Euro On-Board Diagnostic System

Transcription

1 Service. Self-Sudy Programme 231 Euro On-Board Diagnosic Sysem For perol engines Design and Funcion

2 Now an inegral par of emission conrol and monioring in he USA, he On-Board Diagnosics (OBD II) sysem will also be inroduced wihin he European Union under he name Euro-On-Board Diagnosics (EOBD) from 1s January, Iniially, he sysem will be available for perol engines only, however, a version for diesel engines will follow in he foreseeable fuure. There are very few differences beween European varian of his diagnosic sysem and US OBD II. The only aleraions made were hose necessary o bring EOBD ino line wih European exhaus emission legislaion. Oher noeworhy feaures of EOBD are is cenral diagnosis inerface and self-diagnosis faul warning lamp. In his Self-Sudy Programme, we will show you new moniored vehicle sysems and he associaed diagnosics, aking Self-Sudy Programme 175 "On-Board Diagnosics II in he New Beele (USA)" as he basis. In his way, you will no have o read hrough repeiive maerial. NEW Imporan Noe The Self-Sudy Programme presens he design and funcion of new developmens. The conens are no subjec o updaing! Please always refer o he relevan Service Lieraure for curren inspecion, adjusmen and repair insrucions. 2

3 Table of conens Inroducion Legal framework Overview of EOBD New vehicle sysems EOBD varians Basic ypes of engine conrol uni Engine conrol unis and diagnosics Diagnosic rouines Self-diagnosis Readiness code Generic Scan Tool (OBD visual display uni) Vehicle Diagnosic, Tesing and Informaion Sysem VAS Funcion diagram Glossary Tes your knowledge

4 Inroducion Legal framework On 13h Ocober 1998, he European Union passed he EU Direcive 98/69/EC, according o which he inroducion of EOBD is mandaory for all member counries. This direcive has been adoped ino naional law in he Federal Republic of Germany. The inroducion of EOBD is no direcly coupled wih an exhaus emission sandard of he European Union (EU II, EU III, EU IV) or he Federal Republic of Germany (D2, D3, D4). Therefore, he arge dae for he inroducion of OEBD and he associaed ransiion period mus be considered independenly of he various exhaus emission sandards. Targe dae for inroducion of EOBD Wih effec from he 1s January, 2000, he auomobile indusry will be required o perform only one ype es for new perol-engined models if hey have EOBD. Transiion period The ransiion period perains o models which have been ype-esed prior o 31s December, 1999 and mee he EU II, D3 or D4 exhaus emission sandard. The buyer may sill regiser hese vehicles unil 31s December, 2000 and operae hem wihou EOBD wih no resricions. Wih effec from his dae, exising models will be required o have EOBD for iniial regisraion purposes (buyer). The EOBD legislaion does no affec vehicles which were regisered by he buyer prior o 31s December, Type ess in he auomobile indusry New models wihou EOBD New models wih EOBD Year 2000 Year 2001 New vehicles wihou EOBD New vehicles wihou EOBD (wih EU II, D3 or D4) New vehicles wih EOBD Homologaion of new vehicles of buyers 231_002 4

5 Overview of EOBD The visible elemens of EOBD are he self-diagnosis faul warning lamp K83 and he diagnosis inerface in he passenger cabin. The engine conrol uni performs all oher funcions and diagnosic operaions auomaically. The driver does no noice he ongoing checks on he sysems in his vehicle which are relevan o exhaus emissions. This means ha no much changes for he driver of a vehicle wih EOBD, however service personnel will be required o familiarize hemselves wih new auomoive echnologies and he associaed procedures. Self-diagnosis faul warning lamp K83 If a faul impairing exhaus gas qualiy occurs on board he vehicle, he faul is saved o he faul memory and he self-diagnosis faul warning lamp is acivaed. 231_011 EOBD sores he "on" period of he selfdiagnosis faul warning lamp (in erms of kilomeres ravelled). If here is a risk of caalys damage due o misfiring, he self-diagnosis faul warning lamp flashes. Diagnosis inerface Sored EOBD daa can be read ou via he diagnosis inerface. The faul codes are sandardised so ha daa can be acquired using any Generic Scan Tool (OBD visual display uni). The diagnosis inerface mus be wihin easy reach of he driver's sea. 231_012 EOBD checks: - The elecrical funcions of all componens which are imporan for exhaus gas qualiy. - The funcioning of all vehicle sysems which have a bearing on exhaus gas qualiy (e.g. lambda probes, secondary air sysem). - The funcioning of he caalys. - For misfiring. - The CAN daabus. - For rouble-free operaion of he auomaic ransmission. 5

6 Inroducion New vehicle sysems Before we describe he deails of EOBD o you, i is worh menioning he new vehicle sysems. Since he publicaion of he Self-Sudy Programme 175 "On-Board Diagnosics II in he New Beele USA", several vehicle sysems moniored by EOBD have been improved. For funcional descripions of he vehicle sysems which are no described in deail in his Self-Sudy programme, please refer o Self-Sudy Programme 175. The broadband lambda probe (LSU Lambda Probe Universal) is a new generaion of lambda probes ha are deployed before he caalys. The name reveals he goals ha were se for he developmen of his probe. The lambda value is represened by near-linear rises in curren, and no longer by an abruply rising volage curve (which is he case wih he sep ype lambda probe). As a resul, i is possible o measure he lambda value over a larger measuremen area (broader band). The convenional finger probes (LSH Lambda Probe Heaing) or Planar Lambda Probe (LSF Lambda Probe Fla) are also known as sep probes because of heir sep-like volage curves. Broadband lambda probe Ι rich mixure λ 1 Curren Ι lean mixure 231_005 Lambda A sep ype lambda probe is used for he probe afer he caalys. The sep-like measuremen area of a sep ype lambda probe around he value lambda=1 (λ=1) is sufficien for he probe afer he caalys o perform is monioring funcion. Sep ype lambda probe U rich mixure lean mixure λ 1 Volage U 231_004 Lambda 6

7 Funcion The broadband lambda probe acquires and evaluaes lambda values differenly o he sep ype lambda probe. Therefore, he lambda value is deermined from a change of curren, no from a change of volage. However, he physical processes are idenical. To show he funcional differences clearly, boh sysems are described briefly below. Sep ype lambda probe Ambien air Exhaus gas Elecrodes Probe volage mv Engine conrol uni The core of his probe is a ceramic body coaed on boh sides (Nerns cell). These coaings ac as elecrodes; one elecrode layer is in conac wih he ambien air and he oher is in conac wih he exhaus gas. The differenial beween he oxygen concenraion in he ambien air and in he exhaus gas resuls in a volage beween he elecrodes. This volage is evaluaed in he engine conrol uni in order o deermine he lambda value. 231_032 Exhaus gas Diffusion duc Pump cell Pump curren A 450 mv Broadband lambda probe This probe also uses wo elecrodes o generae a volage, which is he resul of differen oxygen concenraions. The difference o he sep ype lambda probe is ha he volage of he elecrodes is kep consan. A pump cell (miniaure pump) supplies he elecrode on he exhaus side wih enough oxygen o mainain a consan volage of 450 mv beween he wo elecrodes. The engine conrol uni convers he power consumpion of he pump ino a lambda value. Ambien air Probe volage Measuremen area 231_033 7

8 Inroducion Examples showing how he broadband lambda probe is conrolled The fuel/air mixure is becoming leaner. This means ha he oxygen conen in he exhaus gas is rising and he pump cell, while operaing a a consan delivery rae, is pumping more oxygen ino he measuremen space han can escape hrough he diffusion duc. As a resul, he oxygen-o-ambien air raio changes and he volage beween he elecrodes drops. A 450 mv 231_036 To resore he volage beween he elecrodes o 450 mv, he oxygen conen mus be reduced on he exhaus side. To achieve his effec, he pump cell mus pump less oxygen ino he measuremen space. The pump delivery rae, herefore, is reduced unil he volage is resored o 450 mv. The engine conrol uni convers he power consumpion of he miniaure pump ino a lambda conrol value and alers he mixure composiion accordingly. A 450 mv 231_037 8

9 A 450 If he fuel/air mixure is oo rich, he oxygen conen in he exhaus gas drops. As a resul, he pump cell, while operaing a a consan delivery rae, is delivering less oxygen ino he measuring area and he volage beween he elecrodes is rising. In his case, more oxygen is escaping hrough he diffusion duc han he pump cell can deliver. mv 231_038 A The delivery rae of he pump cell mus be increased in order o increase he oxygen conen in he measuring area. As a resul, he elecrode volage is resored o 450 mv and he power consumpion of he pump cell is convered ino a lambda conrol value by he engine conrol uni. 450 mv 231_039 The pump acion of he pump cell is a purely physical process. No mechanical componens are used for he funcion. The pump cell is represened above symbolically. A posiive pump cell volage aracs negaive oxygen ions hrough he oxygen-permeable ceramic maerial. The broadband lambda probe and he engine conrol uni are a single sysem. I is imporan ha he lambda probe maches he engine conrol uni. 9

10 Inroducion Design Sensor elemen in cross secion 5 Pump cell wih elecrodes a 4 b 1 c d _042 1 Nerns cell wih elecrodes 2 Probe heaer 3 Ambien air duc 4 Measuremen space 5 Diffusion duc a b c d Symbolic represenaion Elecrode (anode) Curren source Ceramic maerial Elecrode (cahode) Two makes of lambda probe are fied. Elecrical circui (NTK) Elecrical circui (Bosch) J... J... G39 G39 231_ _059 Effecs of failure of probe before caalys If he signal from he lambda probe fails, no lambda conrol akes place and lambda adapion is disabled. The fuel ank purging sysem eners emergency running mode. The secondary air and caalys diagnoses are disabled. The engine conrol uni uses a mapped conrol as an emergency funcion. The broadband lambda probe may only be replaced complee wih cable and connecors. 10

11 Elecrical exhaus gas recirculaion sysem The exhaus gas recirculaion sysem is primarily used o increase fuel efficiency in lowdisplacemen engines. As a resul of he recirculaing exhaus gases, he engine is required o induce less air. The resuling savings in sucion work improve fuel efficiency. 231_046 Exhaus gas recirculaion valve N18 (new version) Funcion 2 3 Two valves were previously used o conrol he exhaus gas supply: - Exhaus gas recirculaion valve N18 - EGR valve 1 4 The EGR valve was acivaed elecrically by he engine conrol uni and ransferred a corresponding vacuum o he EGR valve. The vacuum caused he EGR valve o open, allowing exhaus gas o ener he inake manifold. 231_047 1 Engine conrol uni J... 2 Exhaus gas recirculaion valve N18 3 EGR valve 4 Caalys 11

12 Inroducion Only one valve is sill used for elecrical exhaus gas recirculaion: - Exhaus gas recirculaion valve N18 This valve is acivaed direcly by he engine conrol uni and elecromagneically adjuss he opening sroke for exhaus gas recirculaion. The inegraed exhaus gas recirculaion poeniomeer signals he acual opening sroke of he valve o he engine conrol uni Engine conrol uni J... 2 Exhaus gas recirculaion valve N18 and exhaus gas recirculaion poeniomeer G212 3 Ven 4 Caalys 231_043 The EGR valve and he exhaus gas recirculaion valve are combined in he elecrical exhaus gas recirculaion sysem. Elecrical circui Effecs of failure of valve J... If he valve fails in he open posiion, he engine shus down a idling speed and can no longer be sared. If he valve remains closed, he failure has no effecs on vehicle operaion. The faul will neverheless be deeced and saved. N18 G _056 12

13 Elecric hrole drive The hrole valve was previously adjused mechanically by means of a Bowden cable. The hrole valve was only acuaed by elecric moor when he engine was running a idling speed or when a cruise conrol sysem was in use. Use of he elecrical hrole conrol enables he engine conrol uni o adap he hrole valve posiion o he given basic condiions in any driving siuaion. Funcion The driver's preference or he signals from he acceleraor pedal module are ransferred o he engine conrol uni. Making allowance for all auxiliarysignals, he engine conrol uni hen deermines how he orque requiremen can bes be implemened. The orque requiremen is implemened via he elecromoively adjusable hrole valve, he igniion sysem and he fuel injecion sysem. Malfuncions are indicaed via he elecric hrole conrol faul lamp. For example, auxiliary signals are supplied by: - The cruise conrol sysem, - The air condiioning sysem, - The idle speed conrol, - The lambda conrol, - The auomaic ransmission and - ABS/ESP. For deailed informaion regarding he elecric hrole drive, please refer o Self-Sudy Programme 210. Auxiliary signals Acceleraor pedal module Throle valve conrol uni J338 Igniion, fuel injecion Elecric hrole conrol faul lamp K132 (EPC = Elecronic Power Conrol) 231_008 13

14 Inroducion Inegraed shaf sealing ring sensor In several engines, a new Generaion of engine speed sender G28 is in use he Inegraed shaf sealing ring sensor (IWDS Inegrierer Wellendichring-Sensor). The sender is mouned in a sealing flange for he crankshaf on he gearbox side of he engine. The sender wheel (60-2 eeh) is press-fied on he crankshaf in a precisely defined posiion. The IWDS sysems are made by wo differen manufacurers and, herefore, may differ in erms of heir design. Crankshaf Engine speed sender G28 Engine side Gearbox side Sender wheel Sealing flange 231_030 Crankcase Elecrical circui Effecs of failure J... Maximum engine speed is reduced and he engine conrol uni calculaes a defaul value for engine speed from he signal supplied by Hall sender G40. G28 231_031 14

15 EOBD varians The descripion and explanaion of EOBD is more deailed han he descripions of individual componens or sysems. The difficulies involved quickly become apparen when one considers ha EOBD is no an inegraed vehicle sysem; many individual sysems and componens are coninously checked for correc funcioning. The various vehicle ypes, engines, engine conrol unis, ec., also have o be aken ino accoun. To simplify maers, we will provide you wih an overview of he various ypes of engine conrol uni and engine conrol unis before explaining he es procedures. Basic ypes of engine conrol uni Basically, engine managemen sysems are classified according o how operaing saes in he inake manifold (air mass or inake manifold pressure) are deermined. This classificaion is no referred o specific engine conrol uni manufacurers, because hey usually supply boh ypes. The inake air quaniy or inake manifold pressure are required o calculae - The igniion poin - The injecion quaniy - And for EOBD monioring of almos all componens. Inake manifold pressure sysems Igniion Inake manifold pressure sender G71 Injecion In hese engine managemen sysems, inake air quaniy is deermined wih he aid of he inake manifold pressure sender. These sysems do no have an air-mass flow meer. EOBD 231_034 15

16 EOBD varians Air mass sysems As he name suggess, he ask of he air-mass flow meer is o deermine he inake air quaniy. The inake manifold pressure sender is no longer required for his purpose. Igniion Air-mass flow meer G70 Injecion EOBD 231_035 Turbocharged engines have air-mass flow meers and inake manifold pressure senders because he inake manifold pressure sender is also required o measure he charge pressure. Engine conrol unis and air flow meering The various engine conrol unis will now be assigned o he ypes of engine conrol uni (air flow meering in inake manifold). Engine conrol unis Bosch Moronic ME Air flow meering Inake manifold pressure Bosch Moronic ME 7.1 Air mass Bosch Moronic ME 7.5 Air mass Bosch Moronic ME Air mass Magnei Marelli 4LV Inake manifold pressure Siemens Simos 3 Air mass 16

17 Engine conrol unis and diagnosics In he following able, he individual EOBD diagnosic rouines are assigned o he engine conrol unis. I can be seen ha no all engine conrol unis use he same diagnosic rouines wihin he EOBD. Engine conrol unis Diagnosic rouines Siemens Simos 3 Magnei Marelli 4LV Bosch Moronic M Comprehensive Componens Monioring Volage curve shif and adapion of probe before caalys Lamdba probe heaer diagnosis Reacion ime diagnosis of probe before caalys Conrol limi diagnosis of probe afer caalys Moion diagnosis of probe afer caalys Caalyic conversion diagnosis Fuel ank purging sysem Flow rae diagnosis Fuel ank purging sysem Modulaion diagnosis Misfiring Irregular running mehod Misfiring Momen analysis mehod Exhaus gas recirculaion Pressure diagnosis Elecric hrole drive CAN daabus Daa diagnosis Secondary air Flow rae diagnosis Charge pressure limi diagnosis 17

18 EOBD varians Engine conrol unis Diagnosic rouines Bosch Moronic ME 7.1 Bosch Moronic ME 7.5 Bosch Moronic ME Comprehensive Componens Monioring Volage curve shif and adapion of probe before caalys Lamdba probe heaer diagnosis Reacion ime diagnosis of probe before caalys Conrol limi diagnosis of probe afer caalys Moion diagnosis of probe afer caalys Caalyic conversion diagnosis Fuel ank purging sysem Flow rae diagnosis Fuel ank purging sysem Modulaion diagnosis Misfiring Irregular running mehod Misfiring Momen analysis mehod Exhaus gas recirculaion Pressure diagnosis Elecric hrole drive CAN daabus Daa diagnosis Secondary air Flow rae diagnosis Charge pressure limi diagnosis 18

19 Diagnosic rouines Many of he diagnosic rouines were previously explained and described in Self-Sudy Programme 175. To avoid repeiion, new diagnosic rouines will be deal wih in deail and known rouines will be menioned only. Known rouines are indicaed by a red "icon" and he ex "SSP 175". SSP 175 Comprehensive Componens Monioring (Line-conduced fauls) This diagnosic rouine moniors he funcioning of all sensors, acuaors and oupu sages ha are relevan o exhaus emissions wihin he framework of he EOBD. For deails of he individual componens, refer o he funcion diagrams. SSP 175 Componens are esed according o he following crieria: - Check of inpu and oupu signals (plausibiliy) - Shor circui o earh - Shor circui o posiive - Open circui Lambda probe Volage curve shif diagnosis and adapion of he probe before he caalys Ageing or poisoning can cause a shif in he volage curve of he probe before he caalys. This shif is deeced by he engine conrol uni and can be compensaed (adaped) wihin defined bounds.the diagnosis sequence is basically he same despie he new broadband lambda probe. SSP 175 Lamdba probe heaer diagnosis By measuring he probe heaing resisance, he engine conrol uni checks he hea oupu of he lamdba probe heaer for correcness. SSP

20 Diagnosic rouine Reacion ime diagnosis of probe before caalys The reacion ime of he probe before he caalys can also deeriorae due o ageing or poisoning. The procedure for diagnosis of hese fauls was previously explained in Self-Sudy Programme 175. However, he signals from he probe before he caalys have changed due o he use of broadband lambda probes. Hence, he descripion of his diagnosis rouine wih he curren signals from probe before he caalys. Modulaion of he fuel/air mixure by he engine conrol uni is prerequisie for reacion ime diagnosis. This modulaion akes he form of sligh flucuaion beween lean and rich mixure. I is induced arificially by he engine conrol uni, because he lambda value can be conrolled by using he broadband lambda probe o such as high degree of accuracy ha i is possible o mainain a consan value of λ=1. For opimal operaion, however, he caalys requires he mixure composiion o flucuae slighly. Therefore, he engine conrol uni modulaes his mixure when a broadband lambda probe is being used. Mixure modulaion of he engine conrol uni U rich mixure λ=1 lean mixure U = volage, = ime 231_048 The signal from he broadband lambda probe is specified here as volage U, because he Vehicle Diagnosic, Tesing and Informaion Sysem VAS 5051 convers he acual oupu signal (curren inensiy Ι) ino a volage and displays his value. 20

21 The signal from he probe before he caalys follows modulaion of he fuel/air mixure by he engine conrol uni. The signal from he probe before he caalys can no longer follow modulaion of he fuel/air mixure. Probe before caalys OK Probe before caalys no OK 1 231_ _045 U U U U 2 3 U = volage, = ime 1 Engine conrol uni 2 Probe before caalys 3 Probe afer caalys 21

22 Diagnosic rouines Conrol limi diagnosis of probe afer caalys When he fuel/air mixure is of opimal composiion, he volage of he probe afer he caalys will be in he region of λ=1. If he probe afer he caalys produces a higher or lower average volage, his indicaes ha he fuel/air mixure is oo rich or oo lean. The engine conrol uni herefore changes is lambda conrol value (his affecs he fuel/air-mixure composiion) unil he probe afer he caalys again signals λ=1. This lambda conrol value has defined conrol limis. If hese conrol limis are exceeded, EOBD assumes ha here is a faul in he probe afer he caalys or in he exhaus sysem (secondary air). Lean fuel/air mixure and correc conrol The probe afer he caalys signals a rise in oxygen concenraion in he exhaus gas o he engine conrol uni hrough a volage reducion. The engine conrol uni hen increases he lambda conrol value, and he fuel/air mixure is enriched. The volage of he probe afer he caalys rises and he engine conrol uni is again able o reduce he lambda conrol value. This conrol loop exends over a lenghy vehicle operaing period. m 1 Conrol loop afer caalys OK 231_015 U λ=1 2 m = lambda conrol value, U = volage, = ime Lean fuel/air mixure and reaching of conrol limi value Conrol loop afer caalys no OK In his case, oo, he probe afer he caalys signals a rise in oxygen concenraion in he exhaus gas o he engine conrol uni hrough a volage reducion. The engine conrol uni hen increases he lambda conrol value, and he fuel/air mixure is enriched. Despie his enrichmen of he fuel/air mixure, he probe volage remains low (due o he faul) and he engine conrol uni coninues o increase he lambda conrol value unil he conrol limi is reached and he faul is deeced. m 231_014 U λ=1 1 Engine conrol uni 2 Probe afer caalys 22

23 Moion diagnosis of probe afer caalys The operaing performance of he probe afer he caalys is moniored also. To his end, he engine conrol uni checks he signals from he probe in acceleraion and overrun modes. When he vehicle is acceleraing, he fuel/air mixure is rich, he oxygen concenraion in he exhaus gas decreases and he probe volage mus rise. In overrun mode, he exac opposie applies: fuel feed is off, he oxygen concenraion in he exhaus gas increases and he probe volage mus drop. If he probe afer he caalys does no reac as expeced, he engine conrol uni assumes ha he probe afer he caalys is defecive. Example: vehicle acceleraion Probe afer caalys OK Probe afer caalys no OK 1 231_ _017 v U v U 2 v = vehicle road speed, U = volage, = ime 1 Engine conrol uni 2 Probe afer caalys Caalys Caalyic conversion diagnosis The engine conrol uni compares he volages of he probes before and afer he caalys. In his way, he degree of efficiency - and hence he performance - of he caalys can be deermined. SSP

24 Diagnosic rouines Fuel ank purging sysem Flow rae diagnosis When he fuel ank purging sysem is acivaed, he fuel/air mixure changes. If he acivaed charcoal caniser is full, he mixure will be rich. If he acivaed charcoal caniser is empy, he mixure will be lean. This change of mixure composiion is regisered by he probe before he caalys and serves as confirmaion ha he fuel ank purging sysem is funcioning properly. SSP 175 Modulaion diagnosis This diagnosis rouine carries ou checks cyclically. The engine conrol uni opens and closes acivaed charcoal filer sysem solenoid valve 1 slighly a defined inervals. The inake manifold pressure sender records he inake manifold pressure "modulaed" in his way and sends his pressure value o he engine conrol uni where i is correlaed and evaluaed. Fuel ank purging sysem OK Fuel ank purging sysem no OK 1 231_ _010 a P a P a = opening sroke of solenoid valve = ime, P = pressure 1 Engine conrol uni 2 Tank 3 Acivaed charcoal caniser 4 Acivaed charcoal filer sysem solenoid valve N80 5 Inake manifold pressure sender G71 24

25 Cylinder-selecive misfiring deecion sysem Irregular running mehod The engine speed sender can recognise irregulariies in engine speed caused by misfiring wih he aid of he crank disk. In combinaion wih he signal from he Hall sender (camshaf posiion), he engine conrol uni can locae he cylinder in quesion, save he faul o faul memory and acivae self diagnosis faul warning lamp K83. SSP 175 Momen analysis mehod As wih he irregular running mehod, he momen analysis mehod recognises cylinder-selecive misfiring from he signal supplied by he engine speed sender and he Hall sender. The difference beween hese wo mehods lies in he way he engine speed signal is evaluaed. The momen analysis mehod correlaes he irregular engine speed caused by igniion and compression wih fixed calculaions in he engine conrol uni. The basis for hese calculaions is he engine load and engine speed dependen orque, he cenrifugal mass and he resuling engine speed characerisic. The flucuaion in engine momen calculaed in his way is equally as conclusive as he resuls of he irregular running mehod, bu he engine speed characerisic is required o be analysed for each engine and sored in he engine conrol uni. Irregular engine speed Compression raio in cylinder 1 n For he sake of simpliciy, only he 1s cylinder will be examined in his example. During he compression cycle, he kineic energy of he engine is used o compress he fuel/air mixure. Engine speed decreases. n = engine speed, = ime 231_018 25

26 Diagnosic rouine The compression cycle is followed by he igniion cycle, and engine speed is increased. In his way, engine speed is made o flucuae by compression and igniion during each combusion cycle. Igniion in 1s cylinder n When all four cylinders are examined, he individual engine speed flucuaions are superposed o produce a resuling curve. This curve is measured by he engine speed sender and checked by he engine conrol uni agains a calculaion made wih characerisic engine daa. 231_019 Misfiring deecion using he engine speed signal no misfiring misfiring 1 n n 2 231_ _021 n = engine speed, = ime 1 Engine conrol uni 2 Engine speed sender G28 If he EOBD exhaus emission limis are exceeded due o misfiring, hen he self diagnosis faul warning lamp will be li coninuously. If, however, here is a risk of misfiring causing damage o he caalys and he engine is running wihin he criical load RPM range, he self diagnosis faul warning lamp iniially flashes and a shor ime laer he fuel feed o he corresponding cylinders is shu off. 26

27 Elecrical exhaus gas recirculaion Pressure diagnosis While exhaus gas is admied ino he inake manifold, he inake manifold pressure sender mus regiser a rise in pressure (less parial pressure). The engine conrol uni compares he pressure rise in he inake manifold wih he supplied exhaus gas quaniy and can hus deermine wheher he exhaus gas recirculaion (EGR) sysem is funcioning properly. This diagnosis is only carried ou in overrun mode, because injecion is deacivaed as a disurbing influence for measuremen and he inake capaciy of he engine is very high. 1 P+ EGR OK P+ EGR no OK 1 Engine conrol uni 2 EGR valve N18 3 Inake manifold pressure sender G71 P- P _ _023 P+ = excess pressure, P- = vacuum, = ime Elecric hrole drive The EOBD uses he elecrical hrole conrol diagnosic funcions which indicae a faul via he elecric hrole conrol faul lamp. If hese fauls sill exis during he nex one or wo driving cycles, he EOBD also acivaes he exhaus gas warning lamp. For more deailed informaion relaing o he diagnosic funcions of he elecrical hrole conrol, please refer o Self-Sudy Programme 210. The elecric hrole drive checks: - he funcion processor in he engine conrol uni - he acceleraor posiion sender - he angle senders for hrole valve drive - he brake ligh swich - he brake and cluch pedal swich - he vehicle road speed signal 27

28 Diagnosic rouines CAN daabus Daa diagnosis Each engine conrol uni knows he elecronic componens which exchange informaion via he CAN daabus in he vehicle. If he minimum number of messages is no received from a componen, a faul is deeced and saved. Furher componens which he CAN daabus uses include: - Conrol uni wih display uni in he dash panel inser - ABS conrol uni/esp - Auomaic gearbox conrol uni CAN daabus in proper service condiion All conneced componens (in his case: conrol unis) regularly ransmi messages o he engine conrol uni. The engine conrol uni recognises ha no messages are missing and daa is being exchanged properly. CAN daabus inerruped A componen canno ransmi informaion o he engine conrol uni. The engine conrol uni noices he missing informaion, idenifies he componen affeced and saves a corresponding faul message o faul memory. CAN daabus OK CAN daabus no OK 1 231_ _025 2 A B C A B C 1 Engine conrol uni 2 CAN daabus A-C Various conrol unis on board he vehicle 28

29 Secondary air sysem The performance of he secondary air sysem was previously esed via he lambda conrol value. This means ha he volage presen a he probe before he caalys mus indicae a lean mixure during secondary air discharge (λ>1) alhough he engine conrol uni is running he engine on a rich mixure. Flow rae diagnosis Since he inroducion of he broadband lambda probe, he signal from he probe before he caalys is used for diagnosis purposes, because he broadband lambda probe supplies more deailed measuremen resuls han he sep ype lambda probe for example. The acual air mass flow is calculaed and checked on he basis of he lambda differenial (lambda value before and during secondary air discharge). Secondary air sysem OK Secondary air sysem no OK 1 231_ _027 2 λ λ λ = lambda, = ime 1 Engine conrol uni 2 Secondary air pump relay J299 3 Secondary air inle valve N112 4 Secondary air pump V101 5 Combi valve 6 Probe before caalys 29

30 Diagnosic rouine Charge pressure conrol Charge pressure limis diagnosis In urbocharged engines, charge pressure is checked for exceeding he maximum permissible value wihin he framework of he EOBD. The check also serves o proec he engine, which mus no be overloaded by excessively high charge pressure. The charge pressure limi is exceeded The maximum permissible charge pressure is exceeded due o a faul in he charge pressure conrol. The inake manifold pressure sender signals he presence of charge pressure o he engine conrol uni, and he engine conrol uni deecs he faul. The proecive funcion is iniiaed In his case, i is no enough o indicae and save he faul. The exhaus gas urbocharger has o be deacivaed in order o avoid damaging he engine. For his purpose, he "wase gae" of he urbocharger is opened and he driving exhaus gases are divered hrough i. Charge pressure conrol no OK Charge pressure conrol no OK 1 231_ _029 P P Exhaus gas 4 P = pressure = ime 1 Engine conrol uni 2 Solenoid valve for charge pressure conrol N75 3 Exhaus gas urbocharger wih charge pressure conrol valve 4 Wase gae 5 Inake manifold pressure sender G71 30

31 Noes 31

32 Self diagnosis Readiness code All elecrical componens are coninuously checked for proper funcioning wihin he framework of he EOBD. In addiion, inegraed sysems (e.g. exhaus gas recirculaion sysem) are checked by non-coninuous diagnosic rouines. The readiness code is se o check wheher hese diagnoses were performed or no. The readiness code consiss of an 8-characer number code; a 0 (diagnosis performed) or a 1 (diagnosis no performed) can be assigned o each digi posiion. The readiness code does no check for fauls occurred; i indicaes only wheher diagnoses were performed. If he diagnoses produce no erroneous enries, he sysems are in proper service condiion. The engine conrol uni ses he readiness code when: - he readiness code is cancelled - he engine conrol uni is pu ino operaion for he firs ime. Vehicle self diagnosis Selec diagnosic funcion 02 - Inerrogae faul memory 03 - Acuaor diagnosis 04- Basic seing 05 - Clear faul memory 06- End of oupu 07 - Code conrol uni 08- Read daa block 09- Read individual measured value 10 - Adapaion 11 - Login procedure 15 - Readiness code 01 - Engine elecronics BB Marelli 4LV 3253 Code 31 Dealership number 5 Vehicle self diagnosis 15 - Readiness code Tes no complee Care should be aken o ensure ha he faul memory is no erased unnecessarily, because his also causes he readiness code o be rese or erased Engine elecronics BB Marelli 4LV 3253 Code 31 Dealership number 5 Tes Insrumens Go o Prin 231_058 Tes Insrumens Go o Prin Help The readiness code marked above represens he performance saus of he following sysems in he given order: 1. Caalys 2. Caalys heaing 3. Fuel ank purging sysem 4. Secondary air sysem 5. Air condiioning sysem 6. Lambda probe 7. Lamdba probe heaer 8. Exhaus gas recirculaion 32

33 Unused digi posiions of he readiness code are generally se o "0", because no all diagnoses are available in all vehicles. Read ou readiness code There are wo possible ways o read ou he readiness code. - Using any Generic Scan Tool (OBD visual display uni) or - Using he Vehicle Diagnosic, Tesing and Informaion Sysem VAS The procedures are explained on he following pages. Generae readiness code The readiness code can only be generaed by running he diagnoses. There are hree possible ways o do his: - Perform an NEFZ ("Neuer Europäischer Fahrzyklus" = new European driving cycle). However, he sandard workshop will be unable o perform he NEFZ on a roller dynamomeer upon compleion of repair work. - Run he vehicle in average operaing mode for long enough (his may necessiae several rips). - Using he VAS 5051 diagnosic sysem, perform a defined es rouine (shor rip) for each relevan vehicle sysem. The procedure is also explained in "Vehicle Diagnosic, Tesing and Informaion Sysem VAS 5051". Generic Scan Tool (OBD visual display uni) I mus be possible o read ou emission-relaed fauls and daa acquired by he engine conrol uni wihin he framework of he EOBD using any OBD visual display uni. Therefore, he deeced fauls are saved using an SAE code. This SAE code is used by all OBD sysems. SAE code: - P0xxx: Codes wih se faul exs defined by he SAE (Sociey of Auomoive Engineers) (same for all auomobile manufacurers) - P1xxx: Codes defined by auomobile manufacurers which are required o be repored o he governmen (hese codes are defined differenly for differen auomobile manufacurers) 33

34 Self diagnosis An OBD visual display uni can be pu ino operaion simply by connecing i o he diagnosis inerface in he passenger cabin. Communicaions beween he engine conrol uni and OBD visual display uni will be esablished auomaically. For faul ables for he SAE codes, refer o he Workshop Manual of he relevan engine conrol uni. re. Mode 3 and 7: For faul acknowledgemen, several diagnosis rouines require one or more rips unil he self diagnosis faul warning lamp is acivaed. An OBD visual display uni faciliaes he following funcions: - Mode 1: Read ou curren engine operaing daa (acual daa, readiness code). - Mode 2: Read ou operaing condiions which exised while saving a faul (only used if a faul has occurred). - Mode 3: Read ou emission-relaed fauls which have caused he self diagnosis faul warning lamp o be acivaed. - Mode 4: Erase faul code, readiness code and operaing condiions (Mode 2). - Mode 5: Display lambda probe signals. - Mode 6: Display measured values of non-permanenly moniored sysems (e.g. secondary air sysem, fuel ank purging sysem, exhaus gas recirculaion). - Mode 7: Read ou fauls which have sill no acivaed he self diagnosis faul warning lamp. - Mode 8: This mode is no used in Europe. - Mode 9: Display vehicle informaion (e.g. ID No., engine code, engine conrol uni ype, sofware idenificaion, sofware checksum). 34

35 Vehicle Diagnosic, Tesing and Informaion Sysem VAS 5051 Using VAS 5051, you can read ou he readiness code and perform he individual shor rips for he vehicle sysems required o generae he readiness code. Over and above he funcions of he OBD visual display uni, VAS 5051 provides addiional adjusmen, diagnosis and faul finding funcions. The faul-finding procedure can be opimised by accessing all key engine daa. Read ou readiness code 1s possibiliy: - Turn on he igniion. - Acivae "Vehicle self diagnosis" mode. - Selec he engine conrol uni wih address word "01". - Selec funcion "15 - Readiness code". 2nd possibiliy (Generic Scan Tool-Mode) - Turn on he igniion. - Acivae "Vehicle self diagnosis" mode. - Selec Generic Scan Tool Mode wih address word "33". - Selec Mode 1 "Read ou acual engine operaing daa". Perform shor rips Use funcion "04 Iniiae basic seing o invoke he individual shor rips. Differen procedures apply o he various engine conrol uni varians. For deails of he seps and precondiions for performing he shor rips of he various individual engine conrol uni varians, refer o he relevan Workshop Manuals. 231_041 35

36 Funcion diagram Example 1: 1.4-lr. 4V perol engine 55 kw/bosch Moronic ME J17 +12V +12V +12V +12V S S S S S G61 G188 G187 G186 J338 N30 N31 N32 N33 +5V J V N152 N80 G39 G V 231_053a Componens G28 Engine speed sender G39 Lambda probe (before caalys) G40 Hall sender G42 Inake air emperaure sender G61 Knock sensor I G62 Coolan emperaure sender G71 Inake manifold pressure sender G79 Acceleraor posiion sender G130 Lambda probe afer caalys G185 Acceleraor pedal posiion sender -2- G186 Throle valve drive G187 Throle valve drive angle sender -1- G188 Throle valve drive angle sender -2- G212 Exhaus gas recirculaion poeniomeer J17 Fuel pump relay J220 Moronic conrol uni J338 Throle valve conrol uni 36

37 +12V S G79 G185 A B C +5V +5V J220 Inpu signal Oupu signal Posiive Earh Daa line +5V G62 G28 G40 N18 G212 G42 G71 +12V 231_053b N18 EGR valve N30 Injecor, cylinder 1 N31 Injecor, cylinder 2 N32 Injecor, cylinder 3 N33 Injecor, cylinder 4 N80 Acivaed charcoal filer sysem solenoid valve 1 N152 Igniion ransformer A B C Signal o self diagnosis faul warning lamp K83 (in models daing from 2000, his signal is ransferred via he CAN bus) Road speed signal from conrol uni wih display uni in dash panel inser J285 CAN bus S Fuse 37

38 Funcion diagram Example 2: 1.4-lr. 4V perol engine 55 kw/magnei Marelli 4LV +12V J338 G88 G69 V60 N30 N31 N32 N33 +12V J17 +12V +5V J537 N V S N80 G39 G V 231_054a Componens G28 Engine speed sender G39 Lambda probe (before caalys) G40 Hall sender G42 Inake air emperaure sender G61 Knock sensor I G62 Coolan emperaure sender G69 Throle valve poeniomeer G71 Inake manifold pressure sender G79 Acceleraor posiion sender G88 G130 G212 J17 J537 J338 Throle valve posiioner poeniomeer Lambda probe afer caalys Exhaus gas recirculaion poeniomeer Fuel pump relay Conrol uni for 4LV Throle valve conrol uni 38

39 G61 G79 A B C +5V +5V +5V J537 Inpu signal Oupu signal Posiive Earh Daa line G62 G40 G28 G42 G71 N18 +12V G _054b N18 EGR valve N30 Injecor, cylinder 1 N31 Injecor, cylinder 2 N32 Injecor, cylinder 3 N33 Injecor, cylinder 4 N80 Acivaed charcoal filer sysem solenoid valve 1 N152 Igniion ransformer A B C Signal o self diagnosis faul warning lamp K83 (in models daing from 2000, his signal is ransferred via he CAN bus) Road speed signal from conrol uni wih display uni in dash panel inser J285 CAN bus S Fuse V60 Throle valve posiioner 39

40 Funcion diagram Example 3: 1.6-lr. perol engine 74 kw/siemens Simos 3 J17 +12V +12V S S S S S G188 G187 G186 J338 N156 N30 N31 N32 N33 +12V +5V J V +12V N152 J299 V101 G61 N80 G39 +12V 231_055a Componens G28 Engine speed sender G39 Lambda probe (before caalys) G40 Hall sender G61 Knock sensor I G62 Coolan emperaure sender G70 Air-mass flow meer G79 Acceleraor posiion sender G130 Lambda probe afer caalys G185 Acceleraor pedal posiion sender -2- G186 Throle valve drive G187 Throle valve drive angle sender -1- G188 Throle valve drive angle sender -2- G212 Exhaus gas recirculaion poeniomeer J17 Fuel pump relay J299 Secondary air pump relay J361 Simos conrol uni J338 Throle valve conrol uni 40

41 +12V N18 G212 G79 G185 A B C In fuure, lambda probes by NTK will also be fied in combinaion wih Simos engine conrol unis. +5V +5V +5V J361 Inpu signal Oupu signal Posiive Earh Daa line +5V N112 G130 G70 G62 G28 G40 +12V 231_055b N18 EGR valve N30 Injecor, cylinder 1 N31 Injecor, cylinder 2 N32 Injecor, cylinder 3 N33 Injecor, cylinder 4 N80 Acivaed charcoal filer sysem solenoid valve 1 N112 Secondary air inle valve N152 Igniion ransformer N156 Inake manifold change-over valve V101 A B C Secondary air pump Signal o self diagnosis faul warning lamp K83 (in models daing from 2000, his signal is ransferred via he CAN bus) Road speed signal from conrol uni wih display uni in dash panel inser J285 CAN bus S Fuse 41

42 Glossary Adapion Adap o changed condiions. D2, D3, D4 Exhaus emission sandards of he Federal Republic of Germany (refer o Self-Sudy Programme 230) NEFZ (Neuer Europäischer Fahrzyklus) New European driving cycle for deermining he exhaus emissions of moor vehicles 120 kph Elecrode Inerface beween an elecrical circui and a liquid or gaseous environmen (e.g. exhaus gas, ambien air) EOBD Euro On-Board Diagnosics EU II, EU III, EU IV Exhaus emission sandard of he European Union (refer o Self-Sudy Programme 230) sec. IWDS (Inegrierer Wellendichring-Sensor) Inegraed shaf sealing ring sensor Lambda (fuel-air raio, λ) Facor which describes he air concenraion in he fuel/air mixure. λ<1.0=rich mixure λ>1.0=lean mixure λ=1.0=heoreical opimal mixing raio Theoreically, λ is he air inflow rae o (heoreical) air demand raio: Air inflow rae / air demand = lambda λ Lambda conrol value The engine conrol uni calculaes he lambda conrol value from he lambda probe signals and engine operaing sae (e.g. engine speed, engine load). Based on his value, he fuel/air mixure is alered unil he opimum raio for he operaing sae is achieved. LSF Lambda probe fla (sep ype lambda probe) LSH Lambda probe heaing (finger probe) LSU Lambda probe universal (broadband lambda probe) Generic Scan Tool (OBD visual display uni) I mus be possible o read ou all emissionrelaed fauls which he EOBD has deeced via he diagnosis inerface wih any OBD visual display uni. The use of OBD visual display unis for spo checks is also planned. 42

43 Modulaion To change or adap he oscillaion frequency of a signal. Momen of force The momen of force (beer known as"orque") is he produc of an applied force and he associaed leverage. Momen of force = force x leverage Force Pump cell The pump cell comprises wo elecrodes separaed by a ceramic maerial permeable o oxygen. The oxygen ions O 2 (negaively charged) are conduced hrough he ceramic from he negaively charged elecrode (cahode) o he posiively charged elecrode (anode). The resul is he so-called "pump effec". Readiness code 8-characer number code which indicaes wheher he OBD diagnoses of he vehicle sysems were performed. "0" - performed "1" - no performed SAE code Faul code defined by he Sociey of Auomoive Engineers and binding for all OBD sysems. Leverage Example wih pison, connecing rod and crankshaf Wase gae (also known as "bypass") The wase gae passes excess exhaus gases by he urbocharger drive. This allows he urbocharger o be deacivaed or urbocharger power oupu o be reduced. Nerns cell (par he of lambda probe) The Nerns cell measures he differenial beween he oxygen concenraions in he ambien air and he exhaus gases and generaes a corresponding volage U. The Nerns cell comprises wo elecrodes, one on he ambien air side and and he oher on he exhaus side. OBD On-Board Diagnosics 43

44 Tes your knowledge 1. Unil when can buyers regiser new cars wihou EOBD if he new cars mee exhaus emission sandard D3? a) b) c) When does self diagnosis faul warning lamp K83 begin o flash? 3. Wha are he imporan poins o noe when replacing a broadband lambda probe (LSU)? a) The broadband lambda probe and he engine conrol uni are a sysem. Therefore, i is also necessary o replace he engine conrol uni. b) If he vehicle has wo lambda probes, boh probes mus be replaced. c) The broadband lambda probe and he engine conrol uni are a sysem and mus mach one anoher. d) The broadband lambda probe may only be replaced complee wih cable and connecors. 4. Wha is a Generic Scan Tool (OBD visual display uni) used for? a) The readiness code can be processed wih i. b) Emission-relaed daa, readiness codes, fauls, faul condiions and vehicle daa can be read ou wih i. In addiion, faul and readiness codes can be cancelled. c) Emission-relaed daa, readiness codes, fauls, faul condiions and vehicle daa can be read ou wih i. In addiion, faul and readiness codes can be canceled and shor rips can be performed. 44

45 Noes 45

46 Noes Soluions: 1. c 2. If he caalys can be damaged due o misfiring. 3. c, d 4. b 46

47 47

48 231 For inernal use only VOLKSWAGEN AG, Wolfsburg All righs reserved. Technical specificaions subjec o change wihou noice Technical saus: 05/00 This paper is produced from non-chlorine-bleached pulp.