DIAGN PARA THE EUROPEAN. Can you count on your

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1 THE EUROPEAN DIAGN PARA Can you count on your fingers and toes the number of European vehicles you ve seen in your shop in the last six months? If the answer is Yes, then you probably figure you re not up to speed on the best way to diagnose problems when a late-model rolls in. Late-model European vehicles may have a warning light or a whole bunch of em you re not familiar with. You don t want to spend hours checking this, that and the other thing, only to find you can t get into self-diagnostics without a scan tool. On the other hand, you don t want to send those customers to the shop down the road, either. Well, here s some information to help you along. On the following pages you ll read which European systems are computer-controlled, which you can access without a scanner and which ones require a proprietary scan tool. This will let you know if a processor has turned on a warning light or if it s just a manual switch. It ll also help you realize what you re getting into in the way of time required for diagnoses, and afford your technicians the same courtesy. The eight nameplates we ll cover are (in alphabetical order) Audi, BMW, Jaguar, Land Rover, Mercedes, Saab, Volkswagen and Volvo. Let s get started. Audi Starting with its 1985 models, Audi s engine management systems have self-diagnostic capabilities. Previous to that, diagnostics are handled by simply checking the inputs and outputs directly at the engine ECU. Engine management faults, which cause the CEL (Check Engine light) to illuminate, can be diagnosed through self-diagnostics on 85 through 94 models. No special tools are required 44 March 2002

2 BY KERRY JONSSON OSTIC DOX There s a wealth of diagnostic information stored in European computers, but how much you can access is at the whim of the manufacturer. Here s a look at eight major nameplates, and what equipment you ll need to win the diagnostic wars. here; just a couple of jumpers and a homemade LED test light get you to blink out codes. Refer to your repair manuals or CD-ROM-based information system for the particulars. Unfortunately, in 1995, self-diagnostic procedures using this method were removed on all Audi vehicles except the S-series, which retained the blink code method. On all other models, if you want to use any of the self-diagnostic functions, you ll need a scan tool that s the equivalent of a VAG 1551/1, 2 or 3. Of course, all this became moot in 1996, when OBD II regs came on board. Audi started computer-controlling its automatic transmissions in 1994 on its high-end vehicles. Diagnostics for this system supposedly has blink code capability, but I have never been nor have I heard of anyone who has ever been successful at pulling codes this way. Once again, a scan tool is the weapon of choice. The same goes for Audi s ABS systems. Be aware that the Servotronic March

3 THE EUROPEAN DIAGNOSTIC PARADOX The proliferation of computer controls in more and more automotive systems these days has spawned the need for more warning lights than ever. Don t assume it s a matter of jump pin A to pin B and a code will magically appear. Sometimes software interfaces are necessary for even the most basic diagnoses. Photos: Kerry Jonsson brake and power steering systems used on some vehicles have electronic controls but no self-diagnostic capabilities. SRS systems have self-diagnostics, but require a scan tool to access the data. In the mid- 90s, Audi started adding self-diagnostics to the instrument cluster and traction control systems, which were available on some models. Like most everything else with Audis, you ll need a scan tool to access the info. Audi climate control systems have always had a self-diagnostic function, and while a scanner is nice to have, it s not an absolute necessity. Up until the 97 models, you can use the control panel to access faults in the climate control system. Once again, refer to your repair manuals or CD system for the specifics. It s quite apparent that despite OBD II, there s still a need for a proprietary scan tool to access most of Audi s late-model computer systems. BMW If you see an illuminated CEL on a pre- 96 BMW, you needn t worry. Five stabs at the gas pedal and the engine ECU will spit out codes. On 12-cylinder models, stomp on the pedal six more times to get codes from the second control unit of the split system. Once OBD II regs kicked in, however, these options were eliminated, with scanners the only game in town for accessing engine management system faults. Since the 1990 model year, BMW has added many other computer-controlled systems, and every one of them requires a scan tool to tap into self-diagnostic functions. These systems include transmission control (EGS), antilock brakes (ABS), stability control (ASC), traction control (+T), cruise control, electronic throttle (EML), air bags (SRS), electronic suspension (EDC), etc. Body control modules were added in the late 90s and, you guessed it, require a scan tool, as well. Jaguar Fuel injection system diagnostics have been available on Jags since 1986 for its 12-cylinder two-door models and since 88 for sedans, both through the control panel. This method was retained on both models through the 95 model year. A year later, OBD II regs kicked in. A scan tool is required for transmission diagnostics for all pre-obd II Jags. Steering and suspension system problems are straightforward repairs; nothing fancy here. You can also access ABS self-diagnostics with- 46 March 2002

4 Sometimes there s no warning light to signal a problem, but a Driver Information Center, to alert the driver of any system malfunction. However, don t always expect these DICs to tell you what s gone wrong. out a scanner on XJSs and XJ6 models by jumping the diagnostic connector and getting codes to spit out. After 94, a factory scan tool is needed for ABS work. Beginning in the mid- 90s, Jaguar allowed self-diagnostic information for the climate control system to be accessed through the control panel itself. However, starting with 88 models, all other systems that have self-diagnostic capabilities, such as the SRS and body control systems, require a scan tool interface. Land Rover Land Rover has required its own scan tool interface for almost all their systems, starting in about 1989, with a few notable exceptions. Fuel injection codes, for instance, can be read off a diagnostic readout box on 1990 through OBD II vehicles. ABS codes can be accessed on pre- 90 vehicles by jumping a diagnostic pin to ground and watching the ABS light blink out codes. All other systems require dedicated Land Rover test equipment. Note that there are some companies that produce software to interface with Land Rover vehicles, but be forewarned, it can be expensive. Mercedes In 1992, Mercedes-Benz started altering its self-diagnostic options. Prior to that year, a duty cycle type reading could be accessed from a round diagnostic connector on the driver sside fender to get failure indications for the fuel injection system. Mercedes moved from an eight-pin to a 16-pin and finally to a 38-pin diagnostic connector as more computer controls were added to its vehicles. You can access codes from all Mercedes systems with a scan tool equivalent to its HHT factory tool, or with an impulse counter type tester through either the 16- or 38-pin diagnostic connectors. By 94, Mercedes eliminated the eight- and most 16-pin connectors and added the option of using either the 38-pin connector or the OBD II system to access codes for the engine and transmission controls. The impulse counter (a glorified logic probe) can be used to pull codes (not data) directly from these systems through the 38-pin diagnostic connector, but only on certain models. For instance, starting with chassis 202 and 210 (C-Class and E-Class), you can t use the counter to access the base module, electronic accelerator/cruise control/idle speed control module or the diagnostic module. You ll need a March

5 THE EUROPEAN DIAGNOSTIC PARADOX Land Rover s ABS system requires a proprietary scan tool called the Test Book to access self-diagnostic information from the module. This applies to all of the company s systems except engine management. scan tool for these. On other systems instrumentation (IC), antitheft, SRS, antilock brake (ABS), automatic slip control (ASR), brake assist (BAS) and electronic stability control (ESP), for example a scan tool will be required, as well. However, the body control (CAN), door lock and climate control systems can still be accessed with the impulse counter. Note that the climate control system on Mercedes models can also be tapped into through the control panel by pushing a series of buttons. Once again, consult your repair information system for the specifics. Saab Saab started self-diagnostics, which used the blink code method for engine management systems, in 1988 on its 2.4 system, in 90 on its system (only in that year) and in 91 for the system. The earlier 2.2 LH-Jetronic system does not have the capability to diagnose itself. So when the CEL comes on on these vehicles, the only way to diagnose the system is to check the inputs and outputs directly at the ECU. The EZK ignition systems had the same blink code method up to 93, after which Saab switched to OBD II. New combined fuel and ignition management systems were introduced in Saabs in 93 (Trionic) and 95 (Motronic), and both had codes you could flash out. The ABS systems on 90 and 91 vehicles had the same capability. Saab s a/c systems have the ability to display codes on the control panel, if the vehicle has climate control. Any system not mentioned above requires either a special tester for that system only, or the ISAT factory scan tool (or its equivalent). Volkswagen In 1989, Volkswagen started using selfdiagnostics on its engine management systems for California vehicles only. In 91, VW s federal models got the same capability, which you can access without a scan tool. You ll find the procedure in your repair manuals. Every VW engine management system after 95 requires OBD II test equipment. VW s automatic transmissions became electronically controlled in A scan tool equivalent to the factory VAG 1551 is required to access transmission codes and data. Antilock brakes were introduced on Jettas in 89 and on all other models in 48 March 2002

6 Even Mercedes has several layers of self-diagnostic capability. With a proprietary impulse counter (a fancy logic probe) you can pull codes from this diagnostic connector on the driver s-side fender, but no live data. In the mid- 90s, this method was phased out and scan tools are now required. Luckily, some aftermarket manufacturers now make these tools and software available. 90. Simply put, every ABS system in a Volkswagen vehicle needs a scan tool to access self-diagnostics. Ditto for every model with SRS and cruise control since the early to mid- 90s. Volvo Volvo started using self-diagnostics on its engine management systems in 1988 on 700 series cars. For every model year up to and including the 95s (except 200 series DLs and GLs), you can flash out fault codes, as well as perform input and output testing, through the diagnostic connector. As electronic systems were added to more Volvo models, more socket options and even more diagnostic connectors were added, as well. In diagnostic connector A, socket 1 is for the electronic transmission, socket 2 for fuel injection or Motronic, socket 3 for ABS, socket 6 for ignition and socket 7 for the instrument cluster. In connector B, socket 1 is for the climate control, socket 2 for cruise control, socket 5 for the SRS and socket 6 for the memory seats. Once the diagnostic connector was moved from under the hood to in front of the shifter in the console in 1996, you needed a scan tool to do everything from checking for codes to resetting the maintenance light. Maintenance light resetting, by the way, was returned to a push-button method in the very late 90s. Note that 200 series DLs and GLs have self-diagnostic capability only for fuel and ignition control. All other systems except SRS require a proprietary tool. For 90 to 93 models with air bags, just jump a terminal to ground to get codes to spit out of the system. Thanks to OBD II, the European car market is moving more toward scan-based diagnostics, which is good news for service techs. But remember, OBD II requires that only emissionsrelated information be available. That leaves many other computer-controlled systems inaccessible, unless you make the investment in dedicated test gear. Of course, things could change for the better. But until they do, choose your diagnostic battles wisely, or risk losing the war! Visit to download a free copy of this article. Copies are also available by sending $3 for each copy to: Fulfillment Dept., MOTOR Magazine, 5600 Crooks Rd., Troy, MI March