valve is connected to the air pipe between the compressor and the reservoir. The pressure relief valve is installed in the RHF corner of the spare wheel well and provides a safety back-up for the ECU pressure control function, to limit system pressure. NOTE: Bulletin A/B/D issue date states earlier vehicles had a pressure relief limit of 13.7 bar (199 psi). The pressure relief was reduced with the introduction of an external pressure relief valve and an ECU software upgrade. If the pressure of the air from the compressor increases above 12.3 bar (178 psi), the pressure relief valve opens and releases the excess pressure to atmosphere. Leak Detection Air leak detection can be carried out using a Land Rover approved non water based leak detection spray. If the vehicle appears to be leaking, perform a leak check on all aspects of the system, i.e. air spring pipe fittings and associated connections on the valve block, cross link valves, air spring and reservoir. Failure to correctly diagnose leakage will result in un-necessary exchange of serviceable components and re-occurrence of the original problem. 52 (G538471) Technical Training

54 Lesson 2 Component Description Discovery II DISCOVERY II Technical Training (G538471) 53

55 Discovery II Lesson 2 Component Description Component Review Component Location 54 (G538471) Technical Training

56 Lesson 2 Component Description Discovery II Component Location Item Description Item Description 1. Off-Road mode switch 7. Air intake filter 2. SLS warning lamp 8. LHR air spring 3. Instrument cluster 9. LHR height sensor 4. Off-Road warning lamp 10. Air supply unit 5. RHR height sensor 11. SLABS ECU (behind glove box) 6. RHR air spring Self Leveling Rear Suspension Rear Suspension Components Item Description Item Description 1. Air pressure pipe connection (x2) 2. Air Spring (x2) Technical Training (G538471) 55

57 Discovery II Lesson 2 Component Description Self Leveling Components Air distribution unit. Silencer. Two height sensors. Two air springs. Air intake filter. Air suspension height switch. Air suspension warning lamp. Off-road mode warning lamp. Self Leveling / Anti Lock Brakes (SLABS) ECU. Air Distribution Unit The air distribution unit is located on the LH chassis rail, beneath the floor panel. No routine maintenance is required for the assembly. The housing contains the following components. Air Distribution Unit: Compressor Air drier assembly Air valve Pressure limiting valve Electric motor Air Distribution Assembly 56 (G538471) Technical Training

58 Lesson 2 Component Description Discovery II Air Distribution Item Description Item Description 1. Compressor electrical connector 10. LH air valve electrical connector (blue harness connector) 2. Electric motor 11. LH air valve 3. Air intake hose 12. LH air spring supply pipe 4. Compressor 13. Air supply /Exhaust pipe 5. Air drier unit 14. RH air spring supply pipe 6. Pressure limiting valve 15. RH air valve 7. Exhaust hose 16. RH air valve electrical connector (natural harness connector) 8. Exhaust valve electrical connector (black 17. Air distribution housing harness connector) 9. Exhaust valve Compressor The role of the compressor is to supply compressed air to the rear air springs. Compressor Unit The relay is controlled by the Self Leveling Anti- lock Brake System (SLABS) ECU (the SLABS ECU is located behind the passenger side glove box). Compressor Operation The air supply unit consists of a 12v electric motor, a compressor with a drier element, a pressure limiting valve and two air supply control valves. Exhaust and the air supply control valves are solenoid operated responding to signals from the SLABS ECU. The electric motor drives a crank with an eccentric pin to which a connecting rod is attached. A piston connects to the connecting rod and fits into the bore of the compressor. Power Supply When the motor is operated it rotates the crank, moving the piston in the bore of the compressor. A relay located in the engine bay fuse box supplies the compressor with its 12v power requirements. Technical Training (G538471) 57

59 Discovery II Lesson 2 Component Description Air Pressure Limiting Valve The air pressure limiting valve is attached to the end of the air drier unit. The limiting valve protects the air springs from over inflation. Pressure Limiting Valve All air exhausted from the system passes through the drier unit in the opposite direction. The air drier is regenerative in that exhaust air absorbs the moisture in the drier element and expels it into the atmosphere. The air drier element is designed to last the life of the vehicle and in non-serviceable. Air Intake Filter The air intake and filter for the compressor is located behind the LHR light cluster in the 'E' post. Air Intake Location When the exhaust valve is opened, the pressure limiting valve also opens. The valve is pneumatically operated, responding to air pressure applied to it. Air Drier Unit The air drier unit is built into the compressor assembly. The air drier unit contains a silicate box which removes moisture from the compressed air entering the system. Air Drier Assembly 1. Air intake filter Air Intake System 2. Quick release connector 58 (G538471) Technical Training

60 Lesson 2 Component Description Discovery II The plastic molded housing contains a felt and foam air filter and is replaceable (refer to repair procedure in the workshop manual). Operating Valves The filter removes particulate matter from the air drawn in by the compressor. For correct service intervals refer to the service maintenance check sheet. It is recommended that vehicles used extensively in arduous / off-road conditions will require the air intake filter to be replaced at more regular intervals. Air Valves The self leveling suspension system air control valves control the operation of the air springs located at the rear of the vehicle. There are three solenoid actuated valves incorporated within the air distribution unit. Right spring valve Left spring valve Exhaust valve 1. Right air spring valve Operating Valves 2. Left air spring valve 3. Exhaust valve Vehicle Lifting For the LHS of the vehicle to rise, the left spring valve is opened and the compressor run. The same operation with the right spring valve, raises the RHS of the vehicle. Vehicle Lowering To lower the LHS of the vehicle, the left hand valve is opened along with the exhaust valve. Technical Training (G538471) 59

61 Discovery II Lesson 2 Component Description Likewise, the same operation is completed for the right hand valve and exhaust valve to lower the RHS of the vehicle. Height Sensors Height Sensor Valve Location The LH and RH spring valves are located at the forward end of the air distribution housing. Valve Control Each control valve can be individually operated by the SLABS ECU. The exhaust valve is located with the pressure limiting valve and is solenoid operated by the SLABS ECU. The exhaust valve directs air from the air spring(s) and control valve(s) to atmosphere when required. All expelled air passes through the drier element to regenerate the silica material. Silencer The silencer is connected into the air lines behind the air distribution unit. It has two chambers, one to reduce compressor pulsing noises at the air intake filter, the other to minimize Item Spacer Link end Description exhaust noise. 3. Link rod 4. Link end 5. Sensor arm 6. Sensor body Sensor Location The height sensors are located on the chassis, with the sensor arms, a link rod and two link ends attached to the radius arms. 60 (G538471) Technical Training

62 Lesson 2 Component Description Discovery II The link ends permits articulation of the arm to allow for suspension travel. The lower link arm is attached to a lug on top of the radius arm. Sensor Connector Each sensor is connected to the main chassis harness by a multiplug. The three pin multiplug provides the following electrical connections: Ground 5v supply Feedback signal Sensor Operation Each sensor operates on the Hall effect principle. A magnet is attached to the shaft and rotates with the movement of the arm. The magnetic flux generated acts on a Hall effect sensor and depending on its position, varies the current across the sensor. If, for any reason, the sensors are replaced, or removed and refitted, a calibration process must be completed. This is to ensure that the SLABS ECU can determine the correct height value of the vehicle from the height sensor voltage signal. The calibration procedure involves using T4 diagnostic equipment and a set of special calibration setting blocks (LRT ). Ride Characteristics Using air springs provides the vehicle with an improved secondary ride. Secondary ride is the term used to describe vibrations / oscillations caused by the vehicle reacting to minor road imperfections. Air Spring Construction The rear air springs are manufactured using a light, but, reinforced material for strength and durability. The current generated is measured, amplified and passed to the SLABS ECU as a linear output feedback voltage signal. The voltage signal varies according to the angular position of the sensor arm. The signal is processed by the SLABS ECU and from this the ECU can determine the height of the vehicle. Service Points Height sensor voltage outputs vary from sensor to sensor. This is a manufacturing variability which has to be compensated for when the sensor is fitted to the vehicle. Technical Training (G538471) 61

63 Discovery II Lesson 2 Component Description Air Springs Rear Air Spring Spring Location Each air spring is located at its base by a fabricated platform on the rear axle. The top of the spring locates in a fabricated bracket attached to the outside of each chassis. The plastic base piston is recessed and has a boss with two lugs molded in the center for attachment to the axle. The piston is secured by locating lugs in a slotted hole in the axle platform and rotating the spring through 90 degrees locates the lugs in the slot. The plastic top plate has grooved pins which locate through holes in the chassis bracket. Two spring clips locate on the grooved pins and retain the top of the spring in position. Spring Assembly Each air spring comprises a top plate, an air bag and base piston. Rear Air Spring 1. Top plate 2. Voss connector 3. Air bag 4. Piston The air bag is attached to the top plate and the piston with crimped rings. The air bag is made from a fibre reinforced flexible rubber material which allows the spring to expand with air pressure and deform under load. The top plate comprises the two bonded grooved pins and a female Voss connector in the center. The Voss connector allows for the attachment of the air supply pipe from the air supply unit. The piston is also plastic and is shaped to optimize the springs characteristics. 62 (G538471) Technical Training

64 Lesson 2 Component Description Discovery II SLABS ECU ECU Item Description Item Description 1. SLABS ECU 3. BCU (ref only) 2. Bracket 4. ACE ECU (ref only) SLABS ECU Location The SLABS ECU is mounted on a bracket behind the passenger glove box and can be identified from other ECU's by its five connectors. The five electrical connectors are located on the lower face of the ECU. The twelve, six and eighteen pin connectors are used to supply inputs and outputs to and from the ECU whilst the remaining two connectors are used for ABS operation. Battery Power Supply The SLABS ECU receives a continuous battery supply from 'Fuse 11' in the engine compartment fusebox. Ignition Power Supply An ignition 'ON' signal is supplied from the ignition switch via 'Fuse 28' in the passenger compartment fusebox. Technical Training (G538471) 63

65 Discovery II Lesson 2 Component Description The ECU has the ability to control when it requires power and is not reliant on the ignition signal to power up the ECU. Event Timers Incorporated into the ECU is a counter which times the operation of the SLS system and prevents the compressor exceeding its duty cycle. The ECU can remain powered for up to 1.5 hours after ignition off is sensed which allows the counter to continue running to avoid an ignition cycle resetting the event counter. Door Input If any of the doors are opened, this will power up the ECU irrespective of the ignition switch position. The door open signal is sensed by the door switch completing an earth path which is sensed by the ECU. The door open signal powers the ECU for up to 30 minutes. This allows the vehicle to re-level when a load is removed or passengers leave the vehicle. 64 (G538471) Technical Training

66 Lesson 2 Component Description Discovery II System Components System Components Schematic Technical Training (G538471) 65

67 Discovery II Lesson 2 Component Description System Operation Item Description Item Description 1. Battery supply (via SLABS relay) 12. RH air valve 2. Ignition supply 13. LH air valve 3. RH height sensor 14. Exhaust valve 4. LH height sensor 15. Diagnostic socket 5. Off-Road mode warning lamp 16. Off-Road mode switch 6. Audible warning speaker 17. SLS remote handset 7. Instrument cluster 18. Body Control Unit (BCU) 8. SLS warning lamp 19. Door switches 9. Fusible link SLABS ECU 10. SLS relay 21. Engine Control Module (ECU) 11. Air supply unit System Operation Self leveling is accomplished automatically when the engine is running (the engine ECU sends an engine speed signal to the SLABS ECU to indicate when the engine is running). If the air suspension is too high, the LH and RH spring valves will open, along with the exhaust valve, purging air until the height sensors inform the ECU that the target height has been reached. The height sensors inform the SLABS ECU at what the height the vehicle is currently set. If the rear suspension is too low, the SLABS ECU switches on the compressor by actuating the compressor relay. The LH and RH spring valves will open simultaneously (providing the vehicle is on flat ground), allowing compressed air to the air springs. The exhaust valve will remain closed. The height sensors then inform the ECU that the target height has been reached, the compressor stops and the valves are closed. 66 (G538471) Technical Training

68 Lesson 2 Component Description Discovery 3 / LR3 DISCOVERY 3 / LR3 Technical Training (G538471) 67

69 Discovery 3 / LR3 Lesson 2 Component Description Component Review System Components 68 (G538471) Technical Training

70 Lesson 2 Component Description Discovery 3 / LR3 Component Location Item Description Item Description 1. Front RH air spring damper module 11. Rear LH height sensor 2. Front RH height sensor 12. Upper acoustic cover 3. Air suspension control module 13. Lower acoustic cover 4. Air suspension control switch 14. Air supply unit 5. Rear RH height sensor 15. Reservoir valve block 6. Rear RH air spring damper module 16. Air reservoir 7. Air supply unit silencer 17. Front LH height sensor 8. Rear LH air spring damper module 18. Front LH air spring damper module 9. Air intake filter 19. Front valve block 10. Rear valve block Control Module Air Suspension Module Technical Training (G538471) 69

71 Discovery 3 / LR3 Lesson 2 Component Description Item Description Item Description 1. Air Suspension Control Module 4. Connector C Connector C Connector C Connector C2320 Control Module Location The air suspension control module is located behind the instrument panel, on the driver's side 'A' post. Attachment to the 'A' post is via a single fixing and two plastic clips. Calibration A calibration routine is performed using the T4 diagnostic equipment to access the position of each corner of the vehicle and record the settings in the ECU memory. Once set, the calibration is not required to be performed again unless: Air suspension control module is removed or replaced Height sensor is removed or replaced Suspension arm to which the sensor is connected is removed or replaced If the removed height sensor is subsequently refitted, the calibration procedure will have to be performed to ensure the integrity of the system. If the air supply unit, the reservoir, a valve block, a damper module or the air harness is removed or replaced, the system will not require recalibration. Inputs and Outputs Four harness connectors are used by the air suspension control module for all inputs and outputs. The following tables show the details of the signals or electrical supplies on each connector pin. 70 (G538471) Technical Training

72 Lesson 2 Component Description Discovery 3 / LR3 Air Suspension Control Air Suspension Control Switch Control Switch Item Description Item Description 1. Crawl mode lamp 6. Raising lamp 2. Access mode lamp 7. Off-road mode lamp 3. Lowering lamp 8. Terrain Response rotary control 4. On-road mode lamp 9. Transfer box range switch 5. Air suspension switch 10. Hill Descent Control (HDC) switch The air suspension control switch is located in the center console, behind the manual or automatic transmission selector lever. The switch is a three position, non-latching switch which allows selection of the following driver selectable modes. Selection Modes: On-road mode Access mode Crawl (locked at access) mode The air suspension switch can be moved forwards or backwards from its central position. Technical Training (G538471) 71

73 Discovery 3 / LR3 Lesson 2 Component Description The switch is non-latching and returns to the central position when released. The switch completes an earth path to the air suspension control module when operated. This earth path is completed on separate wires for the raise and lower switch positions, allowing the control module to determine which selection the driver has made. The air suspension switch has six symbols which illuminate to show the current selected height and the direction of movement. The raise and lower symbols will flash and a warning tone will be emitted from the instrument cluster sounder when a requested height change is not allowed, i.e. vehicle speed too fast. A flashing symbol indicates that the air suspension system is in a waiting state or that the system will override the driver s selection because the speed threshold is too high. The driver can also ignore the system s warnings signals and allow the height to change automatically. For example, increasing the vehicle speed to more than 25 mph (40 km/h) will cause the control module to automatically change the ride height from off-road mode to on-road mode. Valve Blocks Front and Rear Valve Blocks 72 (G538471) Technical Training

74 Lesson 2 Component Description Discovery 3 / LR3 Item Description Item Description 1. Isolation rubber mounts (x3) 8. RHF air spring, air harness connection 2. Location slots 9. Rear valve block, valves and solenoid assembly 3. Front valve block, valves and solenoid 10. RHR air spring, air harness connection assembly 4. Front bumper 11. Air inlet /outlet connection 5. Electrical connector 12. LHR air spring, air harness connection 6. LHF air spring air harness connection 13. Rear suspension turret 7. Air inlet /outlet connection The front and rear axle valve blocks are similar in their design and construction and controls air supply and distribution to the front or rear pair of air spring damper modules respectively. The difference between the two valve blocks is the connections from the valve block to the left and right hand air spring damper modules and the valve sizes. It is important that the correct valve block is fitted to the correct axle, otherwise leveling will be impaired due to the different valve sizing. Fitting valve blocks incorrectly would not actually stop the air suspension from functioning. But will result in slow raise and lower times and uneven raising and lowering between the front and rear axles. Valve Block Location The front valve block is attached to the right hand end of the front bumper. The rear valve block is located on the forward face of the left hand suspension turret. Connection Valve blocks are fitted with isolation rubber mounts to reduce possible operational noise from being transmitted. The front and rear valve blocks each have three Voss type air pipe connection fittings. One connection is an air pressure inlet / outlet from the reservoir block. The remaining two connections provide the pressure connections to the left and right air spring assemblies. Each valve block contains three solenoid operated valves: two corner valves and one cross link valve. Each solenoid valve is controlled individually by the air suspension control module. The solenoids have a resistance value of 2 20 C (68 F). Corner Valves The corner valves control the flow of air into and out of the individual air springs. When the solenoid is de-energized, the corner valves are held in a closed position by internal springs. Technical Training (G538471) 73

75 Discovery 3 / LR3 Lesson 2 Component Description When the solenoid is energized, the valve armature moves and allows air flow into or out of the air spring. Cross Link Valves The cross link valves provides a connection between the two air springs on the same axle. When de-energized, the cross link valve prevents air passing from one air spring to another. When the solenoid is energized, the valve spool moves and allows air to pass from one air spring to the other. This increases wheel articulation and improves ride comfort at low vehicle speeds. Reservoir Valve Block Reservoir Valve Block Item Description Item Description 1. Chassis mounting bracket 6. Reservoir connection 2. Location slot 7. Rear valve block connection 3. Isolation rubber mounts (3 off) 8. Front valve block connection 4. Electrical connector 9. Air supply unit connection 5. Reservoir valve block, valves and solenoid 10. Pressure sensor assembly Reservoir Valve Block The valve block also contains the air suspension system pressure sensor. The reservoir valve block controls the storage and distribution of air to and from the reservoir. 74 (G538471) Technical Training

76 Lesson 2 Component Description Discovery 3 / LR3 Valve Block Location The reservoir valve block is attached to a bracket on the outside of the left hand chassis rail. Position of the valve block is between the reservoir and the air supply unit. The valve block is located within the air supply unit acoustic box to protect it from dirt ingress and damage from stones. Valve Block Attachment The valve block has three attachment lugs which are fitted with isolation rubber mounts which locate in the chassis bracket which has three slotted holes. The isolation rubber mounts locate in the 'V' shaped slots and are pulled downwards into positive location in the slots. Connections The valve block has four air pipe connections which use 'Voss' type air fittings. The connections provide for air supply from the air supply unit, air supply to and from the reservoir and air supply to and from the front and rear valve blocks. The connections from the air supply unit and the front and rear control valves are all connected via a common gallery within the valve and therefore are all subject to the same air pressures. Operation The reservoir supply is utilized as much as possible to aid speed of response from the system. However, the system will alternate between reservoir and compressor supply as dictated by system pressures. The reservoir valve block contains a solenoid operated valve which is controlled by the air suspension control module. The solenoid valve controls the pressure supply to and from the reservoir. The solenoid has a resistance value of 2 Ohms at a temperature of 20 C (68 F). When energized, the valve spool moves allowing air to pass in or out of the reservoir. Reservoir Pressure The reservoir valve block also contains a pressure sensor which can be used to measure the system air pressure in the air springs and the reservoir. The pressure sensor is connected via a harness connector to the air suspension control module. The control module provides a 5v reference voltage to the pressure sensor and monitors the return signal voltage from the sensor. Using this sensor, the control module controls the air supply unit operation and therefore limits the nominal system operating pressure to 16.8 bar (244 lb in²). Maximum pressure is a nominal 23 bar (333 lb in²), however the reservoir is tested to a maximum of 35 bar (507 lb in²). Technical Training (G538471) 75

77 Discovery 3 / LR3 Lesson 2 Component Description Air Supply Assembly Air Supply Unit 76 (G538471) Technical Training

78 Lesson 2 Component Description Discovery 3 / LR3 Air Supply Unit - Legend Item Description Item Description 1. Mounting bracket 8. Isolation mounting rubber (2 off) 2. Air drier unit 9. Electric motor 3. Pilot exhaust valve solenoid and temperature 10. Isolation mounting rubber (1 off) sensors harness connector 4. Motor harness connector 11. Pilot air pipe 5. Intake port 12. Pressure outlet to pilot exhaust valve 6. Pilot exhaust valve 13. Compressor cylinder head temperature sensor 7. Exhaust valve 14. Compressor Acoustic Box Acoustic Covers Technical Training (G538471) 77

79 Discovery 3 / LR3 Lesson 2 Component Description Item Description Item Description 1. Upper cover 3. Air supply unit 2. Lower cover 4. Reservoir valve block Component Location The air supply unit is located on the outside of the left hand chassis rail, forward of the upper control arm. The unit is attached to the chassis rail and is protected by an acoustic box. Service Components Servicing is limited to the following components: Air drier unit Pilot exhaust pipe Rubber mounts Acoustic Box The acoustic box, which comprises of two parts; upper and lower and surrounds the air supply unit. The box is a plastic molding which is lined with an insulating foam which controls the operating noise of the air supply unit. The reservoir valve block is also located in the acoustic box. Air Supply Unit The air supply unit comprises the following major components: Piston compressor 12V electric motor Solenoid operated pilot valve Exhaust valve Air drier unit The air supply unit can be serviced in the event of component failure. Component Attachment The air supply unit is attached to a bracket which is bolted to the chassis. The unit is mounted to the bracket with flexible isolation mounting rubbers which assist in preventing operating noise from being transmitted to the chassis. Air Supply Unit - Depressurization Removal of the air supply unit does not require the whole air suspension system to be depressurized. The front and rear valve blocks and the reservoir valve block are normally closed when de-energized, preventing air pressure in the air springs and the reservoir escaping when the unit is disconnected. Air Supply Unit - System Inhibits There are a number of conditions that will inhibit operation of the air supply unit. It is vitally important that these system inhibits are not confused with a system malfunction. A full list of air supply unit inhibits are given in the air suspension control module section in this workbook. 78 (G538471) Technical Training

80 Lesson 2 Component Description Discovery 3 / LR3 Air Supply Unit Air Supply Unit - Sectioned View Item Description Item Description 1. Exhaust valve cap 11. Isolation rubber mount 2. Plunger 12. Motor assembly 3. Valve seat 13. Crankcase 4. Intake silencer port 14. Crank 5. Delivery valve 15. Crankcase cover 6. Valve guide 16. Connecting rod 7. Cylinder head 17. Piston 8. Drier case 18. Piston exhaust valve 9. Desiccant 19. Spring - pressure relief 10. Pilot exhaust line Technical Training (G538471) 79

81 Discovery 3 / LR3 Lesson 2 Component Description Pilot Exhaust Valve A solenoid operated pilot exhaust valve is connected to the air delivery gallery, downstream of the air drier. The pilot valve, when opened, operates the main compressor exhaust valve. This allows the air springs to be deflated when required. When the solenoid is energized, pilot air moves the exhaust valve plunger, allowing pressurized air from the air springs and/or reservoir to pass via the reservoir control valve to the air supply unit. The solenoid has a resistance value of 4 Ohms at a temperature of 20 C (68 F). Exhaust Valve The exhaust valve has three functions: It operates in conjunction with the pilot exhaust valve to allow air to be exhausted from the air springs and/or the reservoir as described previously The valve protects the system from over-pressure It is connected into the main pressure gallery which is subject to available system pressure in either the air springs or the reservoir The valve is controlled by a spring which restricts the maximum operating pressure to between 319 to 391 lb in² (22 to 27 bar). The minimum pressure in the system is also controlled by the exhaust valve to ensure that, even when deflated, the air springs contain a positive pressure of around 1.0 bar (14.5 lb in²) with respect to atmosphere. This protects the air spring membrane by ensuring it can still 'roll' over the piston without creasing. Electric Motor The electric motor is a 12v dc motor with a nominal operating voltage of 13.5v. The motor drives a crank which has an eccentric pin to which the compressor connecting rod is attached. The motor is fitted with a temperature sensor on the brush PCB assembly. The sensor is connected to the air suspension control module which monitors the temperature and can suspend motor operation if an overheat condition occurs. Compressor The compressor comprises a motor driven connecting rod and piston which operate in a cylinder with a cylinder head. The motor rotates the crank moving the piston up and down in the cylinder bore. The air in the cylinder is compressed with the up stroke and is passed via delivery valve, through the air drier into the system. Air Drier The air drier is an integral part of the air supply unit. The air drier contains a desiccant which absorbs moisture contained in the air. Pressurized air is passed through the air drier desiccant which removes any moisture in the compressed air before it is passed to the reservoir and/or the air suspension system. When the air is exhausted from the system, the returning air is passed back through the air drier, regenerating the air drier by removing moisture from the desiccant and expelling it to atmosphere via the exhaust outlet. The air drier is an essential component in the system ensuring that only dry air is present in the system. If moist air is present in the system, freezing can occur, resulting in poor system operation or component malfunction/failure. 80 (G538471) Technical Training

82 Lesson 2 Component Description Discovery 3 / LR3 Air Reservoir Reservoir Assembly Item Description Item Description 1. Front mounting bracket 3. Air harness connection to reservoir valve block 2. Reservoir 4. Rear mounting bracket The reservoir is an air storage vessel which provides fast air suspension lift times by the immediate availability of pressurized air into the system. The reservoir is a steel fabrication and is located on the outside of the left hand chassis rail, in front of the air supply unit. The reservoir has a bracket at each end which attach to the body mounting brackets on the chassis. The rearward end of the reservoir has a 'Voss' air fitting which provides for the connection of the air hose between the reservoir and the reservoir valve block. The maximum tested pressure of the reservoir is 35 bar (507 lb in²). The pump will cut in when the reservoir pressure drops 1.0 bar (14.5 lb in²) below the nominal pressure setting. Service Reservoirs Reservoirs are supplied to service (and track) at atmospheric pressure, i.e. not pre-charged with a gas element of any kind. The reservoir has a capacity of 9 liters (550 in³). The nominal working pressure of the reservoir is 16.8 bar (243.6 lb in²), with a maximum nominal pressure of 23 bar (333 lb in²). Technical Training (G538471) 81

83 Discovery 3 / LR3 Lesson 2 Component Description Height Sensor Assemblies Front - Height Sensor The sensors are connected via their harness connector to the air suspension control module which receives the signal output from each sensor and, using preprogrammed information, converts the signal to a height for each sensor position. Sensor Identification Ite m Description The front and rear sensors are handed and are colored coded for identification as follows: RH front and rear - black colored lever LH front and rear - white colored lever Rear - Height Sensor Sensor body Drop link Lever arm Electrical connection Height Sensors A height sensor is fitted in each corner of the vehicle to monitor the ride height of the vehicle. The sensor bodies are attached with screws to brackets on the chassis rails. Each sensor comprises a sensor body which contains a single track rotary potentiometer, a lever arm and a drop link. The sensor lever arm has a drop link which provides the connection between the sensor and the suspension control arm. The drop link is a serviceable component and is a push fit to the lever arm and the suspension control arm. 82 (G538471) Technical Training

84 Lesson 2 Component Description Discovery 3 / LR3 Ite Description m 1. Drop link 2. Electrical connection 3. Sensor body 4. Lever arm T4 Calibration A calibration routine is performed using the T4 diagnostic unit. The position of each corner of the vehicle is recorded and the result is recorded in to the ECU memory. Once set, the calibration is not required to be performed unless one of the following occurs: Air suspension control module is removed or replaced Height sensor is removed or replaced Suspension arm to which the sensor is connected is removed or replaced If the removed height sensor is subsequently refitted, the calibration procedure will have to be performed to ensure the integrity of the system. If a replacement drop link is fitted, recalibration is not required providing the sensor body is not removed from its mounting bracket. Air Intake Filter and Silencer Air Intake Assembly Item Description Item Description 1. Exhaust to atmosphere 4. Exhaust air from air supply unit 2. Inlet and exhaust silencer 5. Air inlet supply to air supply unit 3. Air inlet filter Technical Training (G538471) 83

85 Discovery 3 / LR3 Lesson 2 Component Description The air intake filter is connected via a pipe to the intake silencer chamber of the air silencer unit. The filter is located inside the rear left hand corner of the body, away from possible sources of dirt and moisture. The filter contains a foam element which removes particulate matter from the inlet air before it reaches the silencer or the air supply unit. Pipe connections are molded onto each end of the intake silencer and provide for the attachment of the air inlet pipe from the inlet air filter and the air inlet pipe to the air supply unit. The air silencer is required to limit any noise produced from the air supply unit during inflation or deflation of the air springs. The silencer comprises two plastic molded cans, which are bonded together with a silencing foam filling the large internal chamber which forms the exhaust silencer. A pipe connection is molded onto each end of the silencer and provide for the attachment of the exhaust air to atmosphere pipe and the exhaust air pipe from the air supply unit. Air Harness Air Harness - Layout 84 (G538471) Technical Training

86 Lesson 2 Component Description Discovery 3 / LR3 Air Harness Item Description Item Description 1. Front axle valve block 12. Air harness - Main inlet 2. Air harness - Valve block to RHF air spring 13. LHR air spring and damper module 3. RHF air spring and damper module 14. Rear axle valve block 4. LHF air spring and damper module 15. Air harness - Reservoir supply to rear valve block 5. Air harness - Reservoir supply to front 16. Air harness - Compressor air inlet valve block 6. Air harness - Reservoir valve block to 17. Air harness - Compressor air exhaust reservoir 7. Air harness - Exhaust air outlet 18. Air supply unit - Desiccant 8. RHR air spring and damper module 19. Air harness - Air supply unit to reservoir valve block 9. Air harness - Valve block to RHR air spring 20. Reservoir valve block 10. Air silencer assembly 21. Reservoir 11. Air inlet filter 22. Air harness - Valve block to LHF air spring Air Harness Air Harness Diameters PIPE High pressure pipe Compressor inlet Air intake filter to silencer Compressor exhaust Silencer exhaust The air harness consists of ten separate nylon pipes which are connected between the system components with Voss connectors. PIPE DIAMETER 6 mm 8 mm 8 mm 10 mm 19 mm The diameters of the individual pipes are shown in the table above for identification purposes. If a pipe becomes damaged, an in-line connector is available for repair purposes. Technical Training (G538471) 85

87 Discovery 3 / LR3 Lesson 2 Component Description The pipes are secured to the body and chassis via plastic retainer clips. Air Harness Service Air harness Voss connectors can be reused if they are not disturbed from the pipe. Installing Voss connectors to components requires careful observation so as not to cross thread components. Voss connectors should be replaced when a pipe is removed and the old connector discarded. 86 (G538471) Technical Training

88 Lesson 2 Component Description Discovery 3 / LR3 System Control Schematic Control Schematic Technical Training (G538471) 87

89 Discovery 3 / LR3 Lesson 2 Component Description Control Schematic Item Description Item Description 1. Fuse 26E (20 amp) 12. Exhaust valve solenoid 2. Fusible link 11E (30 amp) 13. Air suspension control module 3. Ignition switch 14. Central Junction Box (CJB) 4. Fuse 35P (5 amp) 15. Reservoir control valve 5. Fusible link 10E (60 amp) 16. Air suspension control switch 6. Air supply unit relay 17. Front valve block 7. Fuse 3E (5 amp) 18. Rear valve block 8. Air supply unit 19. RHR height sensor 9. Compressor temperature sensor 20. LHR height sensor 10. Motor 21. RHF height sensor 11. Motor temperature sensor 22. LHF height sensor 88 (G538471) Technical Training

90 Lesson 2 Component Description 2006MY Range Rover (LM) 2006MY Range Rover (LM) Technical Training (G538471) 89

91 2006MY Range Rover (LM) Lesson 2 Component Description Component Review 90 (G538471) Technical Training

92 Lesson 2 Component Description 2006MY Range Rover (LM) Component Description Item Description Air suspension control switch Reservoir RHR damper Rear valve block RHR air spring Reservoir valve block Compressor assembly LHR air spring LHR damper LHR height sensor RHR height sensor Air suspension control module LHF strut assembly LHF height sensor Front valve block RHF height sensor RHF strut assembly System Components The air suspension comprises the following: Two front struts incorporating air springs Two rear air springs Front and rear valve blocks Reservoir valve block incorporating a pressure sensor An air reservoir Four height sensors Air supply unit Air suspension control module Air supply pipes Air suspension control switch. The air suspension system is controlled by the air suspension control module which is located adjacent to the central junction box (CJB), behind the instrument panel. The control module is housed in a plastic bracket attached to the 'A' pillar. Technical Training (G538471) 91

93 2006MY Range Rover (LM) Lesson 2 Component Description Front and rear Valve Blocks Item Description A. B Front valve block Rear valve block Air inlet /outlet to reservoir valve block (Yellow pipe) RHF air spring harness connection (Blue pipe) Isolation rubber mounts Mounting bracket Location slots Electrical connector RHR air spring harness connection (Yellow pipe) Air inlet /outlet to reservoir valve block (Yellow pipe) LHR air spring harness connection (Black pipe) LHF air spring harness connection (Black pipe) 92 (G538471) Technical Training

94 Lesson 2 Component Description 2006MY Range Rover (LM) Valve Blocks Reservoir Valve Block Item Description Air supply unit Electrical connector Air harness connection to reservoir (Black pipe) Air inlet /outlet to rear valve (Blue pipe) Air inlet /outlet to front valve block (Blue pipe with white tape) Air harness connection to air supply unit (Black pipe) Pressure sensor Technical Training (G538471) 93

95 2006MY Range Rover (LM) Lesson 2 Component Description Front and rear Valve Blocks The front and rear valve blocks are similar in their design and construction and control the air supply and distribution to the front or rear pairs of air spring damper modules respectively. The difference between the two assemblies is the connections from the valve block to the left and right hand air spring damper modules and the valve size. It is important that the correct valve block is fitted to the correct axle. Fitting the incorrect valve block will not stop the air suspension system from functioning but will result in slow raise and lower times and uneven raising and lowering between the front and rear axles and may result in misleading DTC'S being set. The front valve block: This is attached to a bracket at the rear of the right hand front wheel arch, behind the wheel arch liner. The valve block has three attachment lugs which are fitted with isolation rubber mounts. Each rubber mount locates in a 'V' shaped slot in the bracket. The rear valve block: This is attached to a bracket at the top of the right hand rear wheel arch, behind the wheel arch liner and adjacent to the fuel filler pipe. The valve block has three attachment lugs which are fitted with isolation rubber mounts which locate in the bracket in three slotted holes. The isolation rubber mounts locate in the 'V' shaped slots and are pulled downwards into positive location in the slots. The front and rear valve blocks: These both have three air pipe connections which use 'Voss' type air fittings. One connection is an air pressure inlet/outlet from the reservoir valve block. The remaining two connections provide the pressure connections to the left and right hand air springs. Each valve block contains three solenoid operated valves; two corner valves and one cross-link valve. Each of the valve solenoids is individually controlled by the air suspension control module. Reservoir Valve Block The four way reservoir valve block is located in the air supply unit sealed housing. The valve block is attached to a bracket at the rear of the air supply unit on three attachment lugs which are fitted with isolation rubber mounts. The isolation rubber mounts locate in the 'V' shaped slots in the bracket and are pulled downwards into positive location in the slots. The valve block controls the storage and distribution of air from the air supply unit and the reservoir and contains an integral system pressure sensor. The valve block has four air pipe connections which use 'Voss' type air fittings. The connections provide for air supply from the air supply unit, air supply to and from the reservoir and air supply to and from the front and rear valve blocks. The connections from the air supply unit and the front and rear control valves are all connected via a common gallery within the valve and therefore are all subject to the same air pressures. The valve block contains a solenoid operated valve which is controlled by the air suspension control module. The solenoid valve controls the pressure supply to and from the reservoir. When energized, the solenoid moves the valve spool allowing air to pass to or from the reservoir. 94 (G538471) Technical Training

96 Lesson 2 Component Description 2006MY Range Rover (LM) The valve block also contains a pressure sensor which can be used to measure the system air pressure in the air springs and the reservoir. The pressure sensor is connected via a harness connector to the air suspension control module. The control module provides a 5V reference voltage to the pressure sensor and monitors the return signal voltage from the sensor. Using this sensor, the control module controls the air supply unit operation and therefore limits the nominal system operating pressure to 17.5 bar (254 lbf/in). The following graph shows nominal pressure values against sensor output voltage. Item Description A. Output voltage (V) B. Pressure (kpa) Removal of the reservoir valve block will require full depressurization of the air suspension system. The valve block is a non-serviceable item and should not be disassembled other than for replacement of the pressure sensor. Valve Block Solenoid Specifications Description Value Coil resistance at 2.05 Ohms ± 10% 20 C (68 F) NOTE: Resistance values will vary with coil temperature. Resistance of test leads must be measured before any readings are taken. Resistance value of the test leads must be subtracted from final solenoid resistance value. Technical Training (G538471) 95

97 2006MY Range Rover (LM) Lesson 2 Component Description Air Supply Unit Item Description Cover Motor electrical connector Reservoir valve block Pilot air pipe Secondary silencer 96 (G538471) Technical Training

98 Lesson 2 Component Description 2006MY Range Rover (LM) Item Description Air drier Base plate Rubber mounts Exhaust valve Intake pipe Exhaust silencer Air harness to front valve block Air harness to reservoir Air harness to rear valve block Secondary silencer Pilot exhaust valve Solenoid and sensors electrical connection The air supply unit fitted from 2006MY is an improved unit providing quieter operation. Two silencer units are incorporated into the unit assembly to reduce operating noise. The air supply unit is located in a housing which is mounted in the spare wheel well and secured with four bolts into threaded inserts to the vehicle floorpan. The unit is isolated from the vehicle body via four rubber isolation mounts. The reservoir valve block is also located within the housing on a separate bracket at the rear of the unit. The unit is connected to the system via a single air pipe to the reservoir valve block. Three air pipes from the reservoir valve block pass through an aperture in the unit housing and through a grommet in the wheel well. It is important to ensure that this grommet is not disturbed and correctly installed. Incorrect fitment will allow water to enter the wheel well leading to possible damage to and failure of the air supply unit. The unit comprises a piston compressor, a 12V electric motor, a solenoid operated exhaust pilot valve, a pressure relief valve, an air drier unit and two silencers. The electric motor, compressor, air drier and pressure limiting and exhaust valve are mounted on a frame which in turn is mounted on flexible rubber mountings to reduce operating noise. The unit is mounted on a pressed base plate which is located on the floor of the wheel well. The unit is protected by a pressed cover which is lined with an insulating foam further limiting the operating noise. The air supply unit can be serviced in the event of component failure, but is limited to the following components; air drier, pilot exhaust pipe and the rubber mounts. Technical Training (G538471) 97

99 2006MY Range Rover (LM) Lesson 2 Component Description Removal of the air supply unit does not require the whole air suspension system to be depressurized. The front and rear valve blocks and the reservoir valve block are normally closed when de-energized, preventing air pressure in the air springs and the reservoir escaping when the unit is disconnected. There are a number of conditions that will inhibit operation of the air supply unit. It is vitally important that these system inhibits are not confused with a system malfunction. A full list of air supply unit inhibits are given in the air suspension control module section in this chapter. Item Description Exhaust valve cap Plunger Valve seat Intake silencer port Delivery valve Valve guide Cylinder head Drier case 98 (G538471) Technical Training

100 Lesson 2 Component Description 2006MY Range Rover (LM) Item Description Desiccant Pilot air pipe Isolation rubber mounts Motor assembly Crankcase Crank Crankcase cover Connecting rod Piston Pilot exhaust valve Spring - slave valve (pressure relief) Electric Motor The electric motor is a 12V dc motor with a nominal operating voltage of 13.5V. The motor drives a crank which has an eccentric pin to which the compressor connecting rod is attached. The motor is fitted with a temperature sensor on the brush Printed Circuit Board (PCB) assembly. The sensor is connected to the air suspension control module which monitors the motor temperature and can suspend motor operation if the operating thresholds are exceeded. Motor Operating Temperatures Leveling Reservoir Filling OFF 140 C 130 C (266 C) (284 F) ON 120 C (248 F) 110 C (230 F) The following graph shows motor temperature sensor resistance values against given temperatures. NOTE: This graph is also applicable for the compressor cylinder head temperature sensor. The following table shows the control module operating parameters for the differing air supply unit functions and the allowed motor operating temperatures. Technical Training (G538471) 99

101 2006MY Range Rover (LM) Lesson 2 Component Description Brush Temperature and Resistance Item Description A. B. Resistance (kohms) Temperature ( C) The following graph shows air suspension control module output voltages against motor temperature sensor temperatures. NOTE: This graph is also applicable for the compressor cylinder head temperature sensor. 100 (G538471) Technical Training

102 Lesson 2 Component Description 2006MY Range Rover (LM) Compressor Temperature and Sensor Voltage Item Description A. B. Control module input voltage (V) Temperature sensor ( C) Compressor The compressor is used to supply air pressure to the air suspension reservoir. The air suspension control module monitors the pressure within the reservoir and, when the engine is running, maintains a pressure of 17.5 bar (254 lbf/in). The compressor comprises a motor driven connecting rod and piston which operate in a cylinder with a separate cylinder head. The motor rotates the crank moving the piston up and down in the cylinder bore. The air in the cylinder is compressed with the up stroke and is passed via the delivery valve through the air drier and the silencers into the system. The cylinder head is fitted with a temperature sensor. The sensor is connected to the air suspension control module which monitors the cylinder temperature and can suspend motor and compressor operation if an overheat condition occurs. The following table shows the control module operating parameters for the differing air supply unit functions and the allowed compressor cylinder head operating temperatures. Technical Training (G538471) 101

103 2006MY Range Rover (LM) Lesson 2 Component Description Compressor Cylinder Head Operating Temperatures Leveling Reservoir Filling OFF 150 C (302 F) 140 C (284 C) ON 130 C (266 F) 120 C (248 F) Refer to the motor temperature sensor graph for compressor cylinder head temperature sensor resistance values and the air suspension control module output voltage / temperature sensor graph. Air Drier Attached to the compressor is the air drier which contains a desiccant for removing moisture from the compressed air. Pressurized air is passed through the air drier which removes any moisture in the compressed air before it is passed into the reservoir and/or the system. When the air springs are deflated, the exhaust air also passes through the air drier, removing the moisture from the unit and regenerating the desiccant. The air drier is an essential component in the system ensuring that only dry air is present in the system. If moist air is present, freezing can occur resulting in poor system operation or component malfunction or failure. Pilot Exhaust Valve Attached to the end of the air drier unit is a solenoid operated exhaust pilot valve. This valve is opened when the air springs are to be deflated. When the solenoid is energized, pilot air moves the exhaust valve plunger, allowing pressurized air from the air springs and/or the reservoir to pass through the air drier to atmosphere. Exhaust Valve The exhaust valve operates when the pilot exhaust valve is opened, allowing air returning from the air springs and/or the reservoir to be exhausted quickly. The pilot exhaust valve also provides the system pressure relief function which protects the air springs from over inflation. The valve is pneumatically operated, responding to air pressure applied to it to overcome pressure from its internal spring. The valve is connected into the main pressure gallery which is always subject to the system pressure available in either the air springs or the reservoir. The valve is controlled by a spring which restricts the maximum operating pressure to between 22 to 27 bar (319 to 391 lbf/in). The minimum pressure in the system is also controlled by the exhaust valve to ensure that, even when deflated, the air springs contain a positive pressure with respect to atmosphere. This protects the air spring by ensuring it can still 'roll' over the piston without creasing. Air Supply Unit Specifications Description Value Working pressure 14.5 bar The pilot exhaust valve is connected to the air delivery gallery, downstream of the air drier. The pilot valve, when opened, operates the compressor exhaust valve allowing the air springs to be deflated. Maximum pressure (stabilized) Operating voltage 22.0 to 27.0 bar 10 to 16.5 Volts (13.5 Volts nominal) 102 (G538471) Technical Training

104 Lesson 2 Component Description 2006MY Range Rover (LM) Description Running current consumption Maximum start-up current Pilot Exhaust Valve - Solenoid valve resistance at 20 C (68 F) Value Amps depending on load 120 Amps 4 Ohms ± 10% NOTE: Resistance values will vary with coil temperature. Resistance of test leads must be measured before any readings are taken. Resistance value of the test leads must be subtracted from final solenoid resistance value. There are a number of conditions that will inhibit operation of the air suspension compressor. It is vitally important that these inhibits are not confused with a system malfunction. A full list of compressor inhibits is contained in the Principles of Operation section. Reservoir Technical Training (G538471) 103

105 2006MY Range Rover (LM) Lesson 2 Component Description Item Description Reservoir mounting screw - front Reservoir mounting screw - rear Reservoir The reservoir is an air storage vessel which provides fast air suspension lift times by the immediate availability of pressurized air into the system. The reservoir is located under the RH sill of the vehicle and is fabricated from steel and secured with four bolts to the underside of the vehicle. The reservoir supplies pressurized air to the four air springs, via the valve blocks, to enable the air suspension system to carry out ride height changes. The rearward end of the reservoir has a 'Voss' air fitting which provides for the connection of the air hose between the reservoir and the reservoir valve block. The reservoir has a capacity of 10.2 liters (622 in). The nominal working pressure of the reservoir is 14.4 to 15.5 bar (209 to 224 lbf/in), with a maximum pressure of 22 bar (319 lbf/in). Height Sensors Item Description Front sensor bracket Fixings Rear sensor bracket Electrical connector 104 (G538471) Technical Training

106 Lesson 2 Component Description 2006MY Range Rover (LM) Item Description Sensor Lever arm and drop link Securing nut A height sensor is fitted in each corner of the vehicle to monitor the ride height of the vehicle. The sensors are mounted on the front and rear subframes, with a mechanical link to the suspension lower arms. There are four different types of sensor fitted. The front and rear sensors are handed and are colored coded for identification as follows: Right hand front and rear - black colored lever Left hand front and rear - white colored lever If a height sensor is removed from its mounting position for servicing or replacement, T4 must be used to re-calibrate the system. Calibration will also be required if the suspension arm to which the sensor is connected is removed or replaced or if a replacement drop link is fitted. A calibration routine is performed using T4 to read the position of each corner of the vehicle and record the settings in the control module memory. Once set, the calibration is not required to be performed unless the air suspension control module is removed or replaced, a height sensor is removed or replaced or a suspension arm to which the sensor is connected is removed or replaced. If the removed height sensor is subsequently refitted, the calibration procedure will have to be performed to ensure the integrity of the system. The height sensors are attached to brackets on the subframes and are connected to the lower arms by links. The links allow articulation of the arm to allow for suspension travel. Each sensor is connected by a six pin multiplug. The front and rear sensor drop links are serviceable items. Each sensor comprises a sensor body which contains a single track rotary potentiometer, a lever arm and a drop link. The sensor is supplied with a reference voltage from the air suspension control module which measures the returned voltage to determine the sensor arm position. Front Height Sensor On the front height sensors the voltage decreases as the vehicle height increases. On the rear sensors the voltage increases as the vehicle height increases. The sensors can be checked by applying 5V across the positive and negative terminals and measuring output signal which should be a nominal 57mV ± 3% per degree of sensor arm movement. The following graph shows the vehicle height displacement from normal against output voltage for the front height sensors. The center line represents the "nominal" condition but depending on tolerances, the actual line may lie anywhere between the upper and lower lines. Technical Training (G538471) 105

107 2006MY Range Rover (LM) Lesson 2 Component Description Item Description A. B. Volts (V) Displacement from normal height (mm) Rear Height Sensor The following graph shows the vehicle height displacement from normal against output voltage for the rear height sensors. The center line represents the "nominal" condition but depending on tolerances, the actual line may lie anywhere between the upper and lower lines. 106 (G538471) Technical Training

108 Lesson 2 Component Description 2006MY Range Rover (LM) Item Description A. B. Volts (V) Displacement from normal height (mm) Technical Training (G538471) 107

109 2006MY Range Rover (LM) Lesson 2 Component Description Air Springs Item Description Cover Seal plate Securing nut Front air spring Air pipe connection Rear air spring The air springs on the front and rear suspension are similar in construction. The air springs are manufactured from a flexible rubber and each air spring forms an air tight cavity which provides the required spring rate for each corner of the vehicle. As the air spring is compressed, the rubber material compresses and rolls down the side of the vertical housing (piston) below the spring. An air connection port is located on the top of each spring and allows air to be added or removed from each spring. 108 (G538471) Technical Training

110 Lesson 2 Component Description 2006MY Range Rover (LM) The port is connected via a Voss connector and a plastic tube to the valve block on the reservoir. Replacement of an individual air spring does not require a full depressurization of the air suspension system. Only the corner concerned need be depressurized. When servicing of an air spring or a full system depressurization is required, the weight of the vehicle must be supported before the system is depressurized. On reassembly, the air spring must be fully pressurized before the weight of the vehicle is applied to it. This is achieved using a routine in T4. Air Harness Item Description Main harness Rear valve block to LHR air spring Rear valve block to RHR air spring Front valve block to LHF air spring Front valve block to RHF air spring Technical Training (G538471) 109

111 2006MY Range Rover (LM) Lesson 2 Component Description The system is interconnected via 6 mm diameter blue, yellow and black colored nylon pipes. The yellow pipes denote the right hand side and the black pipes denote the left hand side. Blue colored pipes are used to show the pipes which connect the front and rear valve blocks to the reservoir valve. The air harness comprises a main harness which is located along the full length of the vehicle and connects the reservoir valve block to the front and rear valve blocks and the reservoir and four separate harnesses which are used to connect each valve block to the air springs. The pipes are attached to the subframes and vehicle body with clips. To ensure that the correct routing is maintained, the pipes have timing marks which align with various clip positions. The timing marks are in the form of a white band around the pipe, indicating the clip position. If the correct routing is not achieved, unnecessary tension at the pipe joints will occur resulting in possible early failure. If a pipe becomes damaged, an in-line connector is available for repair purposes. The pipes are secured to the body and the chassis with a number of plastic clips. If the vehicle appears to be leaking, perform a leak check on all aspects of the system, i.e.; air spring hose fittings and the associated connections on the valve blocks, air springs and reservoir. Failure to correctly diagnose leakage will result in unnecessary exchange of serviceable components and recurrence of original problem. Air Suspension Control Module The air suspension system fitted to Range Rover is controlled by the air suspension control module which is located adjacent to the passenger compartment fusebox, behind the instrument panel. The control module is housed in a plastic bracket attached to the 'A' pillar. The control module monitors the height of each corner of the vehicle via four height sensors, which are mounted in-board of each road wheel. The control module has the following modes of operation: Calibration Normal Periodic Wake-Up. When a new air suspension control module is fitted, the air suspension system will not function until the air suspension software is loaded and the system calibrated with T4. Leak Detection Leak detection can be carried out using a Land Rover approved leak detection spray. Leak detection spray part number: STC 1090 (GOTEC LDS). Module Calibration A calibration routine is performed using T4 to access the position of each corner of the vehicle and record the settings in the control module memory. Once set, the calibration is not required to be performed unless any of the following occurs: The air suspension control module is removed or replaced. 110 (G538471) Technical Training

112 Lesson 2 Component Description 2006MY Range Rover (LM) A height sensor or bracket is removed, replaced or disturbed. The suspension arm to which the sensor is connected is removed or replaced. If the removed height sensor is subsequently refitted, the calibration procedure will have to be performed to ensure the integrity of the system. If the air supply unit, the reservoir, a valve block, a damper module or the air harness is removed or replaced, the system will not require recalibration. Wake-Up Mode When the vehicle is parked, the air suspension control module 'wakes up' two hours after the ignition was last switched off and then once every six hours thereafter. The vehicle height is checked and if the vehicle is not level within a pre-set tolerance, small downwards height adjustments may be made automatically. Air Suspension Control Module Harness Connectors Item Description Air suspension control module Connector C2321 Connector C2030 Connector C2320 Connector C0867 Technical Training (G538471) 111

113 2006MY Range Rover (LM) Lesson 2 Component Description Connector C2030 Pin No to Description Rear control valve - Cross link valve - Positive (+) Not used Not used Not used Air supply unit - Motor temperature sensor signal Not used Air supply unit - Motor temperature sensor - Ground Not used Switch pack display - Height change LED Switch pack display - On-road mode LED Rear control valve - Cross link valve - Negative (-) Not used Gateway wake-up signal Not used Switch pack display - Crawl mode LED Switch pack display - Access mode LED Driver door module access switch Switch pack - Raise switch signal Input/Output Output Input - Input - Output Output Input - Output - Output Output Input Input Connector C2320 Pin No Description Air supply unit voltage signal input from air supply unit relay Reservoir control valve - Pressure sensor - 5 Volt supply Reservoir control valve - Pressure sensor - Signal Reservoir control valve - Pressure sensor - Ground Input/Output Input Output Input Input 112 (G538471) Technical Training

114 Lesson 2 Component Description 2006MY Range Rover (LM) Pin No and 8 Description Air supply unit - Exhaust valve - Negative (-) Air supply unit - Exhaust valve - Positive (+) Not used Input/Output Input Output - Connector C2321 Pin No to Description 12V Permanent battery supply Compressor temperature sensor - Signal Front LH height sensor - 5 Volt supply Front LH height sensor - Signal Front LH height sensor - Ground Air supply unit relay coil - Positive Air supply unit relay coil - Ground Reservoir control valve coil - Positive (+) Front control valve - RH corner valve - Negative (-) Front control valve - RH corner valve - Positive (+) Front control valve - LH corner valve - Negative (-) Front control valve - LH corner valve - Positive (+) Switch pack - Hold switch signal Front RH height sensor - 5V supply Front RH height sensor - Signal Front RH height sensor - Ground Compressor temperature sensor - Ground Not used Reservoir control valve coil - Negative (-) Front control valve - cross link valve - Positive (+) Front control valve - cross link valve - Negative (-) Permanent ground supply Input/Output Input Input Output Input Input Output Input Output Input Output Input Output Input Output Input Input Input - Input Output Input Input Technical Training (G538471) 113

115 2006MY Range Rover (LM) Lesson 2 Component Description Connector C0867 Pin No. Description Input/Output and Rear control valve - LH corner valve positive (+) Rear control valve - LH corner valve negative (-) Not used Switch pack - Lower switch signal Rear LH height sensor - 5 Volt supply Rear LH height sensor - Signal Rear LH height sensor - Ground Rear RH height sensor - 5 Volt supply Rear RH height sensor - Signal Rear RH height sensor - Ground Rear control valve - RH corner valve positive (+) Rear control valve - RH corner valve negative (-) Air suspension control - GEM signal (wake-up) Switch pack display - LED negative Switch pack display - off-road mode LED CAN IN positive (+) - High Not used CAN IN negative (-) - Low 12 Volt ignition switch supply Output Input - Input Output Input Input Output Input Input Output Input Input Input Output Input - Input Input 114 (G538471) Technical Training

116 Lesson 3 Principles of Operation Objectives On completing this lesson, you will be able to: Describe the principles of air suspension operation Operate the system control switches to obtain the desired vehicle condition fit for the purpose. Technical Training (G538474) 115

117 Range Rover (LP) Lesson 3 Principles of Operation RANGE ROVER (LP) System Control All driver related controls are situated in the center of the fascia. Control Switch Panel Height control switch Inhibit switch The height control is a rocker type switch used by the driver to select the required vehicle ride height. Height Changes NOTE: The vehicle will not respond to switch inputs until the switch is released. All changes to vehicle ride heights are indicated to the driver by the ride height indicator lamps located next to the switch. Switch Panel The inhibit switch is a mechanical latching switch and is used to modify the automatic ride height system changes. The switch panel consists of the following: 116 (G538473) Technical Training

118 Lesson 3 Principles of Operation Range Rover (LP) Selection of the inhibit switch function is indicated to the driver by the illumination of a tell-tale LED located in the switch. The LED is bulb tested with the ride height indicator lamp. Indicator Lamps Between the height control rocker switch and the latching inhibit switch is the indicator warning lamp panel. This panel has the following indicator lamps: High profile Standard height Low profile Access mode Two other driver indicator lamps are: Instrument warning lamp Inhibit mode tell-tale light Indicator and Tell-Tale Indicator & Tell-Tale Lamps With the ignition key turned to position 2, all four indicator lamps, the air suspension warning light and the inhibit switch lamp will be illuminated continuously. When the engine is started, the lights will remain illuminated for 2 seconds, after which the current ride height setting will be displayed. Two indicator lights will illuminate when the vehicle is between ride heights, with the selected ride height lamp flashing. When the selected height is achieved the indicator lamp will be illuminated constantly and the previously selected ride height indicator lamp will be extinguished. The inhibit lamp is illuminated while it is activated, i.e. inhibit switch latched results in the LED being switched-on. Both switches are illuminated with the side light switched on. Additional driver information is provided by the message center in the instrument cluster. Instrument Cluster Warning An amber air suspension warning lamp is located in the instrument cluster. Technical Training (G538473) 117

119 Range Rover (LP) Lesson 3 Principles of Operation Instrument Cluster The warning lamp will be constantly illuminated when driving at high ride height profile and will flash when the vehicle is at extended ride height. The lamp will also illuminate when a fault within the air suspension system has been detected. Low ride height Access height with Crawl mode Height Settings A bulb check function is provided when the ignition is turned to position 2, and for 2 seconds after the engine is started. Height Profile Description Electronic Air Suspension (EAS) provides five different height settings, including an 'Access' mode. Ride Heights Available Extended ride height High ride height Standard ride height These settings when chosen will either increase or decrease the vehicle ride height to ground clearance to cope with the differing driving conditions. 118 (G538473) Technical Training

120 Lesson 3 Principles of Operation Range Rover (LP) EAS Inhibits Requested ride height changes will NOT take place if any of the following are active: Tailgate open Any door open Foot brake continuously applied for less than 3 minutes Engine not running The engine not running inhibit has an exception for Access height selection within 40 seconds of switching the ignition off. WARNING: Frequent changes between ride height could cause the air supply compressor to overheat. NOTE: If the compressor overheats, the system will cease activity and will resume full operational status again within a few minutes once the compressor has cooled. If Access mode is required, ensure the handbrake is applied and select 'P' for automatic transmissions variants. Standard Ride Height With the inhibit switch in the off position (un-latched) and at speeds below 50 mph (80 km/h) the standard ride height indicator will be illuminated. Standard Height Symbol Maintaining the vehicle ride height under all load conditions assists in maintaining correct headlamp leveling. Low Ride Height Description Low ride height is automatically selected when the vehicle speed exceeds 50 mph (80 km/h) for at least 30 seconds with the inhibit switch in the off position (un-latched). Low Height Symbol The low ride height indicator will flash during the height change and the standard ride height indicator will extinguish when the low ride height profile has been attained. Standard ride height is automatically selected when the vehicle speed drops below 35 mph (56 km/h) for at least 30 seconds with the inhibit switch in the off position (un-latched). The driver can select low ride height at any speed. With the vehicle at the low ride height setting, depressing the inhibit switch (latched) will result in the vehicle maintaining ride height regardless of speed. Access Ride Height This feature is used to make access to and from the vehicle much easier. Access Ride Height Symbol The standard vehicle ride height will be maintained under all load conditions. Technical Training (G538473) 119

121 Range Rover (LP) Lesson 3 Principles of Operation A number of conditions need to be completed in order to permit the vehicle to descend in to access mode. The following are conditions that need to be met: Vehicle stationary Doors closed Tailgate closed Park brake applied Foot brake released Park selected (automatics) Switch pressed down and released While the vehicle is descending, the access indicator lamp will flash. The standard indicator lamp will flash during the height change. When standard ride height is attained the indicator will remain constantly illuminated and the access indicator lamp will be extinguished. Crawl Mode In areas where height is restricted, the vehicle may be driven in access mode, however this mode is then renamed crawl mode. Crawl (Access) Mode Symbol When access mode is attained, the indicator lamp will remain constantly illuminated. The standard ride height lamp will be extinguished. Access mode can be selected up to 40 seconds before stopping the vehicle, i.e. approaching residential driveway in readiness to stop and park the vehicle. NOTE: It is possible to select access mode up to 40 seconds after switching the engine off. NOTE: Opening a door or tailgate will immediately stop the vehicle height changes. When the door is closed, the height change will then be completed. If the door is opened for more than 30 seconds, the system will need reminding of the required height when the door or tailgate is closed. On stopping the vehicle, applying the park brake, releasing the foot brake and selecting park (automatics), the vehicle will lower to the requested access mode ride height. Driving the vehicle will result in an automatic return to standard ride height. Alternatively standard ride height can be achieved by closing all doors, starting engine and pressing the up switch. To achieve crawl mode ensure the inhibit switch is un-latched and select access mode. When access ride height is achieved, press the inhibit switch. The inhibit switch indicator will be illuminated to show it has been selected. The message center in the instrument pack will beep three times and display 'EAS MANUAL'. The vehicle may now be driven at speeds up to 20 mph (32 km/h). If the vehicle is accelerated to 10 mph (16 km/h), the message center will beep three times and display 'SLOW 20 MPH MAX'. If the vehicle speed exceeds 25 mph (40 km/h), the vehicle will rise to low profile, with low warning flashing. On slowing down to 20 mph (32 km/h), the vehicle will lower to access mode height with the access warning indicator illuminated. 120 (G538473) Technical Training

122 Lesson 3 Principles of Operation Range Rover (LP) When the vehicle speed falls below 5 mph (8 km/h), the message center will beep three times and display 'EAS MANUAL'. To cancel Crawl Mode, release the inhibit switch or depress the up switch. High Ride Height This mode is used to improve approach and departure angles and also to improve the characteristics of the vehicle when wading. High Lock mode is indicated by the warning LED's flashing in sequence from the bottom upwards. The T4 diagnostic equipment is required to activate and deactivate 'High Lock' mode. Extended Ride Height This mode is activated if the chassis is grounded leaving a wheel or wheels unsupported. Extended Height Symbol High Mode Symbol When at standard ride height, pressing the up switch will select the High Ride Height profile providing the vehicle road speed is below 35 mph (56 km/h). The high ride height indicator lamp will flash during the height change. When the change is complete the indicator lamp will remain constantly illuminated, and the standard ride height indicator lamp will be extinguished. The amber air suspension indicator lamp in the instrument pack will also be illuminated. If the road speed exceeds 35 mph (56 km/h), the vehicle will return to the standard ride height profile. High Lock Mode The vehicle can be placed in to a safety condition, known as 'High Lock' mode. High Lock mode permits the vehicle to be worked on without the system operating. Thus making the vehicle safe to work on, i.e. the system locks out the controls etc. The first initial ECU reaction is to lower (deflate) the affected air springs. After a timed duration, if the ECU has not detected a height change, it will re-inflate the air springs to an extended height in an attempt to regain traction. This position will be held for 10 minutes, after which the vehicle will automatically return to standard ride height. WARNING: If the vehicle speed exceeds 35 mph (56 km/h), the vehicle will immediately lower to the standard ride height position. This speed could be achieved for example by a wheel spin type conditions. Alternatively, pressing the ride level control switch down will lower the vehicle 20 mm to the high profile height. Transportation Review Vehicles leaving the factory are transported with the EAS system electronically frozen in the access mode condition. Technical Training (G538473) 121

123 Range Rover (LP) Lesson 3 Principles of Operation When the road speed exceeds 25 mph (40 km/h), the vehicle will rise to Low Ride Height. It will return to access mode height if the speed falls below 24 mph (38 km/h). This condition is cancelled at the PDI (Pre Delivery Inspection) stage by entering the appropriate commands using the T4 diagnostic equipment. WARNING: When an air suspension vehicle is secured to a transporter using the chassis lashing eyes, there is a possibility that the securing strap tension could be lost. This is due to the following conditions occurring: Air leakage Self-leveling operation Operation of the ride height controls PRECAUTION: To prevent this occurrence from happening the ride height should be set to access mode before securing to the transporter. NOTE: If the engine cannot be run and the vehicle is not in access mode, the vehicle can still be transported. However, the vehicle must be secured to the transporter by the road wheels and not the chassis lashing eyes. As an indication that the vehicle is in Transportation mode, the LED's flash in sequence from the top downwards. Transportation mode can be activated and deactivated only by the T4 diagnostic equipment. 122 (G538473) Technical Training

124 Lesson 3 Principles of Operation Range Rover (LP) EAS System Review Air Suspension Schematic EAS Operating Review Air is drawn in through the compressor inlet filter (1) to the compressor (2), where it is compressed to 10 bar (145 psi). Compressed air passes to the air drier unit (3) where moisture is removed as it flows through the desiccant. Dried air passes through non-return valve NRV1 to the air supply reservoir (4). The 3 non-return valves: NRV1, NRV2 and NRV3 (6) are used to ensure correct air flow. These non-return valves also prevent loss of spring air pressure if a total loss of reservoir pressure occurs. The green pressure switch (5) maintains system pressure between set limits by switching the compressor on and off via an ECU controlled relay. For air to enter an air spring (10), the inlet valve (7) must be energized together with the relevant air spring solenoid (9). For air to be exhausted from an air spring (10), exhaust valve (8) must be energized together with the relevant air spring solenoid (9). All exhausted air passes through the air drier unit which purges moisture from the desiccant and regenerates the drier. Air is finally exhausted through an air operated diaphragm valve (12) to atmosphere via a silencer (13) mounted below the valve block assembly. A pressure relief valve (11) is fitted and can be identified by its brass color and its location next to the green pressure switch (5) on the valve block. Technical Training (G538473) 123

125 Range Rover (LM) Lesson 3 Principles of Operation RANGE ROVER (LM) 124 (G538473) Technical Training

126 Lesson 3 Principles of Operation Range Rover (LM) System Control Air Suspension ECU The air suspension ECU monitors the vehicle ride height through the use of four non contact type Hall effect height sensors up to VIN and from VIN , four single track potentiometer type sensors. The ECU has three modes of operation: Normal Periodic wake-up Transportation When a service replacement air suspension ECU is fitted, the air suspension system will not function until configured with T4 diagnostic equipment. Normal Mode The air suspension ECU will enter normal mode when it receives a 'wake-up' signal from the Body Control Unit (BCU). The BCU, located under the passenger front seat will provide the 'wake-up' signal when the following occurs: A door is opened Vehicle is remote unlocked The ignition is switched on The BCU will continue to supply the 'wake-up' signal for 15 minutes after the ignition is switched off. Technical Training (G538473) 125

127 Range Rover (LM) Lesson 3 Principles of Operation The air suspension ECU will then remain active for a further seconds to enable any new data to be written to its Electronic Erasable Programmable Read Only Memory (EEPROM). If the air pressure is less than 9 bar (130 psi) the compressor is used for height changes. Filling of the reservoir remains inhibited as per ignition off status. System Wake-Up If the BCU has supplied a 'wake-up' signal, but the ignition is in the off position, the air suspension ECU will enter an Inactive Mode. Under these circumstances, air suspension functionality is reduced. However, the air suspension ECU will continue to monitor vehicle ride height and make any necessary adjustments. All ride height selections made by the rotary switch will be ignored and therefore the ECU will not illuminate the LED's or allow the compressor to fill the reservoir. However, if the pressure in the air reservoir falls below 9 bar (130 psi) the ECU will power the compressor to raise the vehicle to the current height. Ignition On If the ignition is switched on but the engine is not running, the air suspension ECU will continue to monitor vehicle ride height and make any necessary adjustments. Downward ride height selections made via the rotary switch will be accepted, and the LED's will illuminate as normal. Upward ride height selections made via the rotary control switch will be rejected, but the ECU will allow the vehicle height to increase to return the vehicle to the current ride height, e.g. if a load has been added to the vehicle. These height changes are made using the air suspension reservoir providing the available air pressure is more than 9 bar (130 psi). Periodic 'wake-up' Mode When the 'wake-up' signal is removed by the BCU, the air suspension ECU powers down. The air suspension ECU will wake-up approximately every six hours and level the vehicle height if required. The air suspension ECU will determine which corner is lowest and adjust the remaining corners to the same level. This action takes approximately 6 10 seconds to perform. The air suspension ECU will then remain active for further seconds to enable any new data to be written to its EEPROM. NOTE: The air suspension ECU will not raise the vehicle during the wake-up mode. If the air suspension ECU fails to level the vehicle, i.e. an obstruction beneath the vehicle for example, the periodic 'wake-up' mode will be suspended until the air suspension ECU receives a 'wake-up' signal from the BCU. Transportation Mode To enable the vehicle to be delivered safely from the factory to the dealership, the air suspension system is set in transportation mode. When the engine is running, the ride height will be set at 'Transportation High', (this is the same as standard ride height). All four LED's will illuminate in a sequence being at the top and travel downwards to indicate that Transport mode is active. 126 (G538473) Technical Training

128 Lesson 3 Principles of Operation Range Rover (LM) When the engine is not running, the air suspension ECU will drop the ride height by 60 mm to 'Transportation Low'. When the ride height is at 'Transportation Low' the vehicle can be lashed to a transporter, without the risk of straps loosening due to ride height lowering. Transportation Low is 20 mm below access mode at 680 mm Vehicle Height Table Speed Height Mode Vehicle Height Comments <31 mph (49 km/h) Off-Road Height Front 800 mm Fronts up 60 mm Rear 790 mm Rears up 50 mm Standard Height 740 mm Also used for Transport High Mode >62 mph (>99 km/h) Motor way Height 720 mm Reduction of 20 mm from Standard Ride Height (this is also the Default Ride Height) Access Height 700 mm Reduction of 40 mm from Standard Ride Height Transport High 740 mm Same as Standard Ride Height Transport Low 680 mm Reduction of 60 mm from Standard Ride Height Technical Training (G538473) 127

129 Range Rover (LM) Lesson 3 Principles of Operation ECU Harness Connectors ECU Connectors NOTES: Pin Out Information Chart DO NOT BACK PROBE SEALED CONNECTORS OR PIERCE WIRING INSULATION TO TAKE ANY VOLTAGE MEASUREMENT READINGS Pin Out Data - C0867 Pin No Description Input or Output Voltage Reading 1 Not used CAN bus 'high' Input/Output 2.5v 3 Control switch up selection Input 12v /0v 4 Control switch hold selection Input 12v /0v 128 (G538473) Technical Training

130 Lesson 3 Principles of Operation Range Rover (LM) Pin No Description Input or Output Voltage Reading 5 Control switch Motor way ride height Output 4.0v /1.4v LED 6 RHF corner valve control Input Gnd 7 RHF and LHF corner valves power Output 12v supply 8 LHF corner valve control Input Gnd 9 RHR corner valve control Input Gnd 10 RHR and LHR corner valve power Output 12v supply 11 LHR corner valve control Input Gnd 12 Reservoir control valve Input Gnd 13 Reservoir valve power supply Output 12v 14 Exhaust pilot valve power supply Output 12v 15 Exhaust pilot valve control Ground Gnd 16 Air suspension relay control Output 12v 17 High pressure exhaust valve power Output 12v supply 18 Not used Not used Not used 19 Not used Not used Not used 20 CAN bus 'low' Input/Output 2.5v 21 Control switch down selection Input 12v /0v 22 Control switch off-road ride height Output 4.0v /1.4v LED 23 Control switch access ride height Output 4.0v /1.4v LED 24 RHF height sensor signal Input 0.5v /4.5v 25 LHF height sensor signal Input 0.5v /4.5v 26 RHR height sensor signal Input 0.5v /4.5v 27 LHR height sensor signal Input 0.5v /4.5v Technical Training (G538473) 129

131 Range Rover (LM) Lesson 3 Principles of Operation Pin No Description Input or Output Voltage Reading 28 Air pressure sensor signal Input 0.5v /4.5v 29 Not used Not used Not used 30 Not used Not used Not used 31 Temperature sensor Output 12v O/C 22 C) 32 LHF height sensor power supply Output 5v 33 RHF height sensor power supply Output 5v 34 Air pressure sensor power supply Output 5v 35 High pressure exhaust valve control Ground Gnd 36 Not used Not used Not used 37 'K' bus Input/Output 12v 38 Wake-Up signal Input 12v /0v (time period) 39 Ride height switch (driver's door Input 12v /0v module) 40 Control switch standard ride height Output 4.0v /1.4v LED 41 Control switch inhibit LED illumina- Output 4.0v /1.4v tion 42 RHF height sensor ground Ground Gnd 43 LHF height sensor ground Ground Gnd 44 RHR height sensor ground Ground Gnd 45 LHR height sensor ground Ground Gnd 46 Air pressure sensor ground Ground Gnd 47 Not used Not used Not used 48 Not used Not used Not used 49 Temperature sensor ground Ground Gnd 50 RHR height sensor power supply Output 5v 51 LHR height sensor power supply Output 5v 52 Gnd Gnd Gnd 130 (G538473) Technical Training

132 Lesson 3 Principles of Operation Range Rover (LM) Pin Out Information Chart Pin Out Data - C2030 Pin No Description Input or Output Voltage Reading 1 Not used Not used Not used 2 Front cross link valve ground Ground Gnd 3 Rear cross link valve ground Ground Gnd 4 Not used Not used Not used 5 Ground Ground Gnd 6 Not used Not used Not used 7 Rear cross link power supply Output 12v 8 Front cross link power supply Output 2v 9 Not used Not used Not used 10 Battery power supply Input 12v Technical Training (G538473) 131

133 Range Rover (LM) Lesson 3 Principles of Operation Operating Modes Control Switch Item Description Ride height selector Ride height selector indicator panel Suspension inhibit switch Drivers door Access Switch 132 (G538473) Technical Training

134 Lesson 3 Principles of Operation Range Rover (LM) Modes of Operation The air suspension ECU is able to provide four different ride height settings: Off-Road Standard Motorway Access The ride heights are selected via the rotary control switch mounted on the center console. Rotating the switch upwards or downwards selects a different ride height, providing all the outlined required criteria have been met. The center of the rotary switch contains the 'Inhibit/Hold' switch. The 'Inhibit/Hold' switch prevents the air suspension ECU from automatically changing from the currently selected ride height. LED Illumination Next to the rotary control switch are mounted a series of four LED's. An illuminated LED indicates which ride height is active. If a new ride height is selected using the rotary control switch, the 'current' height LED remains illuminated and the 'requested' height LED flashes until the vehicle achieves the new ride height. If a new ride height is selected using the rotary control switch and the 'current' height LED flashes briefly, this indicates that the ride height selection is invalid and will not be performed. When the operating parameters are correct for the new ride height, the height change request must be repeated. Standard Height Standard ride height '740 mm' is used during the majority of driving conditions. This setting is used as a datum point for all the remaining ride heights, and is defined as '0 mm'. All other ride height settings are described as above or below this setting. The standard ride height setting can be active at any vehicle speed. Access or off-road ride height can be selected from the standard ride height using the rotary control or the driver's door module access switch. When the vehicle is in standard ride height, the 'Inhibit/Hold' switch can be selected. The use of this switch prevents automatic height changes from taking place and disables manual height changes until the 'Inhibit/Hold' switch is de-selected. If a height change is selected with the 'Inhibit/Hold' function active, the standard ride height LED will flash. When towing, the electrical connection of the trailer socket will cause the vehicle to set the air suspension to standard ride height. No other ride height setting is available whilst towing. Off-Road Height Off-Road ride height is the highest of the selectable settings, and raises the front of the vehicle by 60 mm and the rear of the vehicle by 50 mm from the standard ride height. Off-Road ride height is selected by turning the rotary control switch upwards when the vehicle is traveling at less than 31 mph (49 km/h). The suspension will return to the standard ride height setting if the rotary switch is turned downwards, or the vehicle speed rises above 31 mph (49 km/h). Technical Training (G538473) 133

135 Range Rover (LM) Lesson 3 Principles of Operation If the vehicle is traveling too fast when Off-Road ride height is selected, the Standard ride height LED will flash, and the request will not be carried out. The driver must repeat the Off-Road ride height request once the vehicle speed has been reduced. When the vehicle is in the Off-Road height setting, the 'Inhibit/Hold' switch will not be operational. Similarly, if the vehicle is in the Standard ride height setting with 'Inhibit/Hold' selected, the vehicle will not move in to the Off-Road height setting until 'Inhibit/Hold' is de-selected. Motor way ride height may be de-selected by the driver at any speed by turning the rotary control switch upwards. The vehicle may return to Motor way ride height if the vehicle speed remains greater than 62 mph (99 km/h) and the driver does not select Inhibit/Hold when the vehicle returns to standard ride height. If the vehicle speed is within the required parameters, the driver can select access ride height by turning the rotary switch downwards or pressing the access switch on the driver's door. Motorway Ride Height Motor way ride height lowers the vehicle by 20 mm from the standard ride height setting (740 mm) and improves the high speed handling of the vehicle. Motor way ride height is only active when the vehicle is traveling at more than 62 mph (99 km/h) for more than 30 seconds. The function is automatic and not selectable by the driver. If the vehicle speed falls below 43 mph (69 km/h) for more than 60 seconds, the ECU automatically returns the vehicle back to the standard ride height setting (740 mm). If the vehicle stops while the Motor way ride height is active, the timer is paused, stopping the vehicle rising un-necessarily. Although Motor way ride height is not selectable by the driver, the Inhibit/Hold switch can be used to keep the Motor way ride height active, thus preventing automatic return to the standard ride height setting. The vehicle will return to the standard ride height setting once the Inhibit/Hold switch is de-selected, and the vehicle speed is below 43 mph (69 km/h). Access Ride Height Access ride height lowers the vehicle by 40 mm from the standard ride height setting when the vehicle is stationary or moving at very low speeds in order to improve access to the vehicle. Access ride height can be selected by operating the access switch either on the driver's door module or the rotary control switch downwards when the vehicle is in standard, off-road or Motor way ride heights. Access Modes Access ride height has three different modes of operation: Access height Access pre-select Crawl mode Access Height If the vehicle is stationary or traveling at less than 15 mph (24 km/h) Access Height mode can be selected. Should the vehicle speed increase to more than 18 mph (29 km/h) the vehicle automatically returns to the standard ride height setting. 134 (G538473) Technical Training

136 Lesson 3 Principles of Operation Range Rover (LM) Access Pre-Select If the vehicle is traveling below 49 mph (78 km/h) and access height is selected, the vehicle enters the 'Access Pre-Select' mode. The ECU acknowledges this request by flashing the 'Access' LED, but the height of the vehicle does not change immediately. If the vehicle is traveling above 49 mph (78 km/h) and access height is selected, the 'Standard' LED will flash and the request will be denied. When access pre-select mode is active, the vehicle will automatically lower to Access ride height if the speed drops below 15 mph (24 km/h) within 65 seconds of the request being made. If the vehicle speed rises to above 49 mph (78 km/h) after 'Access Pre-Select' mode has been selected, or if it takes longer than 65 seconds to come to a rest, access ride height will not be activated and the vehicle will remain at its current height. Crawl Mode Crawl mode does not change the vehicle height, but inhibits all automatic and manual height changes and allows the vehicle to be driven at a higher speed than normal in access mode. If the vehicle is in the Access ride height mode, and the Inhibit/Hold function is selected, 'Crawl' mode is activated. If the vehicle is waiting to initiate the change to Access ride height mode (due to road speed being above the allowed parameter) when the request is made, the pre-selected access request is cancelled and the vehicle returns to standard ride height. The Inhibit/Hold button remains active so that all automatic and manual height changes are disabled. Crawl mode allows the vehicle to be driven at speeds up to 25 mph (40 km/h) without returning to the standard ride height setting. If the vehicle speed reaches 22 mph (35 km/h), a chime will sound from the instrument pack sounder and the message center will display a 'SLOW DOWN' warning message. If the vehicle exceeds 25 mph (40 km/h), crawl mode is cancelled and standard ride height will become active automatically. Inhibit Features A number of conditions exist where a change in ride height would be undesirable. To counter this, the air suspension ECU is programmed with a number of system inhibits. If any of the following conditions exist, the air suspension ECU will suspend height changes and height corrections. Compressor Inhibit A temperature sensor located within the compressor protects the compressor from overheating. If the compressor temperature rises above set limits, the ECU will inhibit compressor operation. The limits are shown in the following table: Technical Training (G538473) 135

137 Range Rover (LM) Lesson 3 Principles of Operation Filling Reservoir Height Regulation Stop Start 100 C (212 F) 80 C (176 F) 110 C (230 F) 105 C (221 F) Compressor Time-Out Compressor operation will be halted after 180 seconds of continuous operation. If the compressor was attempting to regulate system pressure, it remains inhibited for 20 seconds. However, if the compressor was attempting to fill the reservoir, it remains inhibited for 180 seconds. The time-out functions act as a further safe guard against over heating. Cornering If the air suspension ECU registers a cornering force greater than 0.2g it will inhibit all height changes and corrections. The system will remain inhibited until the cornering force falls to less than 0.15g for 0.5 seconds. The air suspension ECU receives a message from the ABS ECU on the CAN bus relating to cornering force. Rapid Acceleration If the air suspension ECU registers rapid acceleration greater than 0.2g it will inhibit all height changes and corrections. The system will remain inhibited until the rapid acceleration falls to less than 0.2g for 1 second. Acceleration is calculated by the air suspension ECU from a vehicle speed signal received via the CAN bus. Rapid Deceleration If the air suspension ECU registers a rapid deceleration greater than -0.2g it will inhibit all height changes and corrections. The system will remain inhibited until the rapid deceleration rises above -0.2g for 1 second. Deceleration is calculated by the air suspension ECU from a vehicle speed signal received via the CAN bus. Axle Articulation To avoid excess pressure differentials between different air springs, the air suspension ECU will inhibit all height changes and corrections if the axle articulation is greater than 350 mm. The system will remain inhibited until axle articulation falls below 350 mm. Vehicle Lift The air suspension ECU will inhibit all height changes and corrections if it detects all four corner heights are greater than 90 mm. This is interpreted as the vehicle being on a wheel free lift with all wheels hanging freely. In this situation, the corner heights will not change when air is released from the air springs. The system will remain inhibited until any of the following conditions exist: 136 (G538473) Technical Training

138 Lesson 3 Principles of Operation Range Rover (LM) All four corners fall below 90 mm The rotary switch is moved to the 'Up' or 'Down' position Vehicle speed rises to greater than 25 mph (40 km/h) for longer than 3 seconds Vehicle Jacking The air suspension ECU will inhibit all height changes and corrections if it detects a corner lowering too slowly for more than 3 seconds. This is interpreted as the corner identified is moving too slowly due to being supported on a car jack. In this situation, the corner height will not change when air is released from the air spring because the car jack acts as a mechanical prop. The system will remain inhibited until any of the following conditions exist: The height of the wheel identified as lowering too slowly, returns to the height where jacking was detected The rotary switch is moved to the 'Up' or 'Down' position Vehicle speed rises to greater than 25 mph (40 km/h) for longer than 3 seconds Maximum Run Time The maximum amount of time the valves within the 5-way valve block can be open is 33% in 300 seconds. Door Open The air suspension ECU will stop all height change requests while any of the doors are open. Vehicle leveling is also inhibited with any door open. Trailer Mode Using the Land Rover electrical trailer kit will cause the air suspension to be set to the standard height setting. If the vehicle is at any other height when the trailer is connected, the air suspension will adjust to the standard height setting and stay in that mode until the trailer is disconnected. System Operation Review Under normal operating conditions, the air suspension ECU will keep the vehicle level at the 'current ride height'. Filters The incoming height sensor signal from the each of the corner height sensors are passed through filters to remove irregular signals produced by road noise or other irregularities. Fast Filter When the vehicle is stationary or a height change is in progress, the signals are passed through a 'fast' filter. The 'fast' filtered signals track the true rate of height change when the vehicle height changes and can also remove road noise when the vehicle is driving. Slow Filter When the vehicle is moving, the signals are passed through a 'slow' filter. The 'slow' filtered signals remove almost all road noise from the signals and outputs a true long term average for each corner height. The 'slow' filtered signals cannot be used to respond to quickly changing ride height changes. Technical Training (G538473) 137

139 Range Rover (LM) Lesson 3 Principles of Operation ECU Monitoring The air suspension ECU monitors each corner height signal using the fast filtered signals if the vehicle is stationary or the slow filtered signals if the vehicle is moving. If the height remains in a 'dead band' which is ±10 mm from the target height, the ECU does not implement any height adjustment changes. When the ECU detects that a corner has moved outside of the 'dead band' the ECU operates the compressor and/or the valves to raise or lower the corresponding corner(s) back into the target height. When the engine is not running, the 'dead band' target height tolerance is increased to ±20 mm. In all cases, the ECU will bring the corner height as close as possible to the target height. The ECU monitors the rate of height change from the corner signals to predict when to close the valve so that the target height does not over shoot. 138 (G538473) Technical Training

140 Lesson 3 Principles of Operation Discovery Series II DISCOVERY SERIES II System Control The leveling system is capable of lowering the rear suspension to within 20 mm of the target height for up to 30 minutes after a door has been opened. This allows the suspension to be leveled as the vehicle is unloaded. With the exception of this unloading function, all other leveling functions are disabled if the doors are open while the vehicle is stationary. The SLABS ECU will disable all leveling activities if the height sensors indicate that the rear suspension is articulated more on one side than the other by more than 100 mm above its target ride height. The SLABS ECU monitors the signals from the height while it is changing the rear ride height. If the rear ride height is not changing as the SLABS ECU expects it to, then all valve and compressor activity will be halted. If the vehicle is moving at a speed greater than 3 mph (5 km/h) when this happens, a fault will be logged in the ECU. Full functionality will be re-enabled when the expected movement is seen, or when the target ride height is changed, e.g. by selection of the off-road mode or by use of the plip function. The SLABS ECU monitors the use of the compressor and the control valves. If these components are being over used then they are disabled to allow them to cool down, and an event code is stored in the ECU for interrogation by T4 diagnostic equipment. Technical Training (G538473) 139

141 Discovery Series II Lesson 3 Principles of Operation If the SLABS ECU decides that the compressor or the valves are being over-used, the leveling behavior of the system may become erratic. Malfunction Lamp The SLS system has two information lamps in the instrument pack. Situated in the bottom left of the instrument pack is the first amber warning lamp. Malfunction Lamp Warning Control The SLABS ECU controls the operation of the SLS audible warning, the SLS warning lamp and the off-road mode warning lamp. When the ignition is switched to position two, the ECU performs a three second bulb check and illuminates the SLS and off-road mode warning lamps in the instrument pack as a bulb operation check. The audible warning is operated by the Body Control Unit (BCU) when it receives a signal from the SLABS ECU. The audible warning is emitted from a speaker in the rear of the instrument pack. If this lamp is continuously illuminated, it indicates that either a malfunction has been detected or that the transit function is set. If the lamp flashes then either the plip function is being used or the transit function is raising the rear suspension. Off-Road Lamp The second amber warning lamp is situated in the top right of the instrument pack. This is the off-road warning lamp. Off-Road Lamp Operational Modes The self leveling suspension has several different modes of operation. These modes of operation are as follows: Extended mode height Off-Road mode Standard ride height Transportation mode Select - Off-Road Mode To provide the vehicle in off-road conditions with additional height, an off-road mode is employed. Activating the off-road mode requires a press of the self leveling switch on the fascia for a minimum of 0.5 second. If the off-road lamp is continuously illuminated, it indicates that the self leveling suspension is in off-road mode. If the off-road lamp flashes, this indicates that the SLS is between the standard ride height and the off-road mode, or that the vehicle is in extended mode. A single audible warning from behind the instrument pack will be given. On release of the switch the off-road warning lamp on the instrument pack will flash, indicating a change of ride height. 140 (G538473) Technical Training

142 Lesson 3 Principles of Operation Discovery Series II When the vehicle is at the off-road target height, the lamp will stop flashing and remain illuminated. Exit - Off-Road Mode To exit the off-road mode, press the self leveling switch for a minimum of 0.5 second. An audible warning from behind the instrument pack will sound once. On release of the fascia switch, the warning lamp will flash and the system returns the rear suspension back to the standard ride height setting. Off-Road Mode Speed Off-Road mode can only be selected if: the vehicle speed is below 19 mph (30 km/h), all doors are closed (if the vehicle is stationary), the engine is running and the rear axle has less than 100 mm of articulation. If any of these conditions are not satisfied, the audible warning will sound three times and the off-road warning lamp will extinguish when the switch is released. Off-Road Heights The off-road height setting is 100 mm from the bump stops on the chassis to the axle. The vehicle will return automatically to the standard setting of 60 mm from the axle bump stops if the vehicle speed exceeds 19 mph (30 km/h). Whilst returning to the standard height setting the warning lamp will be flashing and an audible warning sound will be emitted. Off-Road mode can only be de-selected if all the doors are closed (if the vehicle is stationary) and the rear axle has less than 100 mm of articulation. If any of these conditions are not satisfied, the audible warning will sound three times and the off-road warning lamp will remain illuminated when the switch is released. Extended Mode This mode is not selectable by the driver. Extended mode operates only under the direct control of the SLABS ECU. Extended mode operation will only occur when the SLABS ECU detects the chassis is grounded and the rear wheels are turning with a vehicle speed less than 6 mph (9 km/h). This function is employed to increase the rear suspension height to clear an obstacle. Under extended mode conditions the compressor will operate for 25 seconds. The SLS warning lamp (top right of instrument pack) will flash at a different rate: 75% ON, 25% OFF. This function will be cancelled if the vehicle exceeds speeds of more than 8 mph (13 km/h) or if the fascia switch is pressed for a minimum of 0.5 seconds. Transportation Mode The self leveling suspension has a transportation mode function. This function should be used whenever the vehicle is to be transported on a trailer and is lashed down using the chassis frame. Transportation mode can only be enabled and disabled using T4 diagnostic equipment. The transportation mode function is to lower the rear suspension onto the bump stops, when the engine is not running. Technical Training (G538473) 141

143 Discovery Series II Lesson 3 Principles of Operation In this condition, the malfunction warning lamp (left lower corner of instrument pack) will be illuminated continuously if the ignition is in position two. When the engine is running, the transportation function raises the rear suspension until a gap between the chassis mounted bump stops and axle is 25 mm. In this condition, the malfunction warning lamp (left lower corner of instrument pack) will flash while the suspension is rising, then it will be illuminated continuously when the 25 mm bump stop gap has been achieved. The switch adjusts the headlamp setting to the driver's preference, i.e. if the driver has chosen manually to raise the vehicle into off-road mode, the headlamp aim can be re-adjusted to provide maximum illumination. When the SLABS ECU has leveled the rear suspension, the driver can then set the headlamps to suit the driving requirement. This is especially useful when towing, as the vehicle's pivot point will cause the headlamps to rise at the front due to the weight pulling down on the rear of the vehicle. Headlamp Adjuster Discovery Series II features a headlamp leveling switch located on the vehicle fascia panel. Headlamp Level Switch The remote plip feature is available as an optional accessory. A dedicated air suspension remote transmitter allows the driver to stand outside the vehicle and adjust the height to match that of a trailer hitch for hitching and un-hitching the trailer. Remote Operation This enables the rear vehicle height to be controlled between standard ride height and bump stop height. This option is purchased from the dealer and has to be configured using T4 diagnostic equipment. 142 (G538473) Technical Training

144 Lesson 3 Principles of Operation Discovery Series II RF Receiver The remote transmitter transmits RF signals which are received by the same RF receiver used for the alarm and remote door locking system (located in the headlining rear of sunroof). The RF receiver passes this data as a 25 Hz PWM signal to the BCU (located behind passenger glove box). The BCU then transmits this data to the SLABS ECU to raise or lower the vehicle as required. If point required is overshot then the engine will require running to raise the vehicle up. Remote Preliminary To operate the remote transmitter the ignition must be in position two and all door must be closed. The vehicle must be stationary and the self leveling suspension should be at the standard ride height. Remote Lowering Pressing the lower button on the plip will allow the suspension to be lowered up to 60 mm below the standard ride height setting. Remote Raising Warnings A warning will be issued whilst undertaking the operation of modifying the suspension height in response to the remote transmitter signal. The SLS warning lamp (located top right of instrument pack) will flash and an audible warning sound is emitted. Remote Feature - Exit The rear suspension height will automatically return to the standard ride height setting. This is provided the vehicle speed exceeds 3 mph (5 km/h) for longer than 5 seconds, or instantly if the speed exceeds 7 mph (11 km/h). Door Switches The driver, passenger and rear entry door switches are important in the operation of the self leveling suspension system. The leveling system will not operate if the SLABS ECU detects that the vehicle is stationary and a door is open. Within the SLABS ECU the driver's door switch and the passenger door switches are connected together. Therefore, the SLABS ECU cannot determine which is open, or if more than one door is open. Pressing the raise button on the remote transmitter will allow the vehicle to raise up to the standard ride height setting. Remote Operation If either button on the remote transmitter is released during the remote operation then the suspension height will freeze at whatever height it is currently positioned. Technical Training (G538473) 143

145 Discovery 3 / LR3 Lesson 3 Principles of Operation DISCOVERY 3 / LR3 System Control The driver can manually select, using the air suspension switch, one of four ride states: ON-ROAD - this height is the normal operating height of the vehicle OFF-ROAD - this height is higher than the on-road height and provides improved ground clearance, approach, departure and break over angles ACCESS - this height is lower than the on-road height and makes vehicle entering and exiting easier for the occupants CRAWL (locked at access) - this mode allows the vehicle to be driven at the access height at low speeds to provide increased roof clearance in low car parks, etc TRANSPORTATION - this mode is made available, but it is only selectable or removable using the T4 diagnostic equipment REMOTE - this additional function allows the vehicle to be raised or lowered from outside of the vehicle whilst the vehicle is stationary. This assists with the attachment of a trailer and is achieved using the buttons on the remote handset and the ignition switch in the off position. The remote handset can also be programmed to perform a number of additional functions, however the previous feature will be overwritten EXTENDED - if the air suspension control module senses that the vehicle has grounded and lost traction, the control module can temporarily increase and/or redistribute the volume of air supplied to the affected air spring(s) to maximize the available traction. This 144 (G538473) Technical Training

146 Lesson 3 Principles of Operation Discovery 3 / LR3 is known as extended mode and will be indicated to the driver by the lamps on the air suspension switch flashing. The indicator will change to an amber color and the audible warning will stop when the vehicle speed is reduced. Height Change Restrictions If the air suspension control module senses that the vehicle is prevented from moving upwards or downwards during a height change or leveling correction, the control module will adopt a safe state and further height changes will be suspended. NOTE: Vehicle height changes are prevented if the air suspension control module receives a 'Door Open' signal from the Central Junction Box (CJB). If a fault is detected by the air suspension control module, the control module will reduce the system functionality dependent on the type and severity of the fault. Fault Warnings The control module will also store a fault code which can be retrieved using the T4 diagnostic equipment. If a severe fault occurs, the control module will attempt to put the vehicle in a safe condition. A fault condition is relayed to the driver by the illumination of the air suspension warning indicator, the instrument cluster message center and an audible warning emitted from the instrument cluster. If the detected fault is minor and does not affect vehicle safety, the air suspension warning indicator in the instrument cluster will illuminate in an amber color and the fault should be rectified at the earliest opportunity. If a more severe fault is detected above 31 mph (50 km/h) vehicle speed, the warning indicator will illuminate in a red color and the vehicle should be driven with care until the fault is rectified. On-Road Mode This is the normal ride height for the vehicle. Off-Road Mode Off-road mode will only be activated if the vehicle speed is less than 25 mph (40 km/h). The vehicle will be raised 55 mm (2.2 in) higher than the on-road height to provide additional body clearance and improved approach, departure and break over angles. If the vehicle speed exceeds 31 mph (50 km/h), the air suspension control module will automatically lower the vehicle to the on-road mode height. NOTE: The suspension can be automatically set to off-road mode via Terrain Response and low range programs are selected. At 25 to 28 mph (40 to 45 km/h) a message is displayed to warn the driver to slow down or the vehicle will lower. Access Mode Access mode lowers the vehicle body height by 50 mm (2 in) and provides easier entry, exit and loading of the vehicle. Access mode can be pre-selected when the vehicle is moving. The vehicle will partly lower as the vehicle speed decreases, lowering to the full access mode height when the vehicle reaches 5 mph (8 km/h). An audible warning is emitted by the instrument cluster sounder when the warning indicator is illuminated. Technical Training (G538473) 145

147 Discovery 3 / LR3 Lesson 3 Principles of Operation If the required road speed is not reached within a predetermined time, the air suspension will return the vehicle to the previously selected height. Access mode can be selected at any vehicle speed. Access Mode Speeds When access mode is selected, the response from the air suspension system will depend on the vehicle speed. The following speed ranges indicate the criteria and effects of using the control switch to make a height adjustment. >12.5 MPH (20 KM/H) If the vehicle speed is greater than 12.5 mph (20 km/h) when the access mode switch position is selected, the air suspension control module will wait for up to one minute for the vehicle speed to be reduced The access mode lamp and the lowering lamp will flash while the air suspension control module waits for the vehicle speed to be reduced, the on-road mode lamp will remain illuminated If the vehicle speed is not reduced sufficiently, the access mode request will be cancelled after the one minute time threshold <12.5 MPH (20 KM/H) If the vehicle speed is less than 12.5 mph (20 km/h) when the access mode switch position is selected, the air suspension control module will lower the suspension to a part lowered height and will remain at this height for up to one minute The on-road mode lamp will extinguish as the air suspension control module lowers the suspension to the part lowered height The access mode lamp and the lowering lamp will illuminate When vehicle part lowered is reached, the 'lower' lower lamp will flash If the vehicle speed is not reduced to less than 5 mph (8 km/h) in the one minute period, the access mode request will be cancelled <5 MPH (8 KM/H) If the vehicle speed is less than 5 mph (8 km/h), the suspension will be lowered to access mode immediately The access mode lamp and the lowering lamp will illuminate When the access mode height is reached, the lowering lamp will be extinguished Access height may be selected up to 40 seconds after the ignition is turned off, provided that the driver's door has not been opened within this time. The suspension will automatically rise from access mode when the vehicle speed exceeds 6.2 mph (10 km/h). If access mode was selected directly from off-road mode then the system will return to off-road mode when the vehicle speed exceeds 6.2 mph (10 km/h). Otherwise the system will lift the suspension to On-road height. Off Road - Access Mode Selection When the suspension is in off-road mode height, pressing the air suspension switch once and then a second time before the lowering lamp is extinguished, the control module will lower the suspension to access mode height. The control module will remember to return the suspension to off-road height automatically if the vehicle speed increases above 6.2 mph (10 km/h). 146 (G538473) Technical Training

148 Lesson 3 Principles of Operation Discovery 3 / LR3 Crawl Mode Crawl mode allows the vehicle to driven at a locked access height. This mode can be selected at a speed of less than 21.7 mph (35 km/h) and permits the vehicle to be driven at low speeds to improve clearance in areas with restricted headroom, i.e. car parks. If the vehicle exceeds 24.8 mph (40 km/h), crawl mode will be cancelled and the vehicle will return to on-road height. Selection of crawl mode is via the height selector switch and holding the switch in the down position for longer than 2 seconds. The access mode lamp and the crawl mode lamp will be illuminated. When the control module is in crawl mode, on-road mode height will be selected automatically if the vehicle speed exceeds 25 mph (40 km/h). At 18.6 to 21.7 mph (30 to 35 km/h) a message is displayed in the message center to warn the driver to slow down or the vehicle will raise. Crawl mode can also be manually cancelled by moving the switch in the up direction for 1 second. The access mode lamp and the crawl mode lamp will be extinguished. Automatic Height Changes When the suspension is in off-road mode, access mode or crawl mode height, the air suspension control module will change the suspension height automatically when the vehicle speed exceeds a predetermined threshold. When the suspension is at off-road mode or crawl mode height, the control module issues a warning to advise the driver that the vehicle is approaching the speed threshold. The instrument cluster sounder will emit a chime, a message will be displayed in the message center (if fitted) and the on-road mode lamp and either the raising or lowering lamp will flash. The off-road or crawl mode height speed warning is removed when the vehicle speed is reduced. Door Open Functionality If one or more of the vehicle doors are opened during a height change when the vehicle is stationary, the air suspension control module will restrict any further height changes. The door open signal is transmitted by the CJB on the HS CAN bus and received by the air suspension control module. This keeps the vehicle level to the set height when a door opens to allow for changes in loading conditions. A secondary hardwired door status signal is also transmitted from the CJB to the air suspension control module. This signal provides door status information when the high speed CAN bus is off, i.e. during periodic re-leveling. A hardwired door status signal is also transmitted from the CJB to the air suspension control module. The lamp on the air suspension switch for the target mode height will remain illuminated and the raising or lowering lamp will flash. If all of the doors are closed within 90 seconds, the height change will resume. If the 90 second period is exceeded and all of the doors are not closed, the height change will be cancelled. The mode lamps showing the previously selected height and the target height will be illuminated. Technical Training (G538473) 147

149 Discovery 3 / LR3 Lesson 3 Principles of Operation The mode height change can be re-selected by operating the switch, however, if the vehicle is driven at speed of more than 5 mph (8 km/h) the control module will continue to raise or lower the vehicle to the target mode height. Extended Mode If the vehicle becomes grounded and the traction control becomes operational, the air suspension control module automatically increases the mass of air in the air springs to raise the vehicle clear of the obstruction. Extended mode is activated automatically and cannot be selected manually. When the air suspension control module has activated the extended mode, the off-road mode lamp will flash if the suspension is above off-road mode height. No specific height change figure is provided, this is because the system uses a time basis for extended height changes. When the vehicle becomes grounded the height sensor information is not taken into account, i.e. mistrusted. As the vehicle enters into traction control operation the air suspension system will keep applying more air to the offending corner air spring until traction is regained. To exit the extended mode, press the air suspension switch briefly in the up or down position or drive the vehicle at a speed of more than 12.5 mph (20 km/h). Warning Lamps The off-road mode and on-road mode lamps will flash if the suspension is between off-road mode and on-road mode heights. The on-road mode and access mode lamps will flash if the suspension is between on-road mode and access mode. A message will also be displayed in the message center if fitted. Suspension Prevented From Moving If the air suspension control module is attempting to change the suspension height and it detects that the suspension is prevented from moving, the control module will stop all suspension movement. This can be caused by: Jacking the vehicle Attempting to lower the vehicle onto an object Raising the vehicle against an obstruction The air suspension switch lamps operate as described for extended mode and the same message is displayed in the message center if fitted. To start the air suspension system operating, press the air suspension switch briefly in the up or down position or drive the vehicle at a speed of more than 12.5 mph (20 km/h). Periodic Re-Leveling When the vehicle is parked, the air suspension control module 'wakes up' two hours after the ignition was last switched off and then once every six hours. The vehicle height is checked and if the vehicle is not level within a pre-set tolerance, small downwards height adjustments may be made automatically. Transportation Mode Transportation mode is a factory set mode which locks the suspension to enable the vehicle to be safely lashed to a transporter. This mode can only be selected or deselected using the T4 diagnostic equipment. 148 (G538473) Technical Training

150 Lesson 3 Principles of Operation Discovery 3 / LR3 When the ignition switch is switched off, the vehicle will be lowered onto the bump stops. This ensures that the securing straps do not become loose should there be an air pressure reduction in the air springs. When the engine is running, the air supply unit will operate to raise the vehicle height, allowing the vehicle to be loaded. When the ignition switch is subsequently switched off, the vehicle will again lower onto the bump stops. An audible warning will be emitted from the instrument cluster sounder until the vehicle has reached the higher transportation height. CAN Inputs The air suspension control module uses inputs received on the CAN bus from other systems on the vehicle. The system uses data from the following listed components or systems to control the suspension operation in differing driving conditions. Longitudinal acceleration Lateral acceleration Steering angle Wheel speed data The system will react differently if one or more of these data inputs is missing or incorrect. As an example, if the steering angle sensor is missing or incorrect, the air suspension control module assumes a default value. The default value is defined as zero and may result in some unnecessary leveling activity. Air Supply Unit Relay The air supply unit relay is located in the battery junction box in the engine compartment. The relay is connected directly to the battery via fusible link 10E (60A). The relay coil is connected to and controlled by the air suspension control module. The relay is used by the air suspension control module to control the operation of the compressor. When air supply unit operation is required, the air suspension control module supplies power and ground for the relay coil which energizes, closing the relay contacts. This allows battery voltage via the fusible link to pass through the relay and operate the air supply unit electric motor and the compressor. The battery voltage is also passed from the relay, via a splice joint in the harness, to the air suspension control module and is used as a signal that the air supply unit is receiving power. System Inhibits A number of conditions exist where a change of ride height would be undesirable. To counter this, the air suspension control module is programmed with a number of system inhibits. If any of the conditions detailed below exist, the air suspension control module will suspend height changes and height corrections. Compressor Inhibit The temperature sensors located within the compressor protect the compressor from overheating. If the compressor temperature rises above set limits, the air suspension control module will inhibit the compressor operation. These limits are shown in the following table: Technical Training (G538473) 149

151 Discovery 3 / LR3 Lesson 3 Principles of Operation Compressor Head Temperature Inhibit STOP START LIFTING 150 C (302 F) 130 C (266 F) RESERVOIR FILLING 140 C (284 F) 120 C (248 F) Compressor Brush Temperature Inhibit STOP START LIFTING 140 C (284 F) 120 C (248 F) RESERVOIR FILLING 130 C (266 F) 110 C (230 F) Cornering Inhibit If the air suspension control module registers a cornering force greater than 0.2g it will inhibit all height changes and corrections. The system will remain inhibited until the cornering force falls to less than 0.15g. The air suspension control module receives a message from the lateral acceleration sensor (which is an integral part of the ABS yaw rate sensor) on the high speed CAN bus for the cornering force. Rapid Acceleration Inhibit If the air suspension control module registers a rapid acceleration greater than 0.2g it will inhibit all height changes and corrections. The system will remain inhibited until the rapid acceleration falls to less than 0.15g. Acceleration is calculated by the air suspension control module from a vehicle speed signal received via the high speed CAN bus. Rapid Deceleration Inhibit If the air suspension control module registers a rapid deceleration smaller than -0.2g it will inhibit all height changes and corrections. The system will remain inhibited until the rapid deceleration rises above -0.15g. Deceleration is calculated by the air suspension control module from a vehicle speed signal received via the high speed CAN bus. Vehicle Jacking Inhibit The air suspension control module will inhibit all height changes and corrections if it detects a corner lowering too slowly for more than 1.2 seconds. This is interpreted as the corner identified as moving too slowly being supported on a jack. In this situation, the corner height will not change when air is released from the air spring because the jack acts as a mechanical prop. The system will remain inhibited until any of the following conditions exist: The air suspension switch is moved to the up or down position Vehicle speed rises to more than 9.3 mph (15 km/h) for more than 15 seconds 150 (G538473) Technical Training

152 Lesson 3 Principles of Operation Discovery 3 / LR3 Door Open Inhibit The air suspension control module will stop all height change requests while any of the doors are open. Vehicle leveling will still however continue with a door open. Motorway Lowering This function was not available at launch and has been introduced to the Discovery 3 / LR3 range of vehicles at what is known as Job1 plus 90 days, i.e. available on vehicles 90 days after the launch vehicles were released. This leveling is restricted to keep the vehicle at the height when the door was opened, if the vehicle load changes. Technical Training (G538473) 151

153 Discovery 3 / LR3 Lesson 3 Principles of Operation Pneumatic Schematic Pneumatic Circuit 152 (G538473) Technical Training

154 Lesson 3 Principles of Operation Discovery 3 / LR3 Pneumatic Circuit Item Description Item Description 1. Compressor 14. RH air spring damper module 2. Compressor temperature sensor 15. Cross link valve 3. Air drier unit 16. Rear valve block 4. Reservoir 17. Rear LH corner valve 5. Front LH air spring damper module 18. Rear LH air spring damper module 6. Front valve block 19. Inlet air filter 7. Cross link valve 20. Pilot exhaust valve 8. Front RH air spring damper module 21. Exhaust 9. Front RH corner valve 22. Air silencer 10. Front LH corner valve 23. Pressure relief and exhaust valve 11. Reservoir control valve 24. Motor temperature sensor 12. Pressure sensor 25. Electric motor 13. Rear RH corner valve Spring Pressures Air spring pressure depends on vehicle loading. Nominal Pressure: Fronts 8.5 bar Rears 5.5 bar GVW Pressure: Fronts 9.9 bar Rears 7.8 bar Technical Training (G538473) 153

155 2006MY Range Rover (LM) Lesson 3 Principles of Operation 2006MY Range Rover (LM) System Control The driver can manually select, using the air suspension switch, one of four ride states: ON-ROAD - this height is the normal operating height of the vehicle OFF-ROAD - this height is higher than the on-road height and provides improved ground clearance, approach, departure and break over angles ACCESS - this height is lower than the on-road height and makes entering and exiting the vehicle easier for the occupants CRAWL (Locked at access) - this height allows the vehicle to be driven at the access height at low speeds to provide increased roof clearance in low car parks etc. HIGH SPEED - A non-selectable, automatic high speed mode is provided which lowers the vehicle height to improve vehicle handling. NOTE: Vehicle height changes are restricted if the air suspension control module receives a 'Door Open' signal from the Generic Electronic Module (GEM) and the speed is less than 5 mph (8 km/h). An additional 'TRANSPORTATION' mode is also available but is only selectable using T4. When this mode is active most vehicle systems, in addition to the air suspension, are inhibited or restricted to a minimal functionality. If the air suspension control module senses that the vehicle has grounded and lost traction, the control module can temporarily increase and/or redistribute the volume of air supplied to the affected air spring(s) to 154 (G538473) Technical Training

156 Lesson 3 Principles of Operation 2006MY Range Rover (LM) maximize the available traction. This is known as extended mode and will be indicated to the driver by the lamps on the air suspension switch flashing. If the air suspension control module senses that the vehicle is prevented from moving upwards or downwards during a height change or leveling correction, the control module will adopt a safe state and further height changes will be suspended. If a fault is detected by the air suspension control module, the control module will reduce the system functionality dependent on the type and severity of the fault. The control module will also store a fault code which can be retrieved using T4. If a severe fault occurs, the control module will attempt to put the vehicle in a safe condition. A fault is relayed to the driver by the instrument cluster message center and an audible warning emitted from the instrument cluster. If the detected fault is minor and does not affect vehicle safety, the instrument cluster message center will display the message 'SUSPENSION FAULT' and a chime will be emitted. The fault should be investigated and rectified as soon as possible. If the detected fault is more serious, the message center will display the message 'SUSPENSION FAULT NORMAL HEIGHT ONLY' and a chime will be emitted. The fault should be investigated and rectified as soon as possible. If the detected fault is more severe the message center will display the message 'SUSPENSION FAULT MAX SPEED 50KPH' and two chimes will be emitted every thirty seconds if this speed is exceeded. The message will change to 'SUSPENSION FAULT' when the vehicle speed is reduced to less than 31 mph (50 km/h). The vehicle should be driven slowly until the fault is rectified. Technical Training (G538473) 155

157 2006MY Range Rover (LM) Lesson 3 Principles of Operation Air Suspension Control Switch Item Description Off-Road height LED On-Road (normal) height LED Height change LED Access height LED 156 (G538473) Technical Training

158 Lesson 3 Principles of Operation 2006MY Range Rover (LM) Item Description , Air suspension rotary control switch Hold button and LED Drivers door module access switch System Operation Under normal operating conditions, the air suspension control module keeps the vehicle level at the 'current' ride height. The incoming height signals from the sensors are passed through filters to remove irregular signals produced by road noise or other irregularities. When the vehicle is stationary or a height change is in progress, the signals are passed through a 'fast' filter, which tracks the true rate of change of height. When the vehicle is moving, the signals are passed through a 'slow' filter. The 'slow' filtered signals remove almost all road noise from the signals and output a true long term average for each corner height. The 'slow' filtered signals cannot be used to respond quickly during height changes. Software Filters The air suspension control module monitors each corner height signal using the fast filtered signals if the vehicle is stationary or the slow filtered signals if the vehicle is moving. If the height remains in a 'dead band' which is ±10 mm from the target height, the control module does not implement any height adjustment changes. When the control module detects that a corner has moved outside of the 'dead band', the control module operates the compressor and/or the valves to raise or lower the corresponding corner(s) back into the target height. Modes of Operation On-Road Mode This is the normal ride height for the vehicle. Off-Road Mode Off-road mode will only be selectable if the vehicle speed is less than 25 mph (40 km/h). The vehicle will be raised 55 mm (2.2 in) higher than the on-road mode to provide additional body clearance and improved approach, departure and break over angles. If the vehicle speed exceeds 31 mph (50 km/h), the air suspension control module will automatically lower the vehicle to the on-road mode height. At 25 to 28 mph (40 to 45 km/h) a message is displayed in the message center to warn the driver to slow down or the vehicle will lower. Access Mode Access mode lowers the vehicle body height by 40 mm (1.6 in) and provides easier entry, exit and loading of the vehicle. Access mode can be pre-selected when the vehicle is moving. The vehicle will partly lower as the vehicle speed decreases, lowering to the full access mode height when the vehicle reaches 5 mph (8 km/h). Technical Training (G538473) 157

159 2006MY Range Rover (LM) Lesson 3 Principles of Operation If the required road speed is not reached within a predetermined time, the air suspension will return the vehicle to the previously selected height. Access mode can be selected at any vehicle speed. When access mode is selected, the response of the air suspension system will depend on the vehicle speed: >12.5 mph (20 km/h If the vehicle speed is more than 12.5 mph (20 km/h), the air suspension control module will wait for up to one minute for the vehicle speed to be reduced. The access mode LED and the height change LED will flash while the air suspension control module waits for the vehicle speed to be reduced, the on-road mode lamp will remain illuminated. If the vehicle speed is not reduced sufficiently, the access mode request will be cancelled after 1 minute. <12.5 mph (20 km/h) If the vehicle speed is less than 12.5 mph (20 km/h), the air suspension control module will lower the suspension to a part lowered height and will remain at this height for up to one minute. The on-road mode lamp will extinguish as the air suspension control module lowers the suspension to the part lowered height. The access mode lamp and the height change LED will illuminate. When part lowered is reached, the height change LED will flash. If the vehicle speed is not reduced to less than 5 mph (8 km/h) in the one minute period, the access mode request will be cancelled. <5 mph (8 km/h) If the vehicle speed is less than 5 mph (8 km/h), the suspension will be lowered to access mode immediately. The access mode LED and the height change LED will illuminate. When the access mode height is reached, the height change LED will be extinguished. Access height may be selected up to 40 seconds after the ignition is turned off, provided that the driver's door has not been opened within this time. The vehicle will automatically rise from access mode when the vehicle speed exceeds 6.2 mph (10 km/h). If access mode was selected directly from off-road mode then the system will return to off-road mode when the vehicle speed exceeds 6.2 mph (10 km/h). Otherwise the system will lift the suspension to on-road height. Selecting Access Mode Directly from Off-Road Mode When the suspension is in off-road mode height, pressing the air suspension rotary switch once and then a second time in a downward direction before the height change LED is extinguished, the control module will lower the suspension to access mode height. The control module will remember to return the suspension to off-road height automatically if the vehicle speed increases above 6.2 mph (10 km/h). Alternatively, pressing the driver's door module access switch once will perform the same function. Crawl (Locked at Access) Mode Crawl mode allows the vehicle to be driven at access height. The vehicle is locked in access height and can be selected at a speed of less than 21.7 mph (35 km/h) and can be driven at low speeds to improve clearance in areas with restricted headroom, i.e. car parks. If the vehicle exceeds 25 mph (40 km/h), crawl mode will be cancelled and the vehicle will return to on-road height. To select crawl mode the vehicle must first be in access mode. 158 (G538473) Technical Training

160 Lesson 3 Principles of Operation 2006MY Range Rover (LM) Crawl mode is selected by pressing the 'hold' button once. When selected, the hold button LED will be illuminated. When the control module is in crawl mode, on-road mode height will be selected automatically if the vehicle speed exceeds 25 mph (40 km/h). At 18.6 to 21.7 mph (30 to 35 km/h) a message is displayed in the message center to warn the driver to slow down or the vehicle will raise. Crawl mode can also be manually cancelled by pressing the hold button once. The access mode LED and the hold LED will be extinguished. High Speed Mode High speed mode is a non-selectable, automatic mode which lowers the vehicle height by 20mm to improve vehicle handling. This feature is fully automated and is 'invisible' to the driver. If the vehicle speed exceeds 100 mph (160 km/h) for more than five seconds, the air suspension control module initiates the high speed mode. When the vehicle speed reduces to less than 80 mph (130 km/h) for more than 30 seconds, the vehicle returns to the on-road height. This function is cancelled if a trailer is connected to the trailer socket. Automatic Height Change Warnings When the suspension is in off-road mode, access mode or crawl mode height, the air suspension control module will change the suspension height automatically when the vehicle speed exceeds a predetermined threshold. When the suspension is at off-road mode or crawl mode height, the control module issues a warning to advise the driver that the vehicle is approaching the speed threshold. The instrument cluster sounder will emit a chime, a message will be displayed in the message center and the on-road mode LED and the height change LED will flash. The off-road mode or crawl mode height speed warning is removed when the vehicle speed is reduced. Special Modes Door Open Functionality If one or more of the vehicle doors are opened during a height change when the vehicle is stationary, the air suspension control module will restrict further height change. The door open signal is transmitted by the generic electronic module (GEM) on the 'K' bus to the instrument cluster gateway and from the cluster it is transmitted on the high speed CAN bus and received by the air suspension control module. This keeps the vehicle level to the set height when a door opens to allow for changes in loading conditions. The LED on the air suspension LED display for the target mode height will remain illuminated and the height change LED will flash. If all of the doors are closed within 90 seconds, the height change will resume. If the 90 second period is exceeded and all of the doors are not closed, the height change will be cancelled. The mode LEDs showing the previously selected height and the target height will be illuminated. Technical Training (G538473) 159

161 2006MY Range Rover (LM) Lesson 3 Principles of Operation The mode height change can be re-selected by operating the rotary switch, however, if the vehicle is driven at speed of more than 5 mph (8 km/h) the control module will continue to raise or lower the vehicle to the target mode height. Extended Mode If the air suspension control module senses, via the height sensors, that the vehicle has become grounded, the air suspension control module automatically increases the mass of air in the air springs to raise the vehicle clear of the obstruction. Extended mode is activated automatically and cannot be selected manually. When the air suspension control module has activated the extended mode, the off-road mode lamp will flash if the suspension is above off-road mode height. The off-road mode and on-road mode lamps will flash if the suspension is between off-road mode and on-road mode heights. The on-road mode and access mode lamps will flash if the suspension is between on-road mode and access mode. A message will also be displayed in the message center. To exit the extended mode, press the air suspension switch briefly in the up or down position or alternatively drive the vehicle at a speed of more than 12.5 mph (20 km/h). Additional Lift in Extended Mode When extended mode has been invoked and the automatic lifting of the vehicle is complete, the driver can request an additional lift of the vehicle. This can be particularly useful when extended mode has been activated on soft surfaces. The additional lift can be requested once the height change LED has extinguished. Press and hold the air suspension switch in the up position for 3 seconds whilst simultaneously depressing the brake pedal. A chime from the instrument cluster will sound to confirm that the request has been accepted. The height change LED will be illuminated while the vehicle is being lifted. Suspension Prevented From Moving If the air suspension control module is attempting to change the suspension height and it detects that the suspension is prevented from moving, the control module will stop all suspension movement. This can be caused by jacking the vehicle, attempting to lower the vehicle onto an object or raising the vehicle against an obstruction. The air suspension switch lamps operate as described for extended mode and the same message is displayed in the message center. To re-start the air suspension system operating, press the air suspension switch briefly in the up or down position or drive the vehicle at a speed of more than 12.5 mph (20 km/h). Periodic Re-leveling When the vehicle is parked, the air suspension control module 'wakes up' two hours after the ignition was last switched off and then once every six hours. The vehicle height is checked and if the vehicle is not level within a pre-set tolerance, small downwards height adjustments may be made automatically. 160 (G538473) Technical Training

162 Lesson 3 Principles of Operation 2006MY Range Rover (LM) Transportation Mode Transportation mode is a factory set mode which locks the suspension to enable the vehicle to be safely lashed to a transporter. The suspension transportation mode is automatically set when the vehicle is configured for transportation mode using T4. Transportation mode also affects other vehicle systems which are inhibited or restricted to minimal functionality. When the ignition switch is switched off, the vehicle will be lowered onto the bump stops. This ensures that the securing straps do not become loose should air leak from the air springs. When transportation mode is active, the off-road, access and hold switches are disabled. Periodic re-leveling is also disabled. When the engine is started, the air suspension control module will cause the vehicle to rise to a height of 20mm to allow sufficient ground clearance for the vehicle to be loaded. While the height is changing, all the LEDs in the air suspension control switch will flash and a chime will be emitted by the instrument cluster. When the height of 20mm is reached, all the LEDs will illuminate continuously and the chime will stop. When the engine is switched off, the air suspension control module will cause the vehicle to lower to a height of 60mm to allow the vehicle to be strapped down. While the height is changing, all the LEDs in the air suspension control switch will flash and a chime will be emitted by the instrument cluster. When the height of 60mm is reached, all the LEDs will illuminate continuously and the chime will stop. Calibration Mode This mode is used when the air suspension control module has been replaced or a height sensor or suspension component has been dismantled or replaced. The following conditions apply when the vehicle is in calibration mode: Calibration Conditions The ride height is set to tight tolerance Fault reaction to Vehicle Identification Number (VIN) mis-match with the Car Configuration File (CCF) is disabled The raise, lower, access and hold switches are disabled System is controlled to on-road height only. System Inhibits A number of conditions exist where a change in ride height is undesirable. To counter this, the air suspension control module is programmed with a number of system inhibits. If any of the conditions detailed below exist, the air suspension control module will suspend height changes and height corrections. Compressor Time-Out Two temperature sensors are located within the compressor to prevent overheating. If the temperature of the motor brush assembly or the compressor cylinder head rise above pre-set limits, the air suspension control module will inhibit the compressor operation. The limits are detailed in tables in the Air Supply Unit section of this workbook. Technical Training (G538473) 161

163 2006MY Range Rover (LM) Lesson 3 Principles of Operation Cornering If the air suspension control module registers a cornering force greater than 0.2g it will inhibit all height changes and corrections. The system will remain inhibited until the cornering force falls to less than 0.15g. The air suspension control module receives a message from the lateral acceleration sensor (which is an integral part of the ABS yaw rate sensor) on the high speed CAN Bus for the cornering force. Rapid Acceleration If the air suspension control module registers a rapid acceleration greater than 0.2g it will inhibit all height changes and corrections. The system will remain inhibited until the rapid acceleration falls to less than 0.15g. Acceleration is calculated by the control module from a vehicle speed signal received via the high speed CAN bus. Rapid Deceleration If the air suspension control module registers a rapid deceleration smaller than - 0.2g it will inhibit all height changes and corrections. The system will remain inhibited until the rapid deceleration rises above g. Deceleration is calculated by the control module from a vehicle speed signal received via the high speed CAN bus. Vehicle Jacking The air suspension control module will inhibit all height changes and corrections if it detects a corner lowering too slowly for more than 1.2 seconds. This is interpreted as the corner identified as moving too slowly being supported on a jack. In this situation, the corner height will not change when air is released from the air spring because the jack acts as a mechanical prop. The system will remain inhibited until any of the following conditions exist: The air suspension rotary switch is moved to the up or down position The vehicle speed rises to more than 9.3 mph (15 km/h) for more than 15 seconds. Door Open The air suspension control module will stop all height change requests while any of the doors are open. Vehicle leveling continues with a door open by keeping the vehicle at the height when the door was opened if the vehicle load changes. RIDE HEIGHT CONTROL Height Control The air suspension control module is able to provide three different ride heights: On-road (normal) Off-road Access. The ride heights are selected via the rotary control switch mounted on the center console. Rotating the switch upwards or downwards selects a different ride height (providing all the criteria outlined below are met). The center of the rotary switch contains the 'Hold' switch. The 'Hold' switch allows the air suspension control module to lock the access mode in crawl mode. 162 (G538473) Technical Training

164 Lesson 3 Principles of Operation 2006MY Range Rover (LM) The rotary control switch contains one LED for the 'Hold' function. Four further LEDs are located in a display panel adjacent to the switch and display height change, off-road mode, on-road (normal) mode and off-road mode. The symbols illuminate to show the current selected ride height and if a height change is in progress. If a requested height change is not allowed, i.e. vehicle speed too fast, the height change LED will flash and a chime will be emitted. A flashing off-road or access LED indicates that the air suspension system is in a waiting state or the system will override the driver's selection because the speed threshold is too high. The driver can also ignore the system's warning signals and allow the height to change automatically. for example, increasing the vehicle speed to more than 25 mph (40 km/h) will cause the control module to automatically change the ride height from off-road to on-road mode. On-Road On-road ride (normal) height is used during most driving conditions. This setting is used as a datum for the remaining ride heights and is defined as 0 mm. All other ride height settings are described as above or below this setting. The on-road height can be active at any vehicle speed. Access or off-road ride height can be selected from on-road ride height using the rotary control or the drivers door access switch. Off-Road Off-road mode will only be selectable if the vehicle speed is less than 25 mph (40 km/h). The vehicle will be raised 55 mm (2.2 in) higher than the on-road (normal) mode to provide additional body clearance and improved approach, departure and break over angles. If the vehicle speed exceeds 31 mph (50 km/h), the air suspension control module will automatically lower the vehicle to the on-road mode height. At mph (40-45 km/h) a message is displayed in the message center to warn the driver to slow down or the vehicle will lower. High Speed High speed height lowers the vehicle by 20 mm, and improves the high speed handling of the vehicle. High speed height is only active when the vehicle is traveling at more than 100 mph (160 km/h) for more than 5 seconds, and is not selectable by the driver. If the vehicle speed falls to below 80 mph (130 km/h) for more than 30 seconds, the control module automatically returns the vehicle to the on-road height setting. If the vehicle stops while the high speed height is active, the timer is paused, stopping the vehicle rising unnecessarily. When towing, the electrical connection of the Land Rover trailer socket will be detected and stop automatic lowering to the 20mm position. Access Height Access ride Height lowers the vehicle by 40 mm (1.6 in) when the vehicle is stationary or moving at very low speeds in order to improve ease of access to the vehicle. Access ride Height can be selected by operating the access switch on the drivers door module when the vehicle is in on-road Height or by turning the rotary Technical Training (G538473) 163

165 2006MY Range Rover (LM) Lesson 3 Principles of Operation control switch downwards once when the vehicle is in on-road Height or twice when the vehicle is in off-road Height. Access Height can be selected at any vehicle speed. When access Height is selected, the response of the air suspension system will depend on the vehicle speed. Access ride Height has three different modes of operation: Access Height Access Select from Off-Road Height Crawl Mode. Access Height If the vehicle speed is 5 mph (8 km/h) or less, the vehicle will lower to full access Height immediately. The access Height LED and the Height change LED will illuminate. When the access Height is reached, the Height change LED will extinguish. If the vehicle is traveling at less than 12.5 mph (20 km/h) 'Access Height' mode can be selected. The control module will lower the suspension to a part lowered Height and will remain at this Height for up to one minute for the vehicle speed to be further reduced. The on-road LED will be extinguished as the control module lowers the suspension to the part lowered Height. The access Height LED and the Height change LED will both be illuminated. When the part lowered Height is reached, the Height change LED will flash. If the vehicle speed is not reduced to less than 5 mph (8 km/h) within the one minute period, the access Height request will be cancelled and the vehicle will return to on-road Height. If the vehicle speed is more than 12 mph (20 km/h), the control module will wait for up to one minute for the vehicle speed to be reduced. The access Height LED and the Height change LED will flash while the control module waits for the vehicle speed to be reduced, the on-road Height LED will remain illuminated. If the vehicle speed is not reduced sufficiently, the access Height request will be cancelled after one minute. Access Height may be selected up to 40 seconds after the ignition is switched off, provided that the driver's door has not been opened within this time. The suspension will automatically rise from access Height when the vehicle speed exceeds 6.2 mph (10 km/h). If access Height was selected directly from off-road mode, then the system will return to off-road Height when the vehicle speed exceeds 6.2 mph (10 km/h). Otherwise the system will return the suspension to on-road Height. Access Selected from Off-Road Height When the suspension is in off-road ride Height, rotating the air suspension rotary switch downwards once and then a second time before the Height change LED has extinguished, or pressing the access switch on the driver's door module once, will cause the control module to lower the suspension to access Height (providing the speed thresholds are met). The control module will remember to return the suspension to off-road Height automatically if the vehicle speed increases to more than 6.2 mph (10 km/h). Crawl Mode (Locked at Access Height) Crawl mode does not change the vehicle Height, but modifies automatic Height changes and allows the vehicle to be driven at access Height but at a higher speed than in access mode. Crawl mode is selected when the vehicle is at the access ride Height and 'Hold' is selected. 164 (G538473) Technical Training

166 Lesson 3 Principles of Operation 2006MY Range Rover (LM) If 'Access Height' has been selected, but the air suspension control module has not lowered the vehicle because the road speed is too high, when 'hold' is selected the 'Access Height' request is cancelled and the vehicle remains at on-road ride Height. The 'Hold' button remains active so that all automatic and manual Height changes are disabled. Crawl mode allows the vehicle to be driven at speeds up to 25 mph (40 km/h) without returning to the on-road Height. If the vehicle speed reaches 22 mph (35 km/h), a chime will sound from the instrument cluster sounder and the message center will display a 'SLOW DOWN' warning message. If the vehicle speed exceeds 25 mph (40 km/h), crawl mode is cancelled and on-road Height will become active automatically. Technical Training (G538473) 165

167 Notes

168 Lesson 4 Diagnostics Objectives On completing this lesson, you will be able to: Follow the recommended route for diagnostics. Use the chart to process further diagnosis by eliminating certain scenarios or components. Technical Training (G538476) 167

169 Range Rover (LP) Lesson 4 Diagnostics RANGE ROVER (LP) System Checks Preliminary Checks This section covers possible air suspension component faults. However a preliminary visual check of the components within the system plus any relevant fuses and relays should be carried out prior to undertaking any detailed fault diagnosis procedures. Full diagnostics are covered by the T4 diagnostic equipment. Hard Ride Possible Cause Loss of air pressure in the system resulting in the chassis bump stops resting on the front and rear axles Incorrect ride height Remedy Check air system components for faults and air suspension harness for leaks Re-calibrate the air suspension system. Refer to T4 diagnostic equipment 168 (G538475) Technical Training

170 Lesson 4 Diagnostics Range Rover (LP) Permanent Standard Ride Height Possible Cause Height sensor(s) inoperative due to loose or disconnected multi-plug Height sensor linkage disconnected or damaged Faulty height sensor(s) Leaking air supply to air spring(s) Faulty or leaking air spring diaphragm Faulty pressure switch Remedy Reconnect multi-plug Reconnect or renew height sensor linkage Renew height sensor(s) Check air harness connections and pipes for damage or scoring Renew air spring assembly Refer to T4 diagnostic equipment Air Suspension System Faulty or Inoperative Possible Cause Blown air suspension system fuse Blown fuse covering Height Control or Inhibit Switch Faulty 'Height Control' switch resulting in the vehicle height remaining at last height setting until the engine is switched off Faulty 'Inhibit' switch leading to vehicle not operating automatically between standard and low modes Compressor inoperative resulting in no air pressure due to loose or disconnected multi-plug Blown compressor maxi fuse Faulty compressor relay leading to the compressor running continuously Loss of air pressure in the air pressure system Faulty delay relay If the delay relay fails with a short circuit the system will be powered constantly resulting in a flat battery Remedy Check for cause and renew Fuse 44 Check for cause and renew Fuse 17 Refer to T4 diagnostic equipment to confirm the fault and renew 'Height Control' switch Refer to T4 diagnostic equipment to confirm the fault and renew 'Inhibit' switch Check and reconnect compressor multi-plug Check for cause and renew maxi Fuse 2 Renew relay RL20 Check the air system components for faults and air harness for leaks Renew relay AMR3284 Technical Training (G538475) 169

171 Range Rover (LP) Lesson 4 Diagnostics Excessive Front End Body Roll Possible Cause Deflated air spring Faulty valve block Remedy Check air system components for faults and air harness for leaks. Rectify or renew components where necessary Refer to T4 diagnostic equipment Vehicle Leaning and Air Suspension Inoperative Possible Cause Faulty height sensor Incorrect height sensor calibration Remedy Refer to T4 diagnostic equipment to locate faulty height sensor. Renew height sensor and re-calibrate air suspension system Re-calibrate the air suspension system Message center Warnings - Requiring Driver Response Message EAS MANUAL SLOW 20 MPH MAX EAS FAULT SLOW 35 MPH MAX Meaning Vehicle locked in Access Road speed is too high for current ride height There is a fault with the air suspension Air suspension fault Solution EAS warning! The vehicle is being driven on its bump stops Slow down to less than 20 mph Consult your Land Rover dealer Slow to 35 mph and seek qualified assistance 170 (G538475) Technical Training

172 Lesson 4 Diagnostics Range Rover (LM) RANGE ROVER (LM) System Checks The air suspension system calibration must be carried out after the following components have been replaced: Air suspension ECU Height sensors Body panel incorporating suspension fixing points To calibrate the air suspension system connect the T4 diagnostic equipment and follow the on-screen instructions. Calibration Notes: The vehicle can be calibrated laden or un-laden, but Gross Vehicle Weight (GVW) must not be exceeded. Tires must be all the same size and at the correct tire pressures. Ensure the floor used as the calibration area is level and smooth in all directions to enable calibration to be carried out successfully. Diagnostics The air suspension ECU can store fault codes which can be retrieved using the T4 diagnostic equipment. The diagnostic information obtained through the diagnostic socket which is located in the fascia, in the driver's stowage tray. The fascia secured socket is protected by a hinged cover. The diagnostic socket allows the exchange of information between the various ECU's on the various bus systems and the T4 diagnostic equipment or a diagnostic tool. Technical Training (G538475) 171

173 Range Rover (LM) Lesson 4 Diagnostics This allows fast retrieval of diagnostic information and programming of certain functions using the T4 diagnostic equipment or suitable diagnostic tool. Fault Detection The air suspension ECU performs fault detection and plausibility checks. Fault detection is limited to faults that the ECU can directly measure. These faults are as follows: Sensor hardware faults Valve hardware faults Sensor faults Actuator faults Bus failure ECU hardware errors Plausibility Checks Plausibility checks are checks on signal behavior. These are as follows: Average height does not change correctly: Height changes slowly Suspension moves in the wrong direction Reservoir pressure: Does not increase when reservoir filling requested Does not decrease when reservoir used to lift vehicle Does not decrease when reservoir is vented Pressure varies too much when inactive Compressor temperature: Increases when compressor inactive Does not increase when compressor active 'Energy' used to change height of corner: Too much energy used Height change takes too long Long term filtered height does not reach target Sensor activity: Signal floating Inconsistent signal characteristic (signal on one axle is varying but the other side remains static Constant articulation when moving Ride Quality When a fault is detected, the ECU will attempt to maintain a comfortable ride quality whilst maintaining a restricted functionality of the air suspension system. System Functionality The system functionality when a fault exists depends on the severity of the detected fault. Faults are defined as minor or major. Minor faults: Most sensor faults (hardware or plausible faults) Cross link valve failure Reservoir valve failure For most minor faults, height changes are inhibited except for a return to the standard height setting. If the air suspension system is not in standard height mode, the air suspension ECU will respond with a request for a manual or automatic height change to return the vehicle to the standard ride height setting. The air suspension ECU will continue to level the vehicle at the current ride height. Major faults: Compressor faults Plausibility errors, for example: 172 (G538475) Technical Training

174 Lesson 4 Diagnostics Range Rover (LM) Average height does not increase when lifting and vehicle is moving. This could be caused by a compressor fault or fault in the reservoir valve. Reservoir pressure decreases when filling requested. This could be caused by a leak in the common gallery of the valve block or connecting air harness pipework. For major system faults, the air suspension ECU will not level the vehicle at the current ride height. The air suspension ECU freezes all height changes until it receives a manual or automatic request for height change. The ECU will return to standard height and freezes once standard height is achieved. Speed Signal Loss If the air suspension ECU loses information regarding vehicle speed, the ECU cannot determine if the current ride height is suitable for the vehicle speed. The ECU immediately returns to a 'Default Height', which is 20 mm below stand ride height (Motor way ride height). Once at the default height setting, the air suspension ECU will continue to level the vehicle at this height setting. The loss of speed signal could be due to a fault in the CAN bus network or the ABS ECU. A speed signal fault is unlikely to be a fault in the air suspension ECU. This fault could be caused for example, by disconnecting the battery and not re-calibrating the steering sensor immediately upon battery re-connection. In this case a CAN bus fault is recorded in the error memory. When the fault is repaired, the air suspension ECU will resume full functionality, but the CAN error remains in memory. ECU Hardware Fault If the suspension is above standard ride height and the ECU cannot lower the suspension or cannot determine the vehicle height, all height changes will be frozen. The ECU will issue a message on the CAN bus which is received by the instrument pack, which displays a maximum advisable speed in the message center of '35MPH'. An immediate freeze of the vehicle height is caused by the following: Failure of more than one height sensor Implausible articulation detected Valve or solenoid failure (does not include reservoir valve) Stuck corner or whole vehicle diagnosed used plausibility of sensor inputs If the air suspension ECU has a hardware fault, the ECU will disable all air suspension functions. Detectable hardware errors include memory error, ECU failure or calibration errors. Fault Messages The air suspension has two methods which it can use to inform the driver of a fault in the air suspension system. The methods used are as follows: Instrument pack message center Rotary control switch LED's If this fault is seen, other ECU's using the CAN bus should also be checked for fault codes. Technical Training (G538475) 173

175 Range Rover (LM) Lesson 4 Diagnostics LED's When minor faults occur and the air suspension ECU is able to level the vehicle to the 'current ride height', the rotary control switch LED's will display the current ride height. When the vehicle returns to the standard ride height all further height changes are disabled, the 'Hold LED' in the rotary control switch will be permanently illuminated. Messages If a fault occurs and the ECU can determine the ride height and the vehicle is not above the standard ride height setting, the driver will be notified by an 'AIR SUSP. INACTIVE' message in the message center. If the air suspension ECU cannot determine the ride height of the vehicle the 'AIR SUSP. INACTIVE' message is accompanied with an alternating 'MAX 35MPH' message. If the air suspension ECU suffers a major failure and there is no air suspension control, all the rotary control switch LED's will remain unlit. 174 (G538475) Technical Training

176 Lesson 4 Diagnostics Range Rover (LM) Bus Network Bus Network Connection Bus Network Connection Connection Type: A = Hardware B = 'K' Bus C = Diagnostic bus D = CAN bus Technical Training (G538475) 175

177 Range Rover (LM) Lesson 4 Diagnostics Item Description Item Description 1. Fuse 15A - Permanent supply 13. Reservoir pressure sensor 2. Fusible link 100A 14. Valve block 3. Fuse 50A 15. Front cross link valve 4. Air suspension relay 16. Rear cross link valve 5. Compressor and motor 17. LHR height sensor 6. Temperature sensor 18. RHR height sensor 7. HP exhaust valve 19. LHF height sensor 8. Exhaust valve 20. RHF height sensor 9. Control switch 21. ABS ECU 10. Body Control Unit (BCU) 22. Instrument cluster 11. Air suspension ECU 23. Diagnostic socket 12. Driver door module (access mode switch) 176 (G538475) Technical Training

178 Lesson 4 Diagnostics Range Rover (LM) Pneumatic Circuit Technical Training (G538475) 177

179 Range Rover (LM) Lesson 4 Diagnostics Pneumatic Circuit Item Description Item Description 1. LHF damper /air spring 12. Compressor inlet /exhaust valve 2. Front cross link valve 13. HP exhaust valve 3. RHF damper /air spring 14. Exhaust pilot valve 4. LHF corner valve 15. Pressure limiting valve 5. Reservoir valve 16. Electric motor 6. RHF corner valve 17. Pressure relief valve 7. RHR corner valve 18. Restriction 8. LHR corner valve 19. Drier unit 9. RHR air spring 20. Compressor 10. Rear cross link valve 21. Reservoir 11. LHR air spring 22. Pressure sensor 2. T4 Fault Code 53 (ECU Fault) ECU Diagnosis On a number of occaisions it has been found that the Air Suspension ECU is being change when no fault exists with the ECU. The ECU stores fault codes for numerous air suspension system component failures. In the majority of cases, changing the ECU will re-activate the system and may appear to have rectified the fault, but it will not solve the root cause of the problem. Therefore an Air Suspension ECU Diagnosis procedure has been implemented to prevent this occurence from being repeated. ECU Fault Reasons There are only four reasons for changing the Air Suspension ECU: 1. T4 Fault Code 52 (ECU Memory Fault) 3. T4 Fault Code 55 (ECU Calibration Fault) 4. Communications to the EAS ECU have failed. Bulletin LM Bulletin LM details the way that these four Fault Codes should be diagnosed before replacing an ECU. All other problems that appear to be ECU related are due to other components and/or wiring/air harness faults. Normal fault diagnosis should be used for component and harness faults. The solving of height sensor problems should always be accompanied by re-calibrating the vehicle trim heights. Should a customer express concern regarding air suspension, refer to the Diagnostic Procedure detailed in the bulletin for correct system diagnosis before changing the ECU. 178 (G538475) Technical Training

180 Lesson 4 Diagnostics Discovery Series II Discovery Series II System Checks Failures are indicated by the SLS warning lamp in the bottom left corner of the instrument pack illuminating continuously in an amber color. The SLABS ECU can be interrogated via T4 diagnostic equipment to: Diagnose faults stored in the ECU memory, current or historic Test individual parts of the system Initialize a SLABS ECU for operation and configuration of functionality T4 diagnostic equipment will also be required to calibrate the settings of new height sensors and configure the remote transmitter (if applicable). The following tables show the type of system failures and their effects on the system operation. Height Sensors Failure Effect Sensor output stuck at 5v Sensor output stuck at 0v Mechanical link between radius arm and sensor broken Vehicle will not level Vehicle will not level Vehicle will not level Technical Training (G538475) 179

181 Discovery Series II Lesson 4 Diagnostics Door Switch Inputs Failure Harness leads for open doors are broken or shorted to VBatt Harness leads to door(s) shorted to earth Effect Air suspension levels when one or more doors are open Air suspension will not level SLS off-road mode switch Failure Effect Fault in wiring harness Failure of off-road mode switch Off-road mode cannot be selected Off-road mode is activated when switch has not been selected Air supply unit air control valves Valves open or short circuit Failure Effect Vehicle does not level or levels unevenly Air supply unit compressor Failure Faulty relay, harness fault or compressor fault Effect Vehicle does not level upwards 180 (G538475) Technical Training

182 Lesson 4 Diagnostics Discovery Series II Connector Details ECU Connectors Connector Information Connector Pin Detail - C0504 Pin No Description Input or Output C C C C Battery supply Ignition supply 'K' line (diagnostics) Ground Input Input Input/Output Input Connector Pin Detail - C0654 Pin No Description Input or Output C C C C C C Left height sensor supply Left height sensor ground Left height sensor feedback signal Right height sensor supply Right height sensor ground Right height sensor feedback signal Output Input Input Output Input Input Technical Training (G538475) 181

183 Discovery Series II Lesson 4 Diagnostics Connector Pin Detail - C0655 Pin No Description Input or Output C C C C C C C C C C Driver's door switch Passenger and tailgate door switches Left air valves Right air valve Exhaust valve Air compressor (SLS relay) Audible warning SLS warning lamp ORM switch /ORM warning lamp Remote handset raise /lower signal Input Input Output Output Output Output Output Output Input/Output Input 182 (G538475) Technical Training

184 Lesson 4 Diagnostics Discovery 3 / LR3 DISCOVERY 3 / LR3 System Checks The air suspension control module can store fault codes which can be retrieved using the T4 diagnostic unit. Diagnostic information is obtained via the diagnostic socket which is located in the lower instrument panel closing panel, on the driver's side, below the steering column. The diagnostic socket allows the exchange of information between the various control modules on the bus systems and T4 system or diagnostic tool. This allows the fast retrieval of diagnostic information and programming of certain functions using the T4 system. Fault Detection The air suspension control module performs fault detection and plausibility checks. Fault detection is limited to faults that the control module can directly measure: Sensor electrical hardware faults Valve electrical hardware faults Sensor and actuator supply faults Bus failures Control module hardware errors Plausibility checks are checks on signal behavior, as follows: Height Changes Technical Training (G538475) 183

185 Discovery 3 / LR3 Lesson 4 Diagnostics Average height does not change correctly Height changes too slowly Gallery Pressure Does not increase fast enough when reservoir filling requested Increases when system is inactive Too low when lifting is requested Increases too rapidly when filling reservoir Does not decrease when gallery is vented Pressure varies too much when inactive Compressor Temperature Sensor voltage too large - head and brush sensors (short circuit to battery) Takes too long to be readable after suitable compressor run time - head and brush sensors Does not increase when compressor active - head sensor only Sensor Activity Signal floating Constant articulation when moving When a fault is detected, the air suspension control module will attempt to maintain a comfortable ride quality and where possible will retain as much functionality as possible. The system functionality depends on the severity of the fault. Fault Categories Faults are categorized into order of severity and effect on the system as follows: 1 = Minor fault 5 = Major fault Height sensor faults (hardware faults) and reservoir valve block failure Retain full functionality with no 'refinements' Cross-link valves inoperative No compensation for uneven surfaces Pressure sensor faults, compressor faults, corner valves stuck shut Road speed signal not available Vehicle returns to on-road mode height when next requested Levels at 'current' height Reservoir valve stuck open, exhaust valve stuck shut if below on-road mode height, corner valves stuck open if above on-road mode height Vehicle returns to on-road mode height when next requested Does not level at 'current' height Failure of multiple height sensors, cross-articulation when driving, calibration corrupted Vehicle lowers to bump stops ABS module failure, CAN bus failure If the air suspension control module loses communications with the ABS module or the ABS module reports a fault, the air suspension control module immediately returns to the 'default' height, which is below the on-road ride height Once at the default height, the control module will continue to level the vehicle at this height It is unlikely that the fault will be in the air suspension control module When the fault is repaired, the air suspension control module will resume full functionality but the error will remain in the control module memory For major faults the control module will not level the vehicle at the 'current' ride height. The control module freezes height changes until it receives a manual or automatic request for height change. 184 (G538475) Technical Training

186 Lesson 4 Diagnostics Discovery 3 / LR3 The control module will return to standard height if possible and freezes once standard height is achieved. If the suspension is above the on-road height and the air suspension control module cannot lower the suspension, all height changes will be frozen. ABS / CAN Failures The control module will issue a message on the high speed CAN bus which is received by the instrument cluster which displays a maximum advisable speed in the message center. An immediate 'freeze' of the vehicle height is caused by the following: Failure of more than one height sensor - vehicle on bump stops Implausible articulation symptoms detected - vehicle on bump stops Valve or solenoid failure - corner valve stuck open below on-road height or exhaust valve stuck shut above on-road height Stuck corner or whole vehicle (diagnosed using plausibility of the sensor inputs) If height change is not possible, e.g. exhaust valve failed closed at off-road height or compressor failed at access height, the control module will not level or change height. If the air suspension control module has a hardware fault, the control module will disable all air suspension functions. Detectable hardware errors include memory error, control module failure and calibrations errors. Fault Messages The air suspension has two methods which it can use to inform the driver of a fault in the air suspension system; the air suspension switch LED's and the instrument cluster message center. When minor faults occur and the air suspension control module is able to level the vehicle to the 'current' ride height, the air suspension switch LED's will display the current ride height. If the air suspension control module suffers a major failure and there is no air suspension control, all the control switch LED's will remain off. If a fault occurs and the air suspension control module can determine the ride height and the vehicle is not above on-road height, the driver will be notified via an 'air suspension fault max speed 18.6 mph (30 km/h)' warning in the message center. If the control module cannot determine the height of the vehicle, or the vehicle is above on-road height, cannot be lowered and the vehicle speed is too high, an air suspension fault message is displayed. If the vehicle is restricted to on-road height an air suspension fault normal height only message is displayed. Technical Training (G538475) 185

187 Discovery 3 / LR3 Lesson 4 Diagnostics Connector Information Connector Pin Detail - C2030 Pin No Description Input or Output Rear control valve - Cross link valve - positive (+) Not used Not used Not used Air supply unit - Motor temperature sensor signal Not used Air supply unit - Motor temperature sensor - Ground Switch pack display - Raising LED Switch pack display - Lowering LED Switch pack display - On-road mode LED Rear control valve - Cross link valve - negative (-) Not used Not used Not used Not used Not used Switch pack display - Crawl mode LED Switch pack display - Access mode LED Not used Input Switch pack - Raise switch signal Output Not used Not used Not used Input Not used Input Output Output Output Input Not used Not used Not used Not used Not used Output Output Not used Input Connector Pin Detail - C2320 Pin No Description Input or Output Air supply unit voltage signal input from Air supply unit relay Reservoir control valve - Pressure sensor - 5 volt supply Reservoir control valve - Pressure sensor - Signal Input Output Input 186 (G538475) Technical Training

188 Lesson 4 Diagnostics Discovery 3 / LR3 Pin No Description Input or Output Reservoir control valve - Pressure sensor - Ground Air supply unit - Exhaust valve - Negative (-) Air supply unit - Exhaust valve - Positive (+) Not used Not used Input Input Output Not used Not used Connector Pin Detail - C2321 Pin No Description Input or Output V Permanent battery supply Compressor temperature sensor - Signal Front LH height sensor - 5 Volt supply Front LH height sensor - Signal Front LH height sensor - Ground Air supply unit relay coil - positive Air supply unit relay coil - ground Reservoir control valve coil - positive (+) Front control valve - RH corner valve - negative (-) Front control valve - RH corner valve - positive (+) Front control valve - LH corner valve - negative (-) Front control valve - LH corner valve - positive (+) Not used Front RH height sensor - 5V supply Front RH height sensor - signal Front RH height sensor - ground Compressor temperature sensor - ground Not used Not used Not used Input Input Input Input Input Input Input Not used Input Input Input Not used Not used Not used Technical Training (G538475) 187

189 Discovery 3 / LR3 Lesson 4 Diagnostics Pin No Description Input or Output Reservoir control valve coil - negative (-) Front control valve - cross link valve - positive (+) Front control valve - cross link valve - negative (-) Ground Input Input Input Connector Pin Detail - C0867 Pin No Description Input or Output Rear control valve - LH corner valve positive (+) Rear control valve - LH corner valve negative (-) Door status signal from CJB Switch pack - Lower switch signal Rear LH height sensor - 5v supply Rear LH height sensor - Signal Rear LH height sensor - Ground Rear RH height sensor - 5v supply Rear RH height sensor - Signal Rear RH height sensor - Ground Rear control valve - RH corner valve positive (+) Rear control valve - RH corner valve negative (-) Air suspension control - CJB signal Switch pack display - LED ground Switch pack display - LED high CAN IN positive (+) CAN OUT positive (+) CAN OUT negative (-) CAN IN negative (-) 12v ignition switch supply Output Input Input Input Output Input Input Output Input Input Output Input Input Input Output Input Output Input Output Input 188 (G538475) Technical Training

190 Lesson 4 Diagnostics Discovery 3 / LR3 Control Schematic Technical Training (G538475) 189

191 Discovery 3 / LR3 Lesson 4 Diagnostics Item Description Item Description 1. Fuse 26E (20 amp) 12. Exhaust valve solenoid 2. Fusible link 11E (30 amp) 13. Air suspension control module 3. Ignition switch 14. Central junction box (CJB) 4. Fuse 35P (5 amp) 15. Reservoir control valve 5. Fusible link 10E (60 amp) 16. Air suspension control switch 6. Air supply unit relay 17. Front valve block 7. Fuse 3E (5 amp) 18. Rear valve block 8. Air supply unit 19. RHR height sensor 9. Compressor temperature sensor 20. LHR height sensor 10. Motor 21. RHF height sensor 11. Motor temperature sensor 22. LHF height sensor 190 (G538475) Technical Training

192 Lesson 4 Diagnostics 2006MY Range Rover (LM) 2006MY Range Rover (LM) System Checks The air suspension control module can store fault codes which can be retrieved using T4. The diagnostics information is obtained via the diagnostic socket which is located in the instrument panel, in the drivers stowage tray. The socket is secured in the instrument panel and protected by a hinged cover. The diagnostic socket allows the exchange of information between the various control modules on the bus systems and T4 or a diagnostic tool. This allows the fast retrieval of diagnostic information and programming of certain functions using T4. The air suspension control module performs fault detection and plausibility checks. Fault detection is limited to faults that the control module can directly measure, as follows: Sensor electrical hardware faults Valve electrical hardware faults Sensor and actuator supply faults Bus failures Control module hardware errors. Plausibility checks are checks on signal behaviour, as follows: Average height does not change correctly Height changes too slowly Gallery Pressure Does not increase fast enough when reservoir filling requested Increases when system is inactive Too low when lifting is requested Technical Training (G538475) 191

193 2006MY Range Rover (LM) Lesson 4 Diagnostics Increases too rapidly when filling reservoir Does not decrease when gallery is vented Pressure varies too much when inactive. Compressor Temperature Sensor voltage too large - head and brush temperature sensor (short circuit to battery) Takes too long to be readable after suitable compressor run time - head and brush temperature sensor Does not increase when compressor is active - head temperature sensor only. Sensor Activity Signal floating Constant articulation when moving. When a fault is detected, the control module will attempt to maintain a comfortable ride quality and where possible will retain as much functionality as possible. The system functionality depends on the severity of the fault. Faults Faults are categorised into order of severity and effect on the system as follows: Height sensor faults (hardware faults) and reservoir valve block failure Retain full functionality with no 'refinements', e.g. cross-link valves inoperative, no compensation for uneven surfaces. Pressure sensor faults, compressor faults, corner valves stuck shut Road speed signal not available Vehicle returns to on-road height when next requested Levels at 'current' height. Reservoir valve stuck open, exhaust valve stuck shut if below on-road height, corner valves stuck open if above on-road height Vehicle returns to on-road height when next requested Does not level at 'current' height. Failure of multiple height sensors, cross-articulation when driving, calibration corrupted Vehicle lowers to bump stops. ABS module failure, CAN bus failure If the air suspension control module loses communications with the ABS module or the ABS module reports a fault, the air suspension control module immediately returns to the default height, which is below the on-road height. Once at the default height, the control module will continue to level the vehicle at this height. It is unlikely that the fault will be in the air suspension control module. When the fault is repaired, the air suspension control module will resume full functionality but the error will remain in the control module memory. For major faults the control module will not level the vehicle at the 'current' ride height. The control module freezes height changes until it receives a manual or automatic request for height change. The control module will return to on-road height and freezes once on-road height is achieved. If the suspension is above the on-road height and the air suspension control module cannot lower the suspension, all height changes will be frozen. The control module will issue a message on the high speed CAN bus which is received by the instrument cluster which displays a maximum advisable speed in the message center. An immediate 'freeze' of the vehicle height is caused by one of the following: 192 (G538475) Technical Training

194 Lesson 4 Diagnostics 2006MY Range Rover (LM) Failure of more than one height sensor - vehicle on bump stops Implausible articulation symptoms detected - vehicle on bump stops Valve or solenoid failure - corner valve stuck open below on-road height or exhaust valve stuck shut above on-road height Stuck corner or whole vehicle (diagnosed using plausibility of the sensor inputs). If height change is not possible, e.g. exhaust valve failed closed at off-road height or compressor failed at access height, the control module will not level or change height. If the air suspension control module has a hardware fault, the control module will disable all air suspension functions. Detectable hardware errors include memory error, control module failure, calibrations errors. Fault Messages The air suspension has two methods which it can use to inform the driver of a fault in the air suspension system; the air suspension control switch LEDs and the instrument cluster message center. If the air suspension control module suffers a major failure and there is no air suspension control, all the control switch LEDs will remain unlit. If a fault occurs and the control module can determine the ride height and the vehicle is not above on-road height, the driver will be notified via a message in the message center. If the control module cannot determine the height of the vehicle, or the vehicle is above on-road height and cannot be lowered, a message is displayed and accompanied with a maximum speed message. The following table shows messages related to the air suspension system. Message SUSPENSION FAULT NORMAL HEIGHT ONLY SUSPENSION FAULT MAX SPEED 30MPH (50KPH) SLOW DOWN OR VEHICLE WILL RAISE SLOW DOWN OR VEHICLE WILL LOWER SUSPENSION WILL LIFT WHEN SYSTEM COOLED Other Warnings One chime Two chimes repeated every 30 seconds if speed exceeded Two chimes One chime None Meaning A fault has been detected in the air suspension system and only on-road (normal) height is available. A major fault has been detected in the air suspension system and it is unable to control the height correctly. Vehicle will automatically raise to on-road height if speed increases. Vehicle will automatically lower to on-road height from off-road height if speed increases. Air suspension compressor is cooling. Lifting will resume when compressor has cooled. Technical Training (G538475) 193

195 2006MY Range Rover (LM) Lesson 4 Diagnostics Message Other Warnings Meaning VEHICLE LIFTING SLOWLY EXTENDED MODE RESET HEIGHT IF CLEAR OF OBSTACLE SUSPENSION LOCKED AT ACCESS HEIGHT CLOSE DOORS TO CHANGE HEIGHT SPEED TOO HIGH TO CHANGE HEIGHT SUSPENSION FAULT START ENGINE TO RAISE VEHICLE SUSPENSION LOWERED Reservoir None One chime None None One chime One chime One chime None None Vehicle is lifting slowly from compressor only because reservoir is empty. Only displayed if lift time exceeds 12 seconds. Vehicle body has become grounded on an obstacle. Press air suspension rotary control switch downwards to exit the extended mode. Crawl mode has been selected. Re-select height if door was open for more than 90 seconds or air suspension height change is restricted because a door is open. A height change has been requested that is not allowed, e.g. vehicle speed to high to select off-road height. A fault has been detected in the air suspension system. The vehicle height can only be raised if the engine is running. The vehicle has lowered to access height because of a failure of another vehicle system. The control module then uses a software model to operate the compressor as required. The reservoir supplies pressurised air to the four air springs, via the reservoir valve block, to enable the air suspension system to raise the vehicle more quickly. The air suspension control module assumes the reservoir has sufficient pressure, which is measured before a vehicle raise is started. System Pneumatic Circuit The following schematic diagram shows the connection relationship between the air supply unit, the reservoir, the reservoir valve block, the cross-link valves and the air springs. 194 (G538475) Technical Training

196 Lesson 4 Diagnostics 2006MY Range Rover (LM) System Schematic Circuit Diagram Technical Training (G538475) 195