Multiport Fuel Injection (mfi) - 3.0l Avk Audi A4 B6

Safety precautions

To reduce the risk of personal injury and/or damage to the fuel injection and ignition system, always observe the following

1. Always switch off ignition before disconnecting or connecting lines of the fuel injection and ignition system, including test leads.
2. If engine is to be cranked at starting RPM without starting (e.g. for compression testing), disconnect connector from ignition coils and from fuel injectors.
3. During some of the tests, a malfunction may be recognized and stored by the control module. At the end of all tests and repairs, the Diagnostic Trouble Code (DTC) memory should be checked and, if necessary, erased. After erasing the Diagnostic Trouble Code (DTC) memory the readiness code must be produced. See «READINESS CODE»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk__readiness-code) .
4. Always switch ignition off before cleaning engine.

If special testing equipment is required during road test, note the following

Rules for cleanliness

When working on the fuel supply/injection system, pay careful attention to the following 6 cleanliness rules

1. Thoroughly clean all unions and adjacent areas before disconnecting.
2. Place removed parts on a clean surface and cover. Use lint-free cloths.
3. Carefully cover or seal open components if repairs cannot be carried out immediately.
4. Install clean components: Remove replacement parts from packaging immediately prior to installation. Do not use parts that have been stored loose (e.g. in tool boxes etc.).
5. When the system is open: Do not work with compressed air if this can be avoided. Do not move vehicle unless absolutely necessary.
6. Separated electrical connectors: Protect from dirt and moisture. Make sure connections are dry when re-connecting.

Technical data

TECHNICAL DATA CHART

Component locations, overview

Note. The following list refers to (Scheme 264) and (Scheme 265).

1. Evaporative Emission (EVAP) canister purge regulator valve -N80- Checking. See «FUEL TANK BREATHER, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
2. Mass Air Flow (MAF) sensor -G70- With intake air temperature (IAT) sensor -G42- Checking. See «MASS AIR FLOW (MAF) SENSOR -G70-, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__mass-air-flow-maf-sensor-g70) .
3. Camshaft Position (CMP) sensor 3 -G300- For exhaust camshaft Cylinder bank 1 Checking. See «CAMSHAFT POSITION (CMP) SENSOR, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) .
4. Camshaft Position (CMP) sensor -G40- For intake camshaft Cylinder bank 1 Checking. See «CAMSHAFT POSITION (CMP) SENSOR, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) .
5. Pressure sensor for brake booster pressure sensor -G294- For vehicles with automatic transmission Location. See «LOCATION OF BRAKE BOOSTER PRESSURE SENSOR -G294»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
6. Camshaft Position (CMP) sensor -G163- For intake camshaft Cylinder bank 2 Checking. See «CAMSHAFT POSITION (CMP) SENSOR, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) .
7. Camshaft Position (CMP) sensor 4 -G301- For exhaust camshaft Cylinder bank 2 Checking. See «CAMSHAFT POSITION (CMP) SENSOR, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) .
8. Ignition coils with power output stage, bank 2 Ignition Coil 4 with Power Output Stage -N292- Ignition Coil 5 with Power Output Stage -N323- Ignition Coil 6 with Power Output Stage -N324- Checking. See «IGNITION COILS WITH OUTPUT STAGES, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) .
9. Electronics box (plenum chamber) Locations. See «LOCATION, ENGINE CONTROL MODULE IN ELECTRONICS BOX (PLENUM CHAMBER)»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) and «LOCATIONS IN ELECTRONICS BOX (PLENUM CHAMBER)»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__locations-in-electronics-box-plenum-chamber) . Location for Motronic Engine Control Module (ECM) -J220- Check power supply to engine control module. See «ENGINE CONTROL MODULE (ECM) POWER SUPPLY, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) . Procedure following interruption of voltage supply. See «PROCEDURE FOLLOWING INTERRUPTION OF VOLTAGE SUPPLY»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__procedure-following-interruption-of-voltage-supply) . Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) . Location for Motronic Engine Control module (ECM) power supply relay -J271- Test for Motronic Engine Control Module (ECM) power supply relay -J271-. See «MOTRONIC ENGINE CONTROL MODULE (ECM) POWER SUPPLY RELAY -J271-, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) . Location for Secondary Air Injection (AIR) pump relay -J299-. Check Secondary Air Injection (AIR) pump relay -J299-: See «SECONDARY AIR INJECTION (AIR) PUMP RELAY -J299- AND ACTIVATION, CHECKING»(/audi/a4/b6-2000-2006/remont/exhaust/#exhaust-system-emission-controls-30l-avk) Location for fuse S130 for secondary air pump Location for Brake booster relay -J569
10. Brake system vacuum pump -V192- For vehicles with automatic transmission
11. Valve 2 for camshaft adjustment -N208-, Camshaft adjustment valve 2 (exhaust) -N319- Cylinder bank 2 Checking: See «CAMSHAFT ADJUSTMENT, CHECKING»(ref-197058-S33337724442005101100000)
12. Fuel injectors, bank 2 Cylinder 4 Fuel Injector -N33- Cylinder 5 Fuel Injector -N83- Cylinder 6 Fuel Injector -N84- Checking. See «FUEL INJECTORS, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) Removing and installing. See «FUEL INJECTORS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
13. Fuel injectors, bank 1 Cylinder 1 Fuel Injector -N30- Cylinder 2 Fuel Injector -N31- Cylinder 3 Fuel Injector -N32- Checking. See «FUEL INJECTORS, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Removing and installing. See «FUEL INJECTORS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
14. Valve 1 for camshaft adjustment -N205- Camshaft adjustment valve 1 (exhaust) -N318- Cylinder bank 1 Checking: See «CAMSHAFT ADJUSTMENT, CHECKING»(ref-197058-S33337724442005101100000) .
15. Ignition coils with power output stage, bank 1 Ignition Coil 1 with Power Output Stage -N70- Ignition Coil 2 with Power Output Stage -N127- Ignition Coil 3 with Power Output Stage -N291- Checking. See «IGNITION COILS WITH OUTPUT STAGES, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) .
16. Secondary Air Injection (AIR) pump motor -V101- Checking: See «SECONDARY AIR INJECTION (AIR) PUMP MOTOR -V101-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/exhaust/#exhaust-system-emission-controls-30l-avk) .
17. Heated Oxygen Sensor (HO2S) -G39- and Oxygen sensor (O2S) heater -Z19- Bank 1, sensor 1 Constant Heated Oxygen Sensor (HO2S) Check oxygen sensors and oxygen sensor control before catalytic converter. See «OXYGEN SENSOR CONTROL, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Check aging of oxygen sensors before catalytic converter. See «OXYGEN SENSORS BEFORE CATALYTIC CONVERTER, CHECKING AGING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Check heating of oxygen sensors before catalytic converter. See «OXYGEN SENSORS BEFORE CATALYTIC CONVERTER, CHECKING HEATING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Removing and installing. See «OXYGEN SENSORS BEFORE CATALYTIC CONVERTER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
18. Bracket for connectors For right side of vehicle Assignment. See «IDENTIFICATION OF CONNECTOR BRACKET - RIGHT SIDE OF VEHICLE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-right) .
19. Oxygen sensor (O2S) behind three way catalytic converter (TWC) -G130- and Oxygen Sensor (O2S) heater 1 -Z29- Bank 1, sensor 2 Check oxygen sensors and oxygen sensor control behind catalytic converter. See «OXYGEN SENSORS AND OXYGEN SENSOR CONTROL BEHIND CATALYTIC CONVERTER, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__oxygen-sensors-and-oxygen-sensor-control) . Check heating of oxygen sensors behind catalytic converter. See «OXYGEN SENSORS BEHIND CATALYTIC CONVERTER, CHECKING HEATING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Removing and installing. See «OXYGEN SENSORS BEHIND CATALYTIC CONVERTER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
20. Engine Coolant Temperature (ECT) sensor -G62- For engine control module On coolant line behind cylinder head, bank 1 With Engine Coolant Temperature (ECT) sensor -G2- Checking. See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR -G62-, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) . If necessary, release cooling system pressure before removal
21. Throttle valve control module -J338- With Throttle drive (power accelerator actuation) -G186-, Angle sensor -1- for throttle drive (power accelerator actuation) -G187- and Angle sensor -2- for throttle drive (power accelerator actuation) -G188- Checking. See «THROTTLE VALVE CONTROL MODULE -J338-, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__throttle-valve-control-module-j338-checking) . Perform adaptation on replacing. See «THROTTLE VALVE CONTROL MODULE -J338-, ADAPTATION»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__throttle-valve-control-module-j338-adaptation) .
22. Secondary Air Injection (AIR) solenoid valve -N112- Checking: See «SECONDARY AIR INJECTION (AIR) SOLENOID VALVE -N112-, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/exhaust/#exhaust-system-emission-controls-30l-avk) .
23. Engine speed (RPM) sensor -G28- In gear case above ring gear Checking. See «ENGINE SPEED (RPM) SENSOR -G28-, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) .
24. Bracket for connectors For left side of vehicle Assignment. See «IDENTIFICATION OF CONNECTOR BRACKET - LEFT SIDE OF VEHICLE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-left) .
25. Throttle Position (TP) sensor -G79- and Sender -2- for accelerator pedal position -G185- Location. See «LOCATION OF THROTTLE POSITION (TP) SENSOR -G79- AND SENDER 2 FOR ACCELERATOR PEDAL POSITION -G185»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__location-of-throttle-position-tp-sensor) . Checking. See «ACCELERATOR POSITION SENSOR, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Adapting kick down function. See «KICKDOWN FUNCTION, ADAPTING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__kickdown-function-adapting) .
26. Fuel Pump (FP) relay -J17- Location. See «LOCATION OF FUEL PUMP (FP) RELAY -J17»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__location-of-fuel-pump-fp-relay) . Checking. See «FUEL PUMP (FP) RELAY -J17- AND ACTIVATION, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__fuel-pump-fp-relay-j17-and) .
27. Brake light switch -F- and Brake pedal switch (cruise control/diesel direct fuel injection -F47- Location. See «LOCATION BRAKE LIGHT SWITCH -F- AND BRAKE PEDAL SWITCH (CRUISE CONTROL/DIESEL DIRECT FUEL INJECTION -F47-, CLUTCH VACUUM VENT VALVE SWITCH -F36»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__location-brake-light-switch-f-and) . Checking. See «BRAKE LIGHT SWITCH AND BRAKE PEDAL SWITCH, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
28. Clutch vacuum vent valve switch -F36- Location. See «LOCATION BRAKE LIGHT SWITCH -F- AND BRAKE PEDAL SWITCH (CRUISE CONTROL/DIESEL DIRECT FUEL INJECTION -F47-, CLUTCH VACUUM VENT VALVE SWITCH -F36»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__location-brake-light-switch-f-and) . Checking. See «CLUTCH PEDAL SWITCH CHECK -F36-, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
29. Instrument cluster: With exhaust Malfunction Indicator Lamp (MIL) -K83-. Notes on warning lamp. See «EXHAUST MALFUNCTION INDICATOR LAMP (MIL) IN INSTRUMENT CLUSTER»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk__exhaust-malfunction-indicator-lamp-mil-in) . With Electronic Power Control (EPC) Warning Lamp -K132-. (check) Notes on EPC warning lamp. See «MALFUNCTION LAMP FOR ELECTRONIC THROTTLE IN INSTRUMENT CLUSTER»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__malfunction-lamp-for-electronic-throttle-in) .
30. Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) -G131- and Oxygen Sensor (O2S) heater 2 -Z30- Bank 2, sensor 2 Check aging of oxygen sensors behind catalytic converter. See «OXYGEN SENSORS BEHIND CATALYTIC CONVERTER, CHECKING AGING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Check heating of oxygen sensors behind catalytic converter. See «OXYGEN SENSORS BEHIND CATALYTIC CONVERTER, CHECKING HEATING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Removing and installing. See «OXYGEN SENSORS BEHIND CATALYTIC CONVERTER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
31. Heated oxygen sensor (HO2S) 2 -G108- and Oxygen Sensor (O2S) 2 heater -Z28- Bank 2, sensor 1 Constant heated oxygen sensor (HO2S) Check oxygen sensors and oxygen sensor control before catalytic converter. See «OXYGEN SENSOR CONTROL, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Check aging of oxygen sensors before catalytic converter. See «OXYGEN SENSORS BEFORE CATALYTIC CONVERTER, CHECKING AGING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Check heating of oxygen sensors before catalytic converter. See «OXYGEN SENSORS BEFORE CATALYTIC CONVERTER, CHECKING HEATING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Removing and installing. See «OXYGEN SENSORS BEFORE CATALYTIC CONVERTER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
32. Fuel pressure regulator Checking for vehicles up to 06.03. See «FUEL PRESSURE REGULATOR AND HOLDING PRESSURE (VEHICLES UP TO 06.03), CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__fuel-pressure-regulator-and-holding-pressure) . Integrated in fuel filter for vehicles as of 07.03 Checking for vehicles as of 07.03. See «SYSTEM PRESSURE AND HOLDING PRESSURE (VEHICLES AS OF 07.03), CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__system-pressure-and-holding-pressure-vehicles)
33. Knock Sensor (KS) 2 -G66- Bank 2 Under intake manifold
34. Intake manifold change-over valve -N156- Location. See «LOCATION OF INTAKE MANIFOLD CHANGE-OVER VALVE -N156»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__location-of-intake-manifold-change-over-valve) . Checking. See «INTAKE MANIFOLD CHANGE-OVER, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__intake-manifold-change-over-checking) .
35. Knock Sensor (KS) 1 -G61- Cylinder bank 1 Under intake manifold
36. Ground connection Right hand side engine support
37. Not installed

Location of Throttle Position (TP) sensor -G79- and Sender 2 for accelerator pedal position -G185

1. Incorporated in accelerator pedal module (arrow) NOTE: The Throttle Position (TP) sensor -G79- and Sender -2- for accelerator pedal position -G185- are incorporated in the accelerator pedal module and cannot be replaced separately.

Scheme 264

Removing and installing gas pedal module

See ACCELERATOR PEDAL MODULE WITH ACCELERATOR POSITION SENSOR, REMOVING AND INSTALLING .

Location of Fuel Pump (FP) relay -J17

1. On relay carrier in driver's footwell (left side), relay position 1 (arrow)

Location Brake light switch -F- and Brake pedal switch (cruise control/diesel direct fuel injection -F47-, Clutch vacuum vent valve switch -F36

1. Clutch Vacuum Vent Valve Switch -F36
2. Brake light switch -F-, Brake Pedal Switch (cruise control/Diesel Direct Fuel Injection -F47

Scheme 265

Removing and installing switches

See appropriate Clutches article in Transmission, and BRAKELIGHT SWITCH .

Scheme 266

Locations in electronics box (plenum chamber)

1. 1.1 - Coolant circulation pump relay -J151- (hot countries only)
2. 1.2 - Not used
3. 2 - Motronic Engine Control Module (ECM) power supply relay -J271
4. 3 - Secondary Air Injection (AIR) pump relay -J299- - Fuse S282 for engine electronics - Fuse S130 for secondary air pump - Not used

Scheme 267

Identification of connector bracket - right side of vehicle

Note. The following list refers to items in (Scheme 271).

1. 6-pin connector, black for Heated Oxygen Sensor (HO2S) -G39- and Oxygen Sensor (O2S) heater -Z19- (bank 1, sensor 1)
2. 3-pin connector, blue for Knock Sensor (KS) 1 -G61
3. 4-pin connector, green for Oxygen Sensor (O2S) 2 behind three way catalytic converter (TWC) -G130- and Oxygen Sensor (O2S) heater 1 -Z29- (bank 1, sensor 2)
4. 3-pin connector, black for terminal 50

Identification of connector bracket - left side of vehicle

1. 4-pin connector, brown for Oxygen Sensor (O2S) 2 behind three way catalytic converter (TWC) -G131- and Oxygen Sensor (O2S) heater 2 -Z30- (bank 2, sensor 2)
2. 3-pin connector, gray for Engine speed (RPM) sensor -G28
3. 3-pin connector, blue for Knock Sensor (KS) 2 -G66
4. 6-pin connector, black for Heated Oxygen Sensor (HO2S) 2 -G108- and Oxygen Sensor (O2S) 2 heater -Z28- (bank 1, sensor 1)

Note. To gain access to the harness connectors, you must remove the cover on left side of engine compartment, disconnect cable to coolant shortage indicator switch at bottom of expansion tank, remove screw for coolant expansion tank (arrow) and lay aside. Coolant hoses -1 to 3- do not have to be disconnected.

Scheme 268

Scheme 269

Location of Intake manifold change-over valve -N156

1. Clipped to vacuum module

Air cleaner, disassembling and assembling

Note. The following list refers to (Scheme 276).

1. To/from Secondary Air Injection (AIR) pump motor -V101
2. O-ring Always replace
3. Self-tapping screw
4. Air duct
5. Air duct To lock carrier
6. Spreader clip
7. Seal
8. Cover
9. Mass Air Flow (MAF) sensor -G70
10. Connecting hose
11. Self-tapping screw
12. Air cleaner housing, upper part
13. Filter element
14. Air cleaner housing, lower part

Intake manifold change-over system components, removing and installing

Note. The following list refers to (Scheme 277).

1. Intake manifold change-over valve -N156
2. Y-piece
3. Self-tapping screw
4. Vacuum actuator
5. Seals For change-over mechanism Replace, if damaged
6. Spring
7. Change-over mechanism
8. Mounting plate
9. Rubber grommet
10. Spacer sleeve
11. 10 N.m
12. Secondary Air Injection (AIR) solenoid valve -N112
13. Non-return valve Installation position: Blue side facing Y-piece
14. To secondary air inlet combi valves
15. Y-piece
16. To vacuum reservoir
17. T-piece
18. Intake manifold

Wiring and component check with test box VAG 1598/31

Note. The test box VAG1598/31 is designed in such a way to be connected simultaneously to the engine control module wiring harness and to the engine control module. This has the advantage that the electronic motor control system remains fully functional when the test box is connected (for example, for measuring signals when the engine is running). Whether the engine control module has to be connected to the test box or not is described in the respective test procedures.

1. Switch ignition off.
2. Remove engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .
3. Connect VAG1598/31 test box to connectors of wiring harness. Connect Ground clamp on test box (not shown in illustration) to vehicle Ground. Whether or not engine control module has to be connected to test box is described in respective test procedures.

Note. After reinstalling the engine control module the following operations must be performed: Checking of Diagnostic Trouble Code (DTC) memory and erase, if necessary. See DIAGNOSTIC TROUBLE CODE (DTC) MEMORY . If DTC memory has been erased, readiness code must be regenerated. See READINESS CODE, GENERATING .

Procedure following interruption of voltage supply

Note. After reconnecting the voltage supply the following operations must be performed: Checking of Diagnostic Trouble Code (DTC) memory and erase, if necessary. See DIAGNOSTIC TROUBLE CODE (DTC) MEMORY . If DTC memory has been erased, readiness code must be regenerated. See READINESS CODE, GENERATING .

The following steps need to be performed after reconnecting the power supply

1. Activate engine control module via "Guided fault finding" function (diagnosis object "Replacing engine control module").

For this step use vehicle diagnostic, testing and information system VAS5051.

Engine Control Module (ECM) (without metal anti-theft housing), replacing

Removing ECMs with metal anti-theft housing. See ENGINE CONTROL MODULE (ECM) (WITH METAL ANTI-THEFT HOUSING), REPLACING .

Removing

1. Connect vehicle diagnostic, test and information system VAS5051 and select vehicle system "01 - Engine electronics". Ignition must be on. The display on vehicle diagnostic, test and information system VAS5051 will show the control module identification and the coding -2-.
2. Always start by calling up and printing out control module identification.
3. Switch off ignition.
4. Pull off rubber seal of plenum chamber cover.
5. Remove plenum chamber cover -1- toward front (arrows).
6. Pry off cover caps -3- (2x) with a screwdriver.
7. Loosen hex nuts -4- several turns.
8. Disengage wiper arms -2- from their shafts by lifting them gently.
9. Remove hex nuts completely and take off wiper arms.
10. Pull off securing clips -1- and remove scuttle panel grille -5-.
11. Remove cover for electronics box in plenum chamber (arrows).
12. Pry off retainer bar with a screwdriver (arrows).
13. Release retainer catches (arrows) and disconnect connectors -1- and -2- from engine control module.
14. Take out engine control module.

Installing

Install in reverse sequence; note the following points

The following steps need to be performed after connecting the new engine control module

1. Activate engine control module via "Guided fault finding" function (diagnosis object "Replacing engine control module").

For this step use vehicle diagnostic, testing and information system VAS5051.

Engine Control Module (ECM) (with metal anti-theft housing), replacing

Removing ECMs without metal anti-theft housing. See ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING .

1. Connect VAS5051 tester and select vehicle system "01 - Engine Electronics". Ignition must be switched on for this. VAS5051 tester display will indicate the control module identification and coding -2-.
2. Always allow display of control module identification first and print it out.
3. Switch ignition off.
4. Pull off plenum chamber cover rubber seal in direction of arrow.
5. Remove cover -1- toward front.
6. Pry off both covers -3- using a screwdriver.
7. Loosen hex-nuts -4- several turns.
8. Loosen wiper arm -2- by lightly tilting from wiper axle.
9. Remove hex nuts completely and remove wiper arms.
10. Disconnect securing clips -1- and remove cowl grill -5-.
11. Remove cover for E-box, plenum chamber (arrows).
12. Using a screwdriver, carefully pry off retaining bracket (arrow). NOTE: Item -1- in illustration shows Engine Control Module (ECM) with antitheft housing.

To restrict accessibility (for theft prevention) to the harness connectors and the Engine Control Module (ECM), the ECM -1- is screwed to a metal anti-theft housing -4- via a locking mechanism -2- and snap-off screws -3-.

Scheme 270

The threads of the snap-off screws are coated with a locking compound to make it more difficult to remove the snap-off screws.

To disconnect the harness connectors from the Engine Control Module (ECM) (e.g. when connecting a test box or when replacing the ECM), the ECM must be removed from the metal anti-theft housing. This procedure is described as follows.

The following equipment is required

1. Heat gun -1- (from VAS1978 Wiring Harness Repair Kit)
2. Adapter nozzle -2- (also from VAS1978 Wiring Harness Repair Kit)
3. Standard locking pliers

Procedure

Scheme 271

Scheme 272

1. "Fold" Engine Control Module (ECM) with anti-theft housing in direction of engine compartment so that locking mechanism (item -2- in illustration) becomes visible and place a clean rag below Engine Control Module (ECM) with anti-theft housing.
2. Adjust heat gun as shown in illustration, i.e. temperature adjustment -2- to maximum heat output and two-stage switch for air mass -3- to position 3. NOTE: Next, use a heat gun to heat the threads of the locking mechanism into which the snap-off screws are screwed into. This step loosens the locking compound on the threads of the snap-off screws for easier removal. WARNING: By heating the locking mechanism threads, the snap-off screws and parts of the metal anti-theft housing will also become very hot. Be careful not to get burned! If possible, make sure that the threads and no other parts in the vicinity become heated. If necessary, cover them.
3. Guide nozzle -1- of heat gun to locking mechanism threads so that nozzle "encloses" threads. It is OK to let nozzle make contact at upper end of metal anti-theft housing.
4. Switch on heat gun and heat up threads for approx. 20 to 25 seconds.
5. Next, using locking pliers -1-, grab screw head -2- and remove snap-off screw by turning in direction of arrow. Procedure for the second snap-off screw is exactly the same. Be very careful since the control module connector is in close proximity.
6. Guide nozzle -1- of heat gun to locking mechanism threads again so that nozzle "encloses" threads. It is OK to let nozzle make contact at upper end of metal anti-theft housing.
7. Switch on heat gun and heat up threads for approx. 20 to 25 seconds.
8. Next, using locking pliers -1-, grab screw head -2- and remove snap-off screw by turning in direction of arrow. The Engine Control Module (ECM) can now be removed from the metal anti-theft housing.
9. Disengage connectors from Engine Control Module (ECM) and disconnect connectors.
10. Remove old Engine Control Module (ECM) and insert new one.

Installing Engine Control Module (ECM)

Installation is reverse of removal, noting the following

After repairs are complete, the metal anti-theft housing must be reinstalled. Use new snap-off screws.

After connecting a new Engine Control Module (ECM), the following work steps must be performed

1. Activate Engine Control Module (ECM) in "Guided Troubleshooting" below subject heading "Engine Control Module (ECM), replacing".

Use VAS5051 tester to do so.

Special tools and equipment

1. VAS5051 with VAS5051/1

Test requirements

1. No leaks in exhaust system
2. Engine coolant temperature at least 80 °C.
3. Electrical accessories switched off (coolant fan must not run during the test).
4. Air conditioning switched off.
5. Pressure gauge not connected.
6. Vehicles with automatic transmission: Selector lever in position P or N.

Note. The idling speed is tested during the basic setting of the engine. During basic setting, the solenoid valve for the evaporative emission (EVAP) canister purge regulator valve -N80- is closed and the air conditioner compressor is switched off. To eliminate vibration noises in case of a customer complaint, the idling speed can be adapted. See ADAPTATION .

Test sequence

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01 - Engine electronics" in selection. Engine must be running at idling speed.
2. Check Diagnostic Trouble Code (DTC) memory. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . There must not be any DTCs stored. If necessary, correct any DTCs and erase DTC memory. After erasing DTC memory readiness code must be regenerated. See «READINESS CODE, GENERATING»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) .
3. Leave engine idling. CAUTION: The coolant fan should not be running.

Display on VAS5051

Scheme 273

1. Under -1- select diagnostic function "04 - Basic setting".

Display on VAS5051

Scheme 274

1. Enter display group max. input value = 255 Enter "056" for "display group number 056" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 275

1. Activate basic setting by pressing -A- button.
2. Check whether engine speed in display zone -1- (actual speed) is within permitted tolerance range.

All models

DISPLAY GROUP 056: IDLING SPEED STABILIZATION AT OPERATING TEMPERATURE

Note. The engine speed in display zone 1 (actual speed) is the actual engine speed. The engine speed in display zone 2 (specified speed) is a theoretical value calculated by the engine control module. During idling, the engine control module always tries to adapt the actual engine speed to the specified engine speed. This means that during idling the actual engine speed must always be approximate to the specified engine speed. Display zones 3 and 4 are there for information but are irrelevant to the control of the engine idling speed.

1. Exit function "04 - Basic setting" by pressing [left arrow] button. If specified value is not obtained
2. Check Diagnostic Trouble Code (DTC) memory again. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) .
3. If DTC memory was erased, readiness code must be re-generated. See «READINESS CODE, GENERATING»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) .

If the idling speed is too high or too low and there are no DTCs recorded in the DTC memory, perform the following tests marked with a dot

1. Check intake air system for unmetered air. See «INTAKE AIR SYSTEM FOR LEAKS (UNMETERED AIR), CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
2. Check throttle valve control module. See «THROTTLE VALVE CONTROL MODULE -J338-, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__throttle-valve-control-module-j338-checking) .
3. Check whether solenoid valve for Evaporative Emission (EVAP) canister purge regulator valve is continuously open. See «EVAPORATIVE EMISSION (EVAP) CANISTER PURGE REGULATOR VALVE -N80-, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
4. Perform adaptation of throttle valve control module. See «THROTTLE VALVE CONTROL MODULE -J338-, ADAPTATION»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__throttle-valve-control-module-j338-adaptation) .

Significance of 5-digit readout of display group 056

SIGNIFICANCE OF 5-DIGIT READOUT OF DISPLAY GROUP 056 CHART

Fuel pressure regulator and holding pressure (vehicles up to 06.03), checking

Note. The fuel pressure regulator regulates the fuel pressure according to the intake manifold pressure. The pressure drop at the injectors remains constant for each engine speed and load range.

1. VAG1318 with VAG1318/6 and VAG1318/7

1. Fuel pump relay OK; checking. See «FUEL PUMP (FP) RELAY -J17- AND ACTIVATION, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__fuel-pump-fp-relay-j17-and) .
2. Fuel pump OK; checking: See «FUEL SUPPLY»(/audi/a4/b6-2000-2006/remont/fuel-system/#fuel-supply) .
3. Fuel filter OK
4. Battery voltage at least 12.7 V
5. Vehicles with automatic transmission: Selector lever in position P or N.

1. Remove rear engine cover (arrows).

Checking system pressure

1. Briefly open fuel tank filler cap (to release pressure).
2. Connect pressure gauge VAG1318 to fuel supply line using adapters 1318/6 and 1318/7.
3. Disconnect vacuum hose from pressure regulator to intake manifold at pressure regulator and close off hose. NOTE: If fuel flows at the vacuum connection on the pressure regulator during the following pressure test, replace pressure regulator.
4. Start engine and run at idling speed.
5. Measure fuel pressure. Specified value: 3.8 to 4.2 bar
6. If fuel pressure does not match specification, install a new fuel pressure regulator and repeat pressure test.
7. If fuel pressure still does not match specification, check fuel pump and supply line for damage (e.g. crushing) and replace if necessary.
8. If pressure is higher than specification, check return line for damage (e.g. crushing) and replace, if necessary.

Note. During the following test, do not leave the engine running too long with the vacuum hose disconnected, because the higher fuel pressure causes the fuel and air mixture to be rich. This could lead to the Oxygen sensor control limits to be exceeded. This would result in a DTC being recorded.

1. Start engine and run at idling speed.
2. Switch off electrical accessories (air conditioner, etc.).
3. Re-connect vacuum hose to pressure regulator and observe drop in pressure on pressure gauge.
4. Fuel pressure must be lowered by approx. 0.5 bar when vacuum hose is attached. Perform the following checks if there is no change in pressure as described above: Check vacuum hose for cracks and damage. Test vacuum hose for blockage at intake manifold. To do this, disconnect hose at fuel pressure regulator and blow into it.
5. If there is no leak and no blockage in vacuum hose, install a new fuel pressure regulator.

Testing holding pressure

1. Holding pressure 10 minutes after switching off engine (minimum pressure). Specified value for cold engine: approx. 2.2 bar Specified value with engine at operating temperature: approx. 3.0 bar

Note. The increase in temperature with the engine at operating temperature is caused by the expansion of the fuel is normal.

1. Start engine and run at idling speed.
2. Allow pressure to build up, then switch off ignition. At same time close cut off valve on pressure gauge VAG1318 (valve lever at right angles to direction of flow (arrow)).
3. Observe pressure drop on pressure gauge.

If the pressure does not drop, the following DTCs are possible

1. Union between pressure gauge and fuel supply line leaking
2. Supply line leaking at fuel tank
3. Non-return valve in fuel pump leaking See «FUEL SUPPLY»(/audi/a4/b6-2000-2006/remont/fuel-system/#fuel-supply) .

Note. When the shut off valve is closed the pressure gauge shows the pressure after the isolating valve "intake manifold end" (direction of injectors, fuel pressure regulator). If the pressure before the isolating valve (tank direction) should now fall, the equipment cannot recognize this.

If the pressure drops again, the following DTCs are possible

1. Fuel pressure regulator malfunction
2. Injectors leaking
3. Unions on pressure gauge after cut-off valve leaking NOTE: When disconnecting the pressure gauge, close the shut-off valve, unscrew the union on adapter VAG1318/15, then open the shut-off valve to drain off excess fuel into a suitable container.

System pressure and holding pressure (vehicles as of 07.03), checking

Note. Fuel pressure regulator is integrated in fuel filter (under fuel tank) and cannot be replaced individually.

Recommended special tools and equipment

1. Fuel Inj. Pressure Gauge-CIS V.A.G 1318 with adapters V.A.G 1318/6 and V.A.G 1318/7

1. Fuel Pump (FP) Relay OK; checking. See «FUEL PUMP (FP) RELAY -J17- AND ACTIVATION, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__fuel-pump-fp-relay-j17-and) .
2. Delivery quantity of transfer Fuel Pump (FP) OK See «FUEL SUPPLY»(/audi/a4/b6-2000-2006/remont/fuel-system/#fuel-supply) .
3. Fuel filter OK
4. Vehicles with automatic transmission: Selector lever in position "P" or "N".
5. Battery voltage at least 12.7 V

1. Remove rear engine cover (arrows).

1. Open fuel filler cap briefly (pressure release). WARNING: Fuel system is under pressure! Before opening system, place rags around the connection. Then release pressure by carefully loosening connection.
2. Unscrew fuel hose from connection on fuel rail pipe. To do so, counterhold using an open-end wrench at each hex head -1- and -3- and unscrew union nut -2-.
3. Connect V.A.G 1318 Fuel Inj. Pressure Gauge-CIS in supply line using adapters 1318/6 and 1318/7.
4. Open shut-off valve of pressure gauge. The lever points in the direction of flow.
5. Start engine and let run at idle.
6. Measure fuel pressure. Specified value: 3.8 to 4.2 bar
7. Switch ignition off.

Checking holding pressure

1. Check for proper seal and residual pressure by observing pressure drop on pressure gauge. Specified value with a cold engine: approx. 2.2 bar Specified value with the engine at operating temperature: approx. 3.0 bar

Note. Pressure increase for an engine at operating temperature due to fuel expansion is normal.

If holding pressure sinks below 2.2 / 3.0 bar positive pressure

1. Start engine and let run at idle.
2. Wait until pressure has built up, and then switch off ignition. Simultaneously close shut-off valve of V.A.G 1318 Fuel Inj. Pressure Gauge-CIS (lever perpendicular to direction of flow -arrow-).
3. Observe pressure drop on pressure gauge.

If pressure drops again

1. Check pressure gauge for proper seal.
2. Check line connections and fuel injectors for proper seal.

If pressure does not drop now

1. Check pressure regulator in fuel filter: Vehicles with Front Wheel Drive (FWD). See «CHECKING FUEL PRESSURE REGULATOR - VEHICLES WITH FRONT WHEEL DRIVE (FWD)»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__checking-fuel-pressure-regulator-vehicles) . Vehicles with All Wheel Drive (AWD). See «CHECKING FUEL PRESSURE REGULATOR - VEHICLES WITH ALL WHEEL DRIVE (AWD)»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__checking-fuel-pressure-regulator-vehicles) .

Checking fuel pressure regulator - vehicles with Front Wheel Drive (FWD)

Sedan

1. Remove luggage compartment lining.
2. Push forward the right backrest of rear seat, if necessary.

Station wagon

1. Remove left 1/3 backrest. See «LEFT 1/3 BACKREST, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/seats/#seats-frames-except-cabriolet) .
2. Remove left side trim in luggage compartment and dirt tray. For Cabriolet models, see «LUGGAGE COMPARTMENT TRIM»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-cabriolet) . For all models except Cabriolet, see «LUGGAGE COMPARTMENT SIDE TRIM, ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet__luggage-compartment-side-trim-assembly-overview) (Sedan), or «SIDE LUGGAGE COMPARTMENT TRIM, ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/gauges-instrument-panels/#interior-trim-except-cabriolet__side-luggage-compartment-trim-assembly-overview) (Avant wagon).

All

1. Remove cover for connector flange (arrows).
2. Disconnect fuel return line (arrow) (press release button).
3. Connect V.A.G 1318/17-1 adapter piece to return line.
4. Pinch off adapter piece using 3094 hose clamps up to 25 mm dia. NOTE: 3094 hose clamps up to 25 mm dia. must not be placed directly on fuel line, otherwise it may be damaged.
5. Start engine and let run at idle.
6. Wait until pressure has built-up, and then switch off ignition. Simultaneously close shut-off valve of V.A.G 1318 Fuel Inj. Pressure Gauge-CIS (lever perpendicular to direction of flow -arrow-).
7. Observe pressure drop on pressure gauge.

If pressure drops again, check-valve of fuel pump is leaky.

1. Replace Fuel Pump (FP). See «FUEL SUPPLY»(/audi/a4/b6-2000-2006/remont/fuel-system/#fuel-supply) .

If pressure does not drop now

1. Replace fuel filter with integrated fuel pressure regulator.

Assembly is performed in the reverse order of removal, noting the following

Note. Before disconnecting pressure gauge, release pressure by opening shut-off valve. Hold a container in front of connection for this.

1. Secure fuel hose to connection on fuel rail pipe. To do so, counterhold using an open-end wrench at each hex head -1- and -3- and tighten union nut -2- to 22 N.m.

Checking fuel pressure regulator - vehicles with All Wheel Drive (AWD)

1. Remove rear seat bench. For Cabriolet models, see «REAR SEAT BENCH, ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/seats/#seats-frames-cabriolet__rear-seat-bench-assembly-overview) . See models other than Cabriolet, see «SEATBENCH, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/seats/#seats-frames-except-cabriolet__seatbench-removing-and-installing) .
2. Remove cover for left connector flange (arrows).
3. Disconnect fuel return line (arrow) from connector flange (left side of vehicle).
4. Connect V.A.G 1318/17-1 adapter piece to return line.
5. Pinch off adapter piece using 3094 hose clamps up to 25 mm dia. NOTE: 3094 hose clamps up to 25 mm dia. must not be placed directly on fuel line, otherwise it may be damaged.
6. Start engine and let run at idle.
7. Wait until pressure has built-up, and then switch off ignition. Simultaneously close shut-off valve of V.A.G 1318 Fuel Inj. Pressure Gauge-CIS (lever perpendicular to direction of flow -arrow-).
8. Observe pressure drop on pressure gauge. If pressure drops again, check-valve of fuel pump is leaky.

1. Replace Fuel Pump (FP). See «FUEL SUPPLY»(/audi/a4/b6-2000-2006/remont/fuel-system/#fuel-supply) .

If pressure does not drop now

1. Replace fuel filter with integrated fuel pressure regulator.

Assembly is performed in the reverse order of removal, noting the following

Note. Before disconnecting pressure gauge, release pressure by opening shut-off valve. Hold a container in front of connection for this.

1. Secure fuel hose to connection on fuel rail pipe. To do so, counterhold using an open-end wrench at each hex head -1- and -3- and tighten union nut -2- to 22 N.m.

1. VAG1526 A
2. VAG1527 B
3. VAG1594 A
4. VAG1598/31

Scheme 276

1. Remove front engine cover (arrows).
2. Disconnect connectors to Intake manifold change-over valve -N156- -1-.

Both cylinder banks, continued

1. Disconnect all connectors for injectors of relevant cylinder bank, release connectors underneath for this purpose (arrow).

Scheme 277

1. Connect multimeter to injector to measure resistance. Specified value: 11 to 13 ohms (at room temperature) When the engine is at operating temperature the resistance is increased by approx. 4 to 6 ohms.

If specified value is not obtained

1. Replace injector. See «FUEL INJECTORS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .

If specified value is obtained

1. Fuse for injectors OK
2. Fuel pump relay OK. Checking. See «FUEL PUMP (FP) RELAY -J17- AND ACTIVATION, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__fuel-pump-fp-relay-j17-and) .

Note. The injectors receive their power supply via the fuel pump relay.

Scheme 278

1. Connect voltage tester VAG1527 B as follows: FUEL INJECTOR HARNESS CONNECTOR TERMINAL 1 VOLTAGE REFERENCE Connector terminal Measure to 1 Engine ground
2. Switch ignition on. LED should illuminate.

If the LED does not illuminate

1. Check wiring connection between terminal 1 and fuse for injector for open circuit: See appropriate System Wiring Diagram article.
2. Repair open circuit, if necessary.

If the LED illuminates

1. Internal resistance of the valve OK

1. Connect voltage tester VAG1527 B with measuring probes and plug-in adapters from VAG1594 A between terminal 2 (signal) and terminal 1 (positive); connector remains plugged in.
2. Operate starter briefly (engine may start). LED should flash. NOTE: Voltage testers with a low current draw continue to glow faintly between actuation from the engine control module (rather than extinguishing completely) and become slightly brighter when actuated.

If LED does not flash

Scheme 279

1. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit and short to positive or Ground in following wiring connections in «FUEL INJECTOR CIRUIT IDENTIFICATION»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) table: FUEL INJECTOR CIRUIT IDENTIFICATION Cylinder Injector connector terminal : Test box VAG 1598/31 Socket 1 2 96 2 2 112 3 2 88 4 2 97 5 2 113 6 2 89
3. Repair any open/short circuit as necessary.

If no wiring malfunction is detected

1. Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .

Fuel rail with injectors, disassembling and assembling

Note. The following list refers to (Scheme 331).

1. Retaining clip Make sure clip is positioned correctly at injector and fuel rail
2. O-ring Removing and installing. See «FUEL INJECTORS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Always replace Coat with clean engine oil.
3. Injector Removing and installing. See «FUEL INJECTORS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
4. O-ring Removing and installing. See «FUEL INJECTORS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Always replace Coat with clean engine oil.
5. Fuel return line Only in vehicles up to 06.03
6. Fuel supply line For vehicles up to 06.03, tighten union nut to 22 N.m Loosening and tightening union in vehicles as of 07.03. See «LOOSENING AND TIGHTENING UNION NUT FOR FUEL SUPPLY LINE IN VEHICLES AS OF 07.03»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__loosening-and-tightening-union-nut-for) . WARNING: Fuel system is under pressure! Before opening system, place rags around the connection. Then release pressure by carefully loosening connection.
7. 10 N.m
8. Fuel rail
9. 10 N.m
10. Retaining clip Make sure tight fit
11. O-rings Always replace Moisten with clean engine oil.
12. Fuel pressure regulator Integrated in fuel filter in vehicles as of 07.03
13. Vacuum hose

Loosening and tightening union nut for fuel supply line in vehicles as of 07.03

Loosening

1. Unscrew fuel hose from connection on fuel rail pipe. To do so, counterhold using an open-end wrench at each hex head -1- and -3- and unscrew union nut -2-.

Tightening

1. Secure fuel hose to connection on fuel rail pipe. To do so, counterhold using an open-end wrench at each hex head -1- and -3- and tighten union nut -2- to 22 N.m.

Scheme 280

1. Disconnect battery Ground cable.
2. Remove rear engine cover (arrows).
3. Disconnect check valve hose.
4. Remove bolts for retainer plate for solenoid valve (arrows).
5. Lift up retainer plate and move it toward rear of engine.
6. Remove front engine cover (arrows).
7. Disconnect harness connectors to Intake manifold change-over valve -N156- -1-.
8. Gently lift up fuel rail and disconnect all harness connectors at fuel injectors. Disengage harness connectors underneath (arrow).

Vehicles up to 06.03

1. Disconnect vacuum hose -3- from fuel pressure regulator. NOTE: To install a new fuel rail disconnect the fuel supply line -2- and return line -1-. WARNING: The fuel system is under pressure! Place a cloth around the connection point before opening the system. Then open the connection carefully to relieve pressure.

All

1. Unbolt fuel rail from intake manifold (arrows).

Vehicles as of 07.03

To replace the fuel rail pipe, fuel hose must be unscrewed from connection on fuel rail pipe. To do so, counterhold using an opened wrench at each hex head -1- and -3- and unscrew union nut -2- (tightening torque 22 N.m).

Scheme 281

1. Remove fuel rail together with injectors from intake manifold and place it on a clean cloth at back of engine compartment.
2. Remove retaining clip and remove injector.

Install in reverse order, note the following

1. Replace the O-rings at all opened connections.
2. Coat the O-rings with clean engine oil.
3. Make sure that the injectors are installed in the correct positions.
4. Check to make sure that the retainer clamps are properly seated.
5. Position fuel rail with injectors on intake manifold and press evenly into place.

Tightening torque

TIGHTENING TORQUE (FUEL INJECTORS)

1. VAG1348/3A with 1348/3-2
2. VAG1594 A
3. VAG1598/31
4. VAG1602

1. Fuel pressure OK, checking. See «FUEL PRESSURE REGULATOR AND HOLDING PRESSURE (VEHICLES UP TO 06.03), CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__fuel-pressure-regulator-and-holding-pressure) .

1. Remove fuel rail with injectors installed from intake manifold. See «FUEL INJECTORS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Do not disconnect fuel hoses.
2. Connect test box VAG1598/31 to wiring harness for engine control module. Do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .

Testing for leaks

1. Bridge terminals 1 and 65 at test box using test leads adapter kit VAG1594A.
2. Switch ignition on. Fuel pump should run.
3. Check injectors for leaks (visual check). When fuel pump is running, only 1 or 2 drops a minute should escape from each injector.
4. If a greater amount of fuel escapes, switch off fuel pump (disconnect cable bridge) and replace faulty injector. See «FUEL INJECTORS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk)

Checking injection quantity

1. Place injector which is to be tested in a measuring glass from injection quantity tester VAG1602.
2. Connect one injector terminal to engine Ground using a test lead and alligator clip from VAG1594 A.
3. Connect second injector terminal to positive using remote control VAG1348/3A, adapter lead VAG1348/3-2 and auxiliary cable.
4. Bridge terminals 1 and 65 at test box using leads from adapter kit VAG1594 A.
5. Switch ignition on. The fuel pump should run.
6. Activate remote control VAG1348/3 A for 30 seconds.
7. When all three injectors of a cylinder bank have been activated, place three measuring glasses on a flat surface. Specification per injector: 90 to 125 ml
8. If measured values for one or more injectors are outside tolerance range, stop fuel pump (switch off ignition) and replace faulty injector. See «FUEL INJECTORS, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
9. Repeat test on injectors from second bank of cylinders.
10. If measured values for all injectors are outside tolerance range, check fuel pressure. See «FUEL PRESSURE REGULATOR AND HOLDING PRESSURE (VEHICLES UP TO 06.03), CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__fuel-pressure-regulator-and-holding-pressure) . NOTE: When checking the injection quantity, also check the spray pattern. The spray pattern should be the same for all the injectors.
11. Install injectors with fuel rail. See «INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .

Fuel Pump (FP) relay -J17- and activation, checking

Special tools and equipment

1. VAG1526 A
2. VAG1594 A
3. VAG1598/31
4. VAS5051 with VAS5051/1

The fuel pump and certain components of the injection system are supplied with power by way of the Fuel Pump (FP) relay -J17-.

The Fuel Pump (FP) relay -J17- is only energized when the engine is running, i.e. the relay is only connected to Ground (via the engine control module) when engine speed pulses are detected in the engine control module.

1. Battery voltage at least 12.7 V

Functional check of fuel pump relay

1. Remove driver's storage compartment: For Cabriolet models, see «DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW»(ref-197209-S29048734852005101300000) . For models other than Cabriolet, see «DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__driver-side-storage-compartment-with-and-without) .
2. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01 Engine electronics" in selection. Ignition must be switched on.
3. Initiate final control diagnosis. See «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk__output-diagnostic-test-mode-dtm) . Actuate Evaporative Emission (EVAP) canister purge regulator valve -N80-.

1. Fuel pump relay (on the 9-unit-relay carrier in the driver's footwell on the left, position 1) should pull and fuel pump should run.

1. If relay does not respond: Check voltage supply of fuel pump relay. See «CHECKING VOLTAGE SUPPLY OF FUEL PUMP RELAY»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Check activation of fuel pump relay. See «CHECKING ACTIVATION OF FUEL PUMP RELAY»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__checking-activation-of-fuel-pump-relay) .
2. If relay is energized but fuel pump does not run: Check voltage supply for fuel pump and components (via fuel pump relay). See «CHECKING VOLTAGE SUPPLY OF FUEL PUMP AND COMPONENTS»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__checking-voltage-supply-of-fuel-pump) .

Scheme 282

1. Disconnect fuel pump relay.
2. Connect multimeter as follows to measure voltage. TERMINAL 1 VOLTAGE REFERENCE (FUEL PUMP RELAY CHECKING) 9-unit relay carrier in driver's footwell on left, position 1 terminal Measure to 1 Car body ground point Specified value: approx. battery voltage
3. Connect multimeter as follows to measure voltage: TERMINAL 3 VOLTAGE REFERENCE (FUEL PUMP RELAY CHECKING) 9-unit relay carrier in driver's footwell on left, position 1 terminal Measure to 3 Car body ground point
4. Switch ignition on. Specified value: approx. battery voltage

If the specified values are not obtained

1. Check wiring connections. See appropriate System Wiring Diagram article.

If specifications are obtained

Checking activation of fuel pump relay

1. Switch ignition off.
2. Reconnect relay.
3. Connect test box VAG1598/31 to wiring harness or engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
4. Bridge terminals 1 and 65 at test box with leads from adapter kit VAG1594A.
5. Switch ignition on. Fuel pump relay (on the 9-unit-relay carrier in the driver's footwell on the left, position 1) should pull and fuel pump should run.

If the relay responds now, but not during final control diagnosis

1. Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .

If the relay does not respond

Scheme 283

1. Switch ignition off.
2. Disconnect cable link.
3. Disconnect fuel pump relay.
4. Check for open circuit and short to positive or Ground in following wiring connection: TERMINAL 5 WIRING CONNECTION REFERENCE (FUEL PUMP RELAY CHECKING) 9-unit relay carrier in driver's footwell on left, position 1 terminal Test box VAG1598/31 Socket 5 65
5. Repair any open/short circuit as necessary.

If no DTC is found

1. Replace Fuel Pump (FP) relay -J17-.
2. Reconnect engine control module.

Checking voltage supply of fuel pump and components

1. Disconnect fuses S228, S229 and S234 (positions 28, 32 and 34) in fuse holder.
2. Initiate final control diagnosis. See «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk__output-diagnostic-test-mode-dtm) . Actuate evaporative emission (EVAP) canister purge regulator valve -N80-.
3. To measure voltage, connect multimeter to Ground and to one terminal of following fuses in fuse holder. SPECIFIED VOLTAGE AT FUSE TERMINAL (FUEL PUMP RELAY CHECKING) Fuse Specified value at one of the terminals S228 (28) approx. battery voltage S232 (32) approx. battery voltage S234 (34) approx. battery voltage

If the specified values are not obtained

1. Repeat test at other terminal of fuse base.

If the specifications are still not obtained

1. Check wiring connections. See appropriate System Wiring Diagram article.

If no DTC is found

1. Replace fuel pump (FP) relay -J17-.
2. Reinsert fuses.

Mass Air Flow (MAF) sensor -G70-, checking

Special tools and equipment

1. VAG1526 A
2. VAG1594 A
3. VAG1598/31
4. VAS5051 with VAS5051/1

Location overview. See COMPONENT LOCATIONS, OVERVIEW .

1. Engine coolant temperature at least 80 °C.
2. Electrical accessories switched off (radiator fan must not run during the test).
3. Air conditioning switched off.

Checking function

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01-Engine electronics" in selection. Engine must be running at idling speed.

Display on VAS5051

Scheme 284

1. Under -1- select diagnostic function "04 - Basic setting".

Display on VAS5051

Scheme 285

1. Enter display group max. input value = 255

1. Enter "002" for "display group number 002" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 286

1. Activate basic setting by pressing -A- button.
2. Check specifications for load recognition in display zones -3- and -4-.

All models

DISPLAY GROUP 002: INTAKE AIR MASS AT IDLE AND OPERATING TEMPERATURE

1. Exit function "04 - Basic setting" by pressing [left arrow] button.

Evaluation of display group 002

EVALUATION OF DISPLAY GROUP 002 (CHECKING MASS AIR FLOW SENSOR)

1. Fuse for mass air flow (MAF) sensor OK. See appropriate System Wiring Diagram article.
2. Fuel pump relay OK; checking. See «FUEL PUMP (FP) RELAY -J17- AND ACTIVATION, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__fuel-pump-fp-relay-j17-and) .

Note. Voltage supply to mass air flow (MAF) sensor is from fuel pump relay.

Scheme 287

1. Disconnect cover -1- on right in engine compartment.
2. Disconnect connector (arrow) to mass air flow (MAF) sensor.
3. Connect multimeter as follows to measure voltage. CONNECTOR TERMINAL 2 VOLTAGE REFERENCE (CHECKING MASS AIR FLOW SENSOR) Connector terminal Measure to 2 Engine ground
4. Operate starter briefly. Specified value: approx. battery voltage

If specified value is not obtained

1. Check wiring from terminal 2 on connector via fuse to fuel pump relay for open circuit or short to Ground: See appropriate System Wiring Diagram article.
2. Repair any open/short circuit as necessary.

If specified value is obtained

1. Connect multimeter between terminals 2 and 3 to measure voltage.
2. Operate starter briefly (engine may start). Specified value: approx. battery voltage NOTE: Engine control module Ground is present at terminal 3 of the connector.

Scheme 288

If specified value is not obtained

1. Check wiring connections. See «CHECKING WIRING TO MASS AIR FLOW (MAF) SENSOR»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__checking-wiring-to-mass-air-flow) .
2. Connect multimeter between terminals 1 and 3 to measure voltage. Specified value: approx. 5 V

If specified value is not obtained

Checking wiring to mass air flow (MAF) sensor

Note. The signal wire is also checked during the wiring check.

Scheme 289

1. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit and short to positive or Ground in following wiring connections: MAF SENSOR OPEN/SHORT CIRCUIT TEST TERMINALS Connector terminal Test box VAG1598/31 Socket 1 53 3 27 4 29
3. Repair any open/short circuit as necessary.
4. Check all wires for short to one another.

If no wiring malfunction is detected

1. Replace mass air flow (MAF) sensor -G70-.

1. VAS5051 with VAS5051/1
2. Engine leak detector spray G 001 800 A1

Note. The vacuum in the intake system will cause the leak detector spray to be drawn in with the unmetered air. The leak detector spray reduces the ignitability of the mixture. This leads to a drop in engine speed and to a significant increase of the CO content. The safety precautions listed on the container must be adhered to.

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01-Engine electronics" in selection. Engine must be running at idling speed.

Display on VAS5051

Scheme 290

1. Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS5051

Scheme 291

1. Enter display group max. input value = 255

1. Enter "001" for "display group number 001" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 292

1. Note engine speed in display zone -1-.
2. Systematically spray parts of intake system with engine leak detector spray.

If engine speed drops

1. Check sprayed areas of intake system for leaks and repair if necessary.
2. Exit function "08 - Read measured value block" by pressing [left arrow] button.

Display on VAS5051

Scheme 293

1. Under -1- select diagnostic function "06 - End output".
2. Switch ignition off.

Intake manifold change-over, checking

Testing should only be performed if the engine is losing power.

The intake manifold change over function switches over from the long intake tract to the short intake tract at about 4200 RPM.

Intake manifold change-over, checking function

1. Remove front engine cover (arrows).
2. Start engine and increase engine speed to well above 4200 rpm. The operating rods of the actuator for the intake manifold (arrow) must move

If the change-over is not taking place, perform the following tests

1. Check intake manifold change-over valve -N156- (Perform final control diagnosis. See «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk__output-diagnostic-test-mode-dtm) . If necessary, check valve and actuation. See «INTAKE MANIFOLD CHANGE-OVER VALVE -N156-, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) or «CHECKING ACTUATION»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) ).
2. Checking vacuum system for leaks. See «VACUUM SYSTEM, CHECKING FOR LEAKS»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
3. Check that vacuum hoses are properly connected and free of leaks and obstructions.
4. Check that change-over mechanism operates freely (move push rod by hand).

1. VAG1348/3-2
2. VAG1348/3A
3. VAG1390
4. VAG1594 A

1. Run engine at idling speed for 2 or 3 minutes to build up vacuum pressure.
2. Switch ignition off.
3. Remove front engine cover (arrows).
4. Disconnect connectors to intake manifold change-over valve -N156- -1-.
5. Connect one terminal on solenoid valve to engine Ground using test leads and alligator clamp from VAG1594 A.
6. Connect second terminal on intake manifold change-over valve -N156- to positive using remote control VAG1348/3A, adapter lead VAG1348/3-2 and auxiliary cable.
7. Operate remote control VAG1348/3A approx. 2 to 3 minutes; throughout this period, vacuum module should remain energized.

If the vacuum module retardations to its original "rest" position, perform the following test

1. Disconnect vacuum hoses from vacuum module for intake manifold change-over system.
2. Connect hand vacuum pump VAG1390 to vacuum module.
3. Operate hand pump and check whether change-over function is working.
4. Check vacuum module for leaks. (Vacuum module should not return to rest position until hand pump is vented to atmosphere.)
5. Replace vacuum module, if necessary.
6. If vacuum module is not energized, check intake manifold change-over valve -N156- as follows for blockage
7. Connect one terminal of intake manifold change-over valve -N156- to engine Ground using test leads and alligator clamp from VAG1594 A.
8. Connect second terminal on intake manifold change-over valve -N156- to positive using remote control VAG1348/3A, adapter lead VAG1348/3-2 and auxiliary cable.
9. Operate remote control VAG1348/3A.
10. Check valve for obstructions (disconnect vacuum hoses and blow through).
11. Replace intake manifold change-over valve, if necessary.
12. If no DTCs have been found in any test, check vacuum system for leaks.

1. VAG1526 A
2. VAG1527 B
3. VAG1594 A
4. VAG1598/31
5. VAS5051 with VAS5051/1

1. Remove front engine cover (arrows).
2. Disconnect connectors to intake manifold change-over valve -N156- -pos. -1-.

Checking internal resistance

1. Connect multimeter to injector to measure resistance. Specified value: 25 to 35 ohms

If specified value is not obtained

1. Replace intake manifold change-over valve -N156-.

If specified value is obtained

1. Fuse for intake manifold change-over valve OK
2. Fuel pump relay OK; checking. See «FUEL PUMP (FP) RELAY -J17- AND ACTIVATION, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__fuel-pump-fp-relay-j17-and) . NOTE: Power supply of the intake manifold change-over valve is via the fuel pump relay.

Scheme 294

1. Connect voltage tester VAG1527 B as follows: CONNECTOR TERMINAL 1 REFERENCE (CHECKING INTAKE MANIFOLD CHANGE-OVER VALVE) Connector terminal Measure to 1 Engine ground
2. Operate starter briefly. LED should illuminate.

If the LED does not illuminate

1. Check wiring from terminal 1 on connector via fuse to fuel pump relay for an open circuit. See appropriate System Wiring Diagram article.
2. Repair open circuit if necessary.

If LED lights up

Checking actuation

1. Connect voltage tester VAG1527 B between terminals 1 and 2.
2. Initiate final control diagnosis. See «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk__output-diagnostic-test-mode-dtm) . Activate intake manifold change-over valve. LED should flash.

If the LED lamp does not flash or if it illuminates continuously

1. Connect test box VAG1598/31 to wiring harness for engine control module; engine control module must not be connected. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit and short to positive or Ground in following wiring connections: CONNECTOR TERMINAL 2, SOCKET 48 REFERENCE (CHECKING INTAKE MANIFOLD CHANGE-OVER VALVE) Connector terminal Test box VAG1598/31 Socket 2 48
3. Repair any open/short circuit as necessary.

If no wiring malfunction is detected

1. Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .

1. VAG1526 A
2. VAG1594 A
3. VAG1598/31
4. VAS5051 with VAS5051/1

1. No leaks in exhaust system
2. Engine coolant temperature at least 80 °C. See display group 004, display zone 3.

1. Connect vehicle diagnostic, testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01-Engine electronics" in selection. Engine must be running at idling speed.

Display on VAS5051

Scheme 295

1. Under -1- select diagnostic function "04 - Basic setting".

Display on VAS5051

Scheme 296

1. Enter display group

1. Enter "030" for "display group number 030" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 297

1. Check specifications in display zones -1- and -3-. NOTE: By increasing the engine speed the specified values are achieved quickly. The "oxygen sensor status" indicates the condition of the oxygen sensor control and the oxygen sensors. DISPLAY GROUP 030: OXYGEN SENSOR STATUS Display zones 1 2 3 4 Display group 030: Oxygen sensor status Display X X X X X X X X X X X X Display Oxygen sensor status, Bank 1, sensor 1 Oxygen sensor status, Bank 1, sensor 2 Oxygen sensor status, Bank 2, sensor 1 Oxygen sensor status, Bank 2, sensor 2 Range 0 = off 1 = on 0 = off 1 = on 0 = off 1 = on 0 = off 1 = on Specif. value 1 1 1 1 1 0 1 1 1 1 1 0 Note: If the specification is not obtained. See «CHECKING BASIC VOLTAGE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__checking-basic-voltage) . If specified value obtained but DTC stored in DTC memory. See «CHECKING OXYGEN SENSOR LEARNED VALUES AND OXYGEN SENSOR CONTROL»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__checking-oxygen-sensor-learned-values-and) . SIGNIFICANCE OF 3-DIGIT READOUT OF DISPLAY GROUP 030 REFERENCE (OXYGEN SENSORS & OXYGEN SENSOR CONTROL BEFORE CATALYTIC CONVERTER) Significance of 3-digit readout of display group 030 X X X Display zones 1...4 X Condition of oxygen sensor heating: 0 = not active; 1 = active X Oxygen sensor condition: 0 = not active; 1 = active X Oxygen sensor control 0 = not active; 1 = active NOTE: The first digit of the 3-digit display (heating) fluctuates between 0 and 1.

Display on VAS5051

Scheme 298

1. Only continue with test if displays have reached "111" in display zones -1- and -3- at least once.
2. Press [left arrow] button.

Checking oxygen sensor learned values and oxygen sensor control

Display on VAS5051

Scheme 299

1. Enter display group

1. Enter "032" for "display group number 032" in zone -2- and confirm entry by pressing -Q- button.
2. Check values in display zones -1- to -4-.

DISPLAY GROUP 032: OXYGEN SENSOR LEARNED VALUES BEFORE CATALYTIC CONVERTER

1. Press [left arrow] button.

Display on VAS5051

Scheme 300

1. Enter display group

1. Enter "033" for "display group number 033" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 301

1. Activate basic setting by pressing -A- button.
2. Check indication in display fields -1- to -4-. DISPLAY GROUP 033: OXYGEN SENSOR CONTROL BEFORE CATALYTIC CONVERTER 1 2 3 4 Display group 033: Oxygen sensor control before catalytic converter Display xx.x% x.xxx V xx.x% x.xxx V Display Oxygen sensor control Bank 1, sensor 1 Oxygen sensor voltage Bank 1, sensor 1 Oxygen sensor control Bank 1, sensor 2 Oxygen sensor voltage Bank 1, sensor 2 Specif. value In range -10.0 to 10.0% value must fluctuate at least 2% 1.400 to 1.600 V In range -10.0 to 10.0% value must fluctuate at least 2% 1.400 to 1.600 V Note: If specified value is not obtained Continuation. See «EVALUATING DISPLAY GROUP 032»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__evaluating-display-group-032) . If specified value is not achieved. See «EVALUATING DISPLAY GROUP 033»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__evaluating-display-group-033) . If specified value is not obtained Continuation. See «EVALUATING DISPLAY GROUP 032»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__evaluating-display-group-032) . If specified value is not achieved Evaluation display group 033. See «EVALUATING DISPLAY GROUP 033»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__evaluating-display-group-033) . Note on display zones 2 and 4: Displayed is the oxygen sensor voltage signal which was prepared and smoothed in the engine control module. 1.5 V in the display corresponds to oxygen sensor 1 (with the engine at operating temperature without secondary air system influence).
3. Exit function "04 - Basic setting" by pressing [left arrow] button.

If specification is not obtained in display zone 1 or display zone 3, or if the value does not fluctuate by at least 2%

1. Perform drive test to free oxygen sensors from any possible residues and repeat test.

If the specified result is not achieved in display zones 1 or 3, or if the value does not fluctuate by at least 2%, even after the test drive

1. Check basic voltage. See «CHECKING BASIC VOLTAGE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__checking-basic-voltage) .
2. Check oxygen sensor heating before catalytic converter. See «OXYGEN SENSORS BEFORE CATALYTIC CONVERTER, CHECKING HEATING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
3. Check oxygen sensor before catalytic converter for aging. See «OXYGEN SENSORS BEFORE CATALYTIC CONVERTER, CHECKING AGING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .

Evaluating display group 032

EVALUATING DISPLAY GROUP 032 (OXYGEN SENSORS & OXYGEN SENSOR CONTROL BEFORE CATALYTIC CONVERTER)

Evaluating display group 033

EVALUATING DISPLAY GROUP 033 (OXYGEN SENSORS & OXYGEN SENSOR CONTROL BEFORE CATALYTIC CONVERTER)

1. Fuse for oxygen sensors OK. See appropriate System Wiring Diagram article.

1. Disconnect 6-pin connector of relevant oxygen sensor before catalytic converter. See «Identification of connector bracket - right side of vehicle»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-right) and «Identification of connector bracket - left side of vehicle»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-left) .
2. Connect multimeter between terminals 1 and 5 to measure voltage.
3. Switch ignition on. Specified value: 0.400 to 0.500 V
4. Switch ignition off.

If specified value is not obtained

1. Check oxygen sensor wiring: Bank 1. See «CHECK OXYGEN SENSOR WIRING, BANK 1, SENSOR 1, HEATED OXYGEN SENSOR (HO2S) -G39»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Bank 2. See «CHECK OXYGEN SENSOR WIRING, BANK 2, SENSOR 1, HEATED OXYGEN SENSOR (HO2S) 2 -G108»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .

If specified value is obtained

1. Replace relevant oxygen sensor before catalytic converter.

Scheme 302

1. Disconnect 6-pin connector of bank 1, Heated Oxygen Sensor (HO2S) -G39-. See «IDENTIFICATION OF CONNECTOR BRACKET - RIGHT SIDE OF VEHICLE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-right) .
2. Connect test box VAG1598/31 to wiring harness for engine control module; engine control module must not be connected. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
3. Test for open circuit in following wiring connections. HO2S CONNECTOR TERMINAL REFERENCE (HO2S BANK 1, SENSOR 1) Connector terminal Test box VAG1598/31 Socket 1 70 2 71 5 51 6 52
4. Repair open circuit, if necessary.
5. Check for shorts between two wires.

If no wiring malfunction is detected

1. Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .

Scheme 303

1. Disconnect 6-pin connector of bank 2, Heated Oxygen Sensor (HO2S) 2 -G108-. See «IDENTIFICATION OF CONNECTOR BRACKET - LEFT SIDE OF VEHICLE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-left) .
2. Connect test box VAG1598/31 to wiring harness for engine control module; engine control module must not be connected. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
3. Test for open circuit in following wiring connections. HO2S CONNECTOR TERMINAL REFERENCE (HO2S BANK 2, SENSOR 1) Connector terminal Test box VAG1598/31 Socket 1 13 2 14 5 12 6 15
4. Repair open circuit, if necessary.
5. Check for shorts between two wires.

If no wiring malfunction is detected

1. Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .

1. VAS5051 with VAS5051/1

1. Engine coolant temperature at least 80 °C. See display group 004, display zone 3.

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01 - Engine electronics" in selection. Engine must be running at idling speed.

Display on VAS5051

Scheme 304

1. Under -1- select diagnostic function "04 - Basic setting".

Display on VAS5051

Scheme 305

1. Enter display group

1. Select function "197" in button field -2- for "display group number 197" and press -Q- button to confirm input.

Display on VAS5051

Scheme 306

1. Activate basic setting by pressing -A- button.
2. Press accelerator and brake pedal simultaneously, engine speed increases to approx. 2200 rpm.

Test conditions

1. Accelerator and brake pedal pressed simultaneously, engine runs at approx. 2200 rpm.

1. Check specifications in display zones -3- and -4-. DISPLAY 197: DIAGNOSIS OF OXYGEN SENSOR AGING (BANK 1, SENSOR 1 - BANK 2, SENSOR 1) (CHECKING AGING, OXYGEN SENSORS BEFORE CATALYTIC CONVERTER) Display zones 1 2 3 4 Display 197: Diagnosis of oxygen sensor aging (Bank 1, sensor 1 - Bank 2, sensor 1) Display x.x - x.x - Display Dynamics factor Bank 1, sensor 1 Diagnosis status Dynamics factor Bank 2, sensor 1 Diagnosis status Range Test OFF Test ON B1-S1 OK B1-S1 NOK Test OFF Test ON B1-S1 OK B1-S1 NOK Specified value 0.6 to 2.5 B1-PS1 NOK 0.6 to 2.5 B1-S1 NOK Note: If specification not obtained. See «OXYGEN SENSORS BEFORE CATALYTIC CONVERTER, CHECKING HEATING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Note on display zones 1 and 3: The dynamics factor is the characteristic for the aging of the oxygen sensor. The lower the dynamics factor the more advanced is the aging of the oxygen sensor.
2. Press [left arrow] button.

If specification in display zone 3 or 4 is not obtained

1. Perform test drive to free oxygen sensors from any possible residues and repeat test.

If specified value in display zone 3 or 4 is not obtained, after a test drive has been performed

1. Replace relevant oxygen sensor before catalytic converter.

1. VAG1526 A
2. VAG1594 A
3. VAG1598/31

1. Fuse for oxygen sensor heating OK

1. Disconnect 6-pin connector of bank 1, Heated Oxygen Sensor (HO2S) -G39-. See «Identification of connector bracket - right side of vehicle»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-right) .
2. Connect multimeter between terminals 3 and 4 to measure resistance. Specified value at room temperature 2.5 to 10 ohms

If specified value is not obtained

1. Replace HO2S -G39-.

If specified value is obtained

Check voltage supply for oxygen sensor heating

1. Connect multimeter between terminals 3 and 4 to measure voltage.
2. Start engine. Specified value: approx. battery voltage NOTE: Points at which oxygen sensor heating is switched on and off by engine control module can be observed in "Reading measured value block" function, display group number 041 and display zone 2.

If no voltage is present

Scheme 307

1. Connect multimeter as follows to measure voltage. CONNECTOR TERMINAL 3 VOLTAGE REFERENCE (CHECKING HEATING, OXYGEN SENSORS BEFORE CATALYTIC CONVERTER) Connector terminal Measure to 3 Engine ground
2. Operate starter briefly. Specified value: approx. battery voltage

If no voltage is present

1. Check wiring from terminal 3 on connector via fuse to fuel pump relay for an open circuit: See appropriate System Wiring Diagram article.

If voltage supply is OK

Scheme 308

1. Connect multimeter as follows to measure voltage: CONNECTOR TERMINAL 4 VOLTAGE REFERENCE (CHECKING HEATING, OXYGEN SENSORS BEFORE CATALYTIC CONVERTER) Connector terminal Measure to 4 (Ground actuation by engine control module) Battery positive
2. Start engine. Specified value: approx. battery voltage NOTE: Points at which oxygen sensor heating is switched on and off by engine control module can be observed in "Reading measured value block" function, display group number 041 and display zone 2.
3. Switch ignition off.

If no voltage is present

Scheme 309

1. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit in following wiring connections: CONNECTOR TERMINAL 4 AND SOCKET 5 REFERENCE (CHECKING HEATING, OXYGEN SENSORS BEFORE CATALYTIC CONVERTER) Connector terminal Test box VAG1598/31 Socket 4 5
3. Repair open circuit, if necessary.

If wiring is OK but there is no Ground supply for the oxygen sensor heating

1. Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .

Oxygen sensors and oxygen sensor control behind catalytic converter, checking

Note. The oxygen sensor before catalytic converter (bank 1, sensor 1 and bank 2, sensor 1) regulates to oxygen sensor 1. If this oxygen sensor is damaged, e.g. due to dirt or overheating, the regulation value may have shifted. Deviations from oxygen sensor 1 are detected by the oxygen sensor behind catalytic converter (bank 1, sensor 2 and bank 2, sensor 2). If it recognizes the deviations downward or upward, it influences the regulation before catalytic converter, generally increasing or decreasing it respectively.

1. VAG1526 A
2. VAG1594 A
3. VAG1598/31
4. VAS5051 with VAS5051/1

1. No leaks in exhaust system
2. Engine coolant temperature at least 80 °C. See display group 004, display zone 3.

1. Connect vehicle diagnostic, testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01-Engine electronics" in selection. Engine must be running at idling speed.

Display on VAS5051

Scheme 310

1. Under -1- select diagnostic function "04 - Basic setting".

Display on VAS5051

Scheme 311

1. Enter display group

1. Enter "030" for "display group number 030" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 312

1. Activate basic setting by pressing -A- button.
2. Check specifications in display zones -2- and -4-. NOTE: By increasing the engine speed the specified values are achieved more quickly. The "oxygen sensor status" indicates the condition of the oxygen sensor control and the oxygen sensor. DISPLAY GROUP 030: OXYGEN SENSOR STATUS (OXYGEN SENSORS & OXYGEN SENSOR CONTROL BEHIND CATALYTIC CONVERTER) Display zones 1 2 3 4 Display group 030: Oxygen sensor status Display X X X X X X X X X X X X Display Oxygen sensor status, Bank 1, sensor 1 Oxygen sensor status Bank 1, sensor 2 Oxygen sensor status, Bank 2, sensor 1 Oxygen sensor status Bank 2, sensor 2 Range 0 = off 1 = on 0 = off 1 = on 0 = off 1 = on 0 = off 1 = on Specif. value 1 1 1 1 1 0 1 1 1 1 1 0 Note: If the specification is not obtained. See «OXYGEN SENSORS BEHIND CATALYTIC CONVERTER, CHECKING HEATING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . SIGNIFICANCE OF 3-DIGIT READOUT OF DISPLAY GROUP 030 (OXYGEN SENSORS & OXYGEN SENSOR CONTROL BEHIND CATALYTIC CONVERTER) Significance of 3-digit readout of display group 030 X X X Display zones 1...4 X Condition of oxygen sensor heating: 0 = not active; 1 = active X Oxygen sensor condition: 0 = not active; 1 = active X Oxygen sensor control 0 = not active; 1 = active NOTE: The first digit of the 3-digit display (heating) fluctuates between 0 and 1. The oxygen sensor control for oxygen sensor behind catalytic converter (bank 1, sensor 2 and bank 2, sensor 2) is not active without engine load, i.e. the last digit of the 3-digit display is 0.

Display on VAS5051

Scheme 313

1. Continue with test if displays have reached "110" in display zones -2- and -4- at least once.
2. Press [left arrow] button.

Checking oxygen sensor control behind catalytic converter

Display on VAS5051

Scheme 314

1. Enter display group max. input value = 255

1. Enter "037" for "display group number 037" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 315

1. Activate basic setting by pressing -A- button.
2. Check oxygen sensor voltage in display zone -2-.
3. Check oxygen sensor correction value in display zone -3- and diagnosis result in display zone -4-.

DISPLAY GROUP 037: DIAGNOSIS, OXYGEN SENSOR CONTROL SYSTEM (BANK 1, SENSOR 2) (OXYGEN SENSORS & OXYGEN SENSOR CONTROL BEHIND CATALYTIC CONVERTER)

Note on display zone 2

The oxygen sensor voltage Bank 1, sensor 2 should be kept as constant as possible. Strong voltage fluctuations indicate a damaged catalytic converter.

1. Press [left arrow] button.

Display on VAS5051

Scheme 316

1. Enter display group

1. Enter "038" for "display group number 038" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 317

1. Activate basic setting by pressing -A- button.
2. Check oxygen sensor voltage in display zone -2-.
3. Check oxygen sensor correction value in display zone -3- and diagnosis result in display zone -4-.

DISPLAY GROUP 038: DIAGNOSIS, OXYGEN SENSOR CONTROL SYSTEM (BANK 2, SENSOR 2) (OXYGEN SENSORS & OXYGEN SENSOR CONTROL BEHIND CATALYTIC CONVERTER)

Note on display zone 2

The oxygen sensor voltage Bank 2, sensor 2 should be kept as constant as possible. Strong voltage fluctuations indicate a damaged catalytic converter.

1. Exit function "04 - Basic setting" by pressing [left arrow] button.

Evaluation of display groups 037 and 038

EVALUATION OF DISPLAY GROUPS 037 AND 038 (OXYGEN SENSORS & OXYGEN SENSOR CONTROL BEHIND CATALYTIC CONVERTER)

If specification in display zone 3 or 4 is not obtained

1. Perform test drive to free oxygen sensors from any possible residues and repeat test.

If specified value in display zone 3 or 4 is not obtained, even after a test drive has been performed

1. Replace relevant oxygen sensor before catalytic converter. NOTE: If the oxygen sensor voltage is OK and after a road test the oxygen sensor correction value is still outside the specification, this indicates aging of the oxygen sensor before catalytic converter.

Checking basic voltage

1. Disconnect 4-pin connector of relevant oxygen sensor behind catalytic converter. See «IDENTIFICATION OF CONNECTOR BRACKET - RIGHT SIDE OF VEHICLE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-right) or «IDENTIFICATION OF CONNECTOR BRACKET - LEFT SIDE OF VEHICLE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-left) .
2. Connect multimeter between terminals 3 and 4 to measure voltage.
3. Switch ignition on. Specified value: 0.400 to 0.500 V
4. Switch ignition off.

If specified value is not obtained

1. Check oxygen sensor wiring Bank 1. See «CHECKING OXYGEN SENSOR WIRING, BANK 1 OXYGEN SENSOR (O2S) BEHIND THREE WAY CATALYTIC CONVERTER (TWC) -G130»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) . Bank 2. See «CHECKING OXYGEN SENSOR WIRING, BANK 2 OXYGEN SENSOR (O2S) 2 BEHIND THREE WAY CATALYTIC CONVERTER (TWC) -G131»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .

If specified value is obtained

1. Replace relevant oxygen sensor behind catalytic converter.

Scheme 318

1. Disconnect 4-pin connector, bank 1, Oxygen Sensor (O2S) behind three way catalytic converter (TWC) -G130-. See «IDENTIFICATION OF CONNECTOR BRACKET - RIGHT SIDE OF VEHICLE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-right) .
2. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
3. Test for open circuit in following wiring connections. HO2S CIRCUIT TEST (OXYGEN SENSORS & OXYGEN SENSOR CONTROL BEHIND CATALYTIC CONVERTER) Connector terminal Test box VAG1598/31 Socket 3 68 4 69
4. Repair open circuit, if necessary.
5. Check for shorts between two wires.

If no wiring malfunction is detected

1. Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .

Scheme 319

1. Disconnect 4-pin connector, bank 2, oxygen sensor (O2S) 2 behind three way catalytic converter (TWC) -G131-. See «IDENTIFICATION OF CONNECTOR BRACKET - LEFT SIDE OF VEHICLE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-left) .
2. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
3. Test for open circuit in following wiring connections. HO2S CIRCUIT TEST (OXYGEN SENSORS & OXYGEN SENSOR CONTROL BEHIND CATALYTIC CONVERTER) Connector terminal Test box VAG1598/31 Socket 3 10 4 11
4. Repair open circuit, if necessary.
5. Check for shorts between two wires.

If no wiring malfunction is detected

1. Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .

1. VAS5051 with VAS5051/1

1. Engine coolant temperature at least 80 °C. See display group 004, display zone 3.

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01-Engine electronics" in selection. Engine must be running at idling speed.

Display on VAS5051

Scheme 320

1. Under -1- select diagnostic function "04 - Basic setting".

Display on VAS5051

Scheme 321

1. Enter display group

1. Enter "194" for "display group number 194" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 322

1. Activate basic setting by pressing -A- button.
2. Press accelerator and brake pedal simultaneously, engine speed increases to approx. 2200 rpm.

1. Accelerator and brake pedal pressed simultaneously, engine runs at approx. 2200 rpm.

1. Check specification in display zones -3- and -4-. DISPLAY GROUP 194: DIAGNOSIS OF OXYGEN SENSOR AGING (BANK 1, SENSOR 2 - BANK 2, SENSOR 2) (CHECKING AGING, OXYGEN SENSORS BEHIND CATALYTIC CONVERTER) Display zones 1 2 3 4 Display group 194: Diagnosis of oxygen sensor aging (Bank 1, sensor 2 - Bank 2, sensor 2) Display xxxx rpm xxx °C - - Display Engine speed Exhaust gas temperature Diagnosis status Diagnosis status Range Test OFF Test ON B1-S2 OK B1-S2 NOK Test OFF Test ON B1-S2 OK B1-S2 NOK Specif. value approx. 2200 rpm Above 350 °C B1-S2 OK B2-S2 OK Note: If "B1-S2 NOK" or "B2-S2 NOK" is displayed, continuation. See «OXYGEN SENSORS BEHIND CATALYTIC CONVERTER, CHECKING HEATING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .
2. Press [left arrow] button.

If specification in display zones -3- and -4- is not obtained

1. Perform test drive to free oxygen sensors from any possible residues and repeat test.

If specification in display zones -3- and -4- is not obtained even after a test drive has been performed

1. Replace relevant oxygen sensor behind catalytic converter.

1. VAG1526 A
2. VAG1594 A
3. VAG1598/31

1. Fuse for oxygen sensor heating OK. See appropriate System Wiring Diagram article.

1. Disconnect 4-pin connector of relevant oxygen sensor behind catalytic converter. See «IDENTIFICATION OF CONNECTOR BRACKET - RIGHT SIDE OF VEHICLE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-right) or «IDENTIFICATION OF CONNECTOR BRACKET - LEFT SIDE OF VEHICLE»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-left) .
2. Connect multimeter between terminals 1 and 2 to measure resistance. Specified value at room temperature 6.4 to 47.5 ohms

If specified value is not obtained

1. Replace relevant oxygen sensor behind catalytic converter.

If specified value is obtained

1. Connect multimeter between terminals 1 (positive) and 2 (Ground) to measure voltage.
2. Start engine. Specified value: approx. battery voltage NOTE: Points at which oxygen sensor heating is switched on and off by engine control module can be observed in "Reading measured value block" function, display group number 041 and display zone 4.

If no voltage is present

Scheme 323

1. Connect multimeter as follows to measure voltage: CONNECTOR TERMINAL 1 VOLTAGE REFERENCE (CHECKING HEATING, OXYGEN SENSORS BEHIND CATALYTIC CONVERTER) Connector terminal Measure to 1 Engine ground
2. Operate starter briefly. Specified value: approx. battery voltage

If no voltage is present

1. Check wiring from terminal 1 on connector via fuse to fuel pump relay for an open circuit

If voltage supply is OK

Scheme 324

1. Connect multimeter as follows to measure voltage: CONNECTOR TERMINAL 2 VOLTAGE REFERENCE (CHECKING HEATING, OXYGEN SENSORS BEHIND CATALYTIC CONVERTER) Connector terminal Measure to 2 (ground activation by engine control module) Battery positive
2. Start engine. Specified value: approx. battery voltage, may fluctuate
3. Switch ignition off.

If no voltage is present

Scheme 325

1. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit in following wiring connections: Oxygen sensor (O2S) heater 1 -Z29- Bank 1 behind Cat: CONNECTOR TERMINAL 2 AND SOCKET 63 REFERENCE (CHECKING HEATING, OXYGEN SENSORS BEHIND CATALYTIC CONVERTER) Connector terminal Test box VAG1598/31 Socket 2 63 Oxygen Sensor (O2S) heater 2 -Z30- Bank 2 behind Cat: CONNECTOR TERMINAL 2 AND SOCKET 6 REFERENCE (CHECKING HEATING, OXYGEN SENSORS BEHIND CATALYTIC CONVERTER) Connector terminal Test box VAG1598/31 Socket 2 6
3. Repair open circuit, if necessary.

If wiring is OK but there is no Ground (GND) supply for oxygen sensor heater

1. Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .

1. VAS5051 with VAS5051/1

1. Engine coolant temperature at least 80 °C. See display group 004, display zone 3.

1. Connect vehicle diagnostic, testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01 - Engine electronics" in selection. Engine must be running at idling speed.

1. Engine running at idling speed

Display on VAS5051

Scheme 326

1. Under -1- select diagnostic function "04 - Basic setting".

Display on VAS5051

Scheme 327

1. Enter display group

1. Enter "196" for "display group number 196" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 328

1. Activate basic setting by pressing -A- button.
2. Check specification in display zone -4-.

All models

DISPLAY GROUP 196: DIAGNOSIS OF OXYGEN SENSOR INTERCHANGE RECOGNITION (BANK 1, SENSOR 2 - BANK 2, SENSOR 2)

1. Exit function "04 - Basic setting" by pressing [left arrow] button.

1. Box wrench set 3337
2. High-temperature paste G 052 112 A3

1. Disconnect connector of relevant oxygen sensor. See «Identification of connector bracket - right side of vehicle»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-right) or «Identification of connector bracket - left side of vehicle»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__identification-of-connector-bracket-left) .
2. Undo cable ties.
3. Remove oxygen sensor using special tool 3337.

When installing, note the following points

Note. The screw thread on the oxygen sensor is coated with assembly paste. This paste must not be allowed to penetrate the openings on the sensor. When installing, the cable ties must be re-installed at exactly the same points in order to prevent contact between the oxygen sensor wire and the exhaust pipe. Tightening torque 55 N.m.

1. 3337 wrench, 7-piece set
2. High temperature paste G 052 112 A3

Removing left oxygen sensor behind catalytic converter

1. Remove rear engine cover (arrows).
2. Remove cover -1- in engine compartment (left side).
3. Remove coolant reservoir (arrow)
4. Disconnect electrical wiring to Engine Coolant Level (ECL) Warning Switch -F66- at bottom of expansion tank.
5. Tie coolant expansion tank with connected coolant hoses -1 to 3- to side.

Vehicles with automatic transmission

1. Disconnect vacuum hose to brake booster (arrows).

1. Remove heat shield for harness connectors at left of bulkhead, if installed.
2. Remove harness connectors -1- to -4- from bracket at left of bulkhead.
3. Disconnect electrical harness connector -1-.
4. Move wire to oxygen sensor clear.
5. Remove oxygen sensor behind catalytic converter (arrow) using special tool 3337/7. NOTE: Illustration is shown with engine removed.

Scheme 329

1. Remove rear engine cover (arrows).
2. Remove cover -1- in engine compartment (right side).
3. Remove bolts (arrows).
4. Disconnect Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80- -1- at air guide.
5. Remove air guide -2-.
6. Remove air filter housing (arrows).
7. Remove bolts for holding plate -3- for solenoid valves (arrows).
8. Disconnect electrical harness connector at Mass Air Flow (MAF) sensor.
9. Remove hose -4- of crankshaft housing ventilation from air guide -2-.
10. Remove bolt (arrow) and disconnect air guide -2- at throttle valve control module.
11. Disconnect hose -1- from air guide. NOTE: Illustration depicts air guide with the removed engine from rear.
12. Remove harness connectors -1- to -4- from bracket at right of bulkhead.
13. Disconnect electrical harness connector -3-.
14. Move wire to oxygen sensor clear.
15. Remove oxygen sensor behind catalytic converter (arrow) using special tool 3337/7. NOTE: Illustration is shown with engine removed.

Installation is reverse of removal, noting the following

Note. Oxygen sensor threads are coated with an assembly paste. This paste must not be allowed to enter the sensor openings. Cable ties must always be installed again in exactly the same place to prevent the sensor wire from contacting the exhaust pipe. Tightening torque: 55 N.m

1. VAG1526 A
2. VAG1527 B
3. VAG1594 A
4. VAG1598/31
5. VAS5051 with VAS5051/1

1. When there is no electrical supply, solenoid valve remains closed.
2. Disconnect hoses from EVAP canister purge regulator valve but leave electrical connector plugged in.
3. Connect auxiliary hose to one connection of EVAP canister purge regulator valve.
4. Connect testing and information system VAS5051 and select vehicle system "01 - Engine electronics" in selection. Ignition must be switched on.
5. Initiate final control diagnosis and activate EVAP canister purge regulator valve -N80-. See «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk__output-diagnostic-test-mode-dtm) . The valve should click... ... and should open and close (check by blowing into the auxiliary hose).
6. Press [left arrow] button to end function "03 - Final Control Diagnosis" [also known as Output Diagnosis Test Mode (DTM)]. If valve does not open and close properly
7. Replace EVAP canister purge regulator valve -N80-. If the injector does not click

Scheme 330

1. Disconnect connector on EVAP canister purge regulator valve.
2. Connect multimeter to injector to measure resistance. Specified value: 22 to 30 ohms If specification is not obtained
3. Replace Evaporative Emission (EVAP) canister purge regulator valve -N80-. If specified value is obtained

1. Fuse for EVAP canister purge regulator valve OK.

See appropriate System Wiring Diagram article.

1. Fuel pump relay OK; checking. See «FUEL PUMP (FP) RELAY -J17- AND ACTIVATION, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__fuel-pump-fp-relay-j17-and) .

Note. The EVAP canister purge regulator valve receives its power supply via the fuel pump relay.

Scheme 331

1. Disconnect connector on EVAP canister purge regulator valve.
2. Connect voltage tester VAG1527 B as follows: CONNECTOR TERMINAL 1 VOLTAGE REFERENCE (EVAPORATIVE EMISSION CANISTER PURGE REGULATOR VALVE) Connector terminal Measure to 1 Engine ground
3. Operate starter briefly (engine may start). LED should illuminate.

If the LED does not illuminate

1. Check wiring from terminal 1 on connector via fuse to fuel pump relay for an open circuit.
2. Repair open circuit, if necessary. If the LED illuminates

1. Connect voltage tester VAG1527 B to terminals 1 (positive) and 2 of connector.
2. Initiate final control diagnosis and activate Evaporative Emission (EVAP) canister purge regulator valve -N80-. See «OUTPUT DIAGNOSTIC TEST MODE (DTM)»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk__output-diagnostic-test-mode-dtm) . LED should flash.

If the LED lamp does not flash or if it illuminates continuously

Scheme 332

1. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit and short to positive or Ground in following wiring connection: CONNECTOR TERMINAL 2 AND SOCKET 64 REFERENCE (EVAPORATIVE EMISSION CANISTER PURGE REGULATOR VALVE) Connector terminal Test box VAG1598/31 Socket 2 64
3. Repair any open/short circuit as necessary. If the wiring is OK
4. Replace engine control module. See «ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__engine-control-module-ecm-without-metal) .

Function of the electronic throttle system

In the electronic throttle system, the throttle valve is not operated by a cable connected to the accelerator pedal. There is no mechanical connection between the accelerator pedal and the throttle valve.

The position of the accelerator pedal is communicated to the engine control module by two accelerator position sensors (variable resistances located in a single housing) connected to the accelerator pedal.

The position of the accelerator pedal (decided by the driver) is one of the main input parameters to the engine control module.

The throttle valve is activated, over the full range of engine speed and power, by an electric motor (throttle valve actuator) in the throttle valve control module.

The throttle valve actuator moves the throttle valve as instructed by the engine control module.

With the ignition switched on and the engine not running, the engine control module controls the throttle valve precisely in accordance with the signals from the accelerator position sensors. This means that when the accelerator is pressed half way down, the throttle valve actuator opens the throttle valve to an equivalent extent; the throttle valve is then about half open.

When the engine is running (and under load), the engine control module can open and close the throttle valve independently of the accelerator position sensors.

As an example, the throttle valve can be fully open even though the accelerator pedal is only pressed half way down. This has the advantage of preventing throttle losses at the throttle valve.

Under certain engine load conditions, markedly improved emission and consumption figures are also obtained.

The engine torque necessary can be provided by the engine control module by an optimum combination of throttle opening and boost pressure.

The electronic throttle system does not simply consist of one or two components, rather a system which includes all the components which contribute to determining the position of the throttle valve and to controlling and monitoring this position. These components include, for example, the throttle valve control module, the EPC warning lamp, the engine control module.

Malfunction lamp for electronic throttle in instrument cluster

Note. The Electronic Power Control (EPC) Warning Lamp -K132- is also known as the EPC warning lamp.

"EPC" is an abbreviation for Electronic Power Control and refers to the electronic throttle control system.

When the ignition is switched on, the engine control module checks all the components of importance to the electronic throttle system.

After switching on the ignition the engine control module switches on the EPC warning lamp. The EPC warning lamp goes out shortly after starting the engine, if on the one hand, the engine control module does not detect any malfunctions in the EPC system, and, if actuation of the lamp by the engine control module is OK.

If a malfunction is detected in the electronic throttle system while the engine is running, the engine control module switches on the EPC warning lamp. (These DTCs are listed in the DTC table). At the same time, an entry is made in the engine control module Diagnostic Trouble Code (DTC) memory.

Functional check on EPC warning lamp

1. Switch ignition on. The engine control module switches on the EPC warning lamp.
2. Start engine. Shortly after starting the engine the EPC warning lamp goes out if no DTC in relation to the electronic throttle is stored in the DTC memory.

Note. The switch-on signal for the malfunction lamp is transferred via CAN bus to the instrument cluster by the engine control module. Check the data exchange between engine control module and other CAN-control modules. See DATA EXCHANGE BETWEEN ENGINE CONTROL MODULE AND OTHER CAN-CONTROL MODULES, CHECKING .

Throttle valve control module -J338-, checking

The following components are located in the housing of the throttle valve control module.

1. Throttle drive (power accelerator actuation) -G186- (This is an electric motor which is activated by the engine control module. This electric motor opens the throttle valve against the force of a spring).
2. Angle sensor -1- for throttle drive (power accelerator actuation) -G187
3. Angle sensor -2- for throttle drive (power accelerator actuation) -G188

Note. Housing for throttle valve control module must not be opened. The angle sensors are in the form of potentiometers (variable resistances). They provide the position of the throttle valve to the engine control module completely independently of one another. The potentiometers cannot be adjusted mechanically. The settings are made as part of basic setting (function 04) using the vehicle diagnosis, measurement and information system VAS5051.

Throttle valve control module -J338-, adaptation

The adaptation process enables the engine control module to learn the various positions of the throttle valve with the ignition switched on and the engine not running. These positions are stored in the control module. The feedback signal indicating the position of the throttle valve comes from the two throttle valve actuator angle sensors.

If the Throttle valve control module -J338- or the engine control module are removed, installed or replaced or if the voltage supply from the engine control module is interrupted, adaptation must always be performed.

The learning process (adaptation process) is performed

1. Automatically if the ignition is switched on once for at least 10 seconds without activating the starter or the accelerator pedal and the engine control module recognizes "adaptation requirement". In this case, it is not obvious whether the adaptation process was successful or not. Adaptation requirement is recognized if stored voltage values from the angle sensors do not coincide with current measured voltage values in a certain tolerance band.
2. By initiating the basic setting (Function 04) of display group 060 with ignition switched on.

Note. Engine will not start during automatic adaptation.

1. VAS5051 with VAS5051/1

Requirements

1. No DTCs recorded in DTC memory; check Diagnostic Trouble Code (DTC) memory. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) .
2. Engine stopped, ignition switched on
3. Accelerator pedal not depressed.
4. Engine coolant temperature 10 to 95 °C
5. Intake air temperature 10 to 90 °C
6. Voltage supply to engine control module greater than 12.7 V, Testing. See «ENGINE CONTROL MODULE (ECM) POWER SUPPLY, CHECKING»(/audi/a4/b6-2000-2006/remont/ignition-system/#ignitionglow-plug-system-30l-avk) .

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01-Engine electronics" in selection. Ignition must be switched on.

Display on VAS5051

Scheme 333

1. Under -1- select diagnostic function "04 - Basic setting".

Display on VAS5051

Scheme 334

1. Enter display group

1. Enter "060" for "display group number 060" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 335

1. Activate basic setting by pressing -A- button.
2. Check specifications for throttle valve control module in display zones -3- and -4-.

The throttle valve actuator is first connected without current.

In this condition, the throttle valve is pulled into an emergency running position by a mechanical spring which is located in the throttle valve control module. The values supplied by the two angle sensors in this emergency running position are stored in the engine control module.

The throttle valve is then opened by a predetermined amount. When this value is reached, the throttle valve actuator is again disconnected from the electricity supply. The mechanical spring should then close the throttle valve to the previously learned emergency running position within a specified period of time (spring test).

The throttle valve actuator then closes the throttle valve; the values supplied by the angle sensors in the throttle valve control module are stored in the engine control module.

If the engine control module disconnects the throttle valve actuator from the electricity supply while the vehicle is being driven, the result will be an increased and fluctuating idling speed and a very poor throttle response.

DISPLAY GROUP 060: ADAPTATION OF THROTTLE VALVE CONTROL MODULE

Note. "ADP" in display zone 4 stands for "Adaptation".

Note. If the adaptation is interrupted by the control module, the reason could be one of the following: The throttle valve cannot close completely (e.g. dirt). The battery voltage is too low. Throttle valve control module or wiring is faulty. Engine was started or accelerator was activated during the adaptation process. Distortion of throttle valve housing (check screw connection). When adaptation process is interrupted, message "Function is unknown or cannot be carried out at the moment" is displayed on tester. The next time the ignition is switched on (for several seconds), the adaptation process is automatically performed again.

1. Exit function "04 - Basic setting" by pressing [left arrow] button.

Angle sensor for throttle valve actuator, checking

Special tools and equipment

1. VAG1526 A
2. VAG1594 A
3. VAG1598/31
4. VAS5051 with VAS5051/1

The Angle sensor -1- for throttle drive (power accelerator actuation) -G187- and Angle sensor -2- for throttle drive (power accelerator actuation) -G188- signal the position of the throttle valve to the engine control module. Both angle sensors are located in the throttle valve control module.

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01 - Engine electronics" in selection. Ignition must be switched on.

Display on VAS5051

Scheme 336

1. Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS5051

Scheme 337

1. Enter display group

1. Enter "062" for "display group number 062" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 338

1. Check specified values for electronic throttle potentiometer voltages in display zones -1- and -2-.

DISPLAY GROUP 062: ELECTRONIC THROTTLE POTENTIOMETER VOLTAGES

Note. The engine control module converts and displays the voltage readings from the angle sensors as percentages of 5 V. (A 5 Volt supply corresponds to 100%).

1. Observe readouts in display zones 1 and 2.
2. Slowly depress accelerator pedal.

Percentage displayed in zone 1 should rise evenly. Tolerance range from 3 to 93% is not fully utilized.

Percentage displayed in zone 2 should fall evenly. Tolerance range from 97 to 3% is not fully utilized.

Note. The reason why the value in display zone 1 rises and that in zone 2 falls is that the potentiometers (angle sensors) in the throttle valve control module operate in opposite directions. This means that the voltage picked off by one of the angle sensors runs in the direction of 5 V. (As the throttle is opened, the voltage becomes greater and the percentage increases). The voltage picked off by the angle sensor 2 runs from 5 V in the direction of 0 V. (As the throttle is opened, the voltage becomes smaller and the percentage decreases).

1. Exit function "08 - Read measured value block" by pressing [left arrow] button.

If the displays are not as described

1. Check throttle valve control module voltage supply and wiring. See «CHECKING THE VOLTAGE SUPPLY TO THE THROTTLE VALVE CONTROL MODULE.»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__checking-the-voltage-supply-to-the) . Pay particular attention to connectors, which may be disconnected or corroded.
2. Check accelerator position sensor. See «ACCELERATOR POSITION SENSOR, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .

Checking the voltage supply to the throttle valve control module

1. Disconnect connector from throttle valve control module.
2. Switch ignition on.
3. Connect multimeter as follows to measure voltage

CONNECTOR TERMINAL 2 + GROUND, 2 + 6 SPECIFIED VALUE REFERENCE (ANGLE SENSOR FOR THROTTLE VALVE ACTUATOR)

If the specified values are not obtained

Checking wiring

1. Disconnect connector from throttle valve control module.
2. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
3. Check for open circuit and short to Ground/positive or Ground in following wiring connections: CONNECTOR TERMINAL 1-6 AND SOCKET 92, 83, 117, 84, 118, 91 REFERENCE (THROTTLE VALVE ACTUATOR) Connector terminal Test box VAG1598/31 Socket 1 92 2 83 3 117 4 84 5 118 6 91
4. Repair any open/short circuit as necessary.

If no wiring malfunction is detected

1. Replace throttle valve control module.

1. VAG1526 A
2. VAG1594 A
3. VAG1598/31
4. VAS5051 with VAS5051/1

Both Throttle Position (TP) sensor -G79- and Sender -2- for accelerator pedal position -G185- are located on the accelerator pedal and completely independently signal the driver's requirements to the engine control module. Both sensors are located in one housing.

1. Connect vehicle diagnostic, testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01 - Engine electronics" in selection. Ignition must be switched on.

Display on VAS5051

Scheme 339

1. Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS5051

Scheme 340

1. Enter display group

1. Enter "062" for "display group number 062" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 341

1. Check specified values for electronic throttle potentiometer voltages in display zones -3- and -4-.

DISPLAY GROUP 062: ELECTRONIC THROTTLE POTENTIOMETER VOLTAGES (ACCELERATOR POSITION SENSOR)

Note. The engine control module converts and displays the voltage readings from the angle sensors as percentages of 5 V. (A 5 Volt supply corresponds to 100%).

1. Observe readouts in display zones 3 and 4.
2. Slowly depress accelerator pedal.

Percentage displayed in zone 3 should rise evenly. Tolerance range from 12 to 97% is not fully utilized.

Percentage displayed in zone 4 should also rise evenly. Tolerance range from 4 to 49% is not fully utilized.

Note. The value displayed in zone 3 must always be about twice as large as that in zone 4.

1. Exit function "08 - Read measured value block" by pressing [left arrow] button.

If the displays are not as described

1. Check voltage supply and wiring for accelerator position sensor. See «CHECKING VOLTAGE SUPPLY FOR ACCELERATOR POSITION SENSORS»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk) .

If the displays are not as described

Scheme 342

1. Remove driver's storage compartment: For Cabriolet models, see «DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW»(ref-197209-S29048734852005101300000) . For models other than Cabriolet, see «DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__driver-side-storage-compartment-with-and-without) .
2. Disconnect connector for accelerator position sensors.
3. Switch ignition on.
4. Connect multimeter as follows to measure voltage: CONNECTOR TERMINAL 1 + GROUND, 1 + 5, 2 + GROUND, 2 + 3 SPECIFIED VALUE REFERENCE (ACCELERATOR POSITION SENSOR) Connector terminal Specified value 1 + ground approx. 5 V 1 + 5 approx. 5 V 2 + ground approx. 5 V 2 + 3 approx. 5 V

If specifications are obtained

1. Additionally check signal wires.

If the specified values are not obtained

Scheme 343

1. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit and short to positive or Ground in following wiring connection: CONNECTOR TERMINAL 1-6 AND SOCKET 72, 73, 36, 35, 33, 34 REFERENCE (ACCELERATOR POSITION SENSOR) Connector terminal Test box VAG1598/31 Socket 1 72 2 73 3 36 4 35 5 33 6 34
3. Repair any open/short circuit as necessary.

If no wiring malfunction is detected

1. Replace accelerator position sensors. See «ACCELERATOR PEDAL MODULE WITH ACCELERATOR POSITION SENDER, REMOVING AND INSTALLING»(/audi/a4/b6-2000-2006/remont/fuel-system/#fuel-supply) .

Kickdown function, adapting

If accelerator pedal position sensors or engine control module are replaced kick down function must be adapted on vehicles with automatic transmission.

1. VAS5051 with VAS5051/1

Preconditions

1. No DTCs recorded in DTC memory; check Diagnostic Trouble Code (DTC) memory. See «DIAGNOSTIC TROUBLE CODE (DTC) MEMORY»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) .
2. Engine stopped, ignition switched on

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01-Engine electronics" in selection. Ignition must be switched on.

Display on VAS5051

Scheme 344

1. Under -1- select diagnostic function "04 - Basic setting".

Display on VAS5051

Scheme 345

1. Enter display group

1. Enter "063" for "display group number 063" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 346

1. Activate basic setting by pressing -A- button.

Note. You will now be instructed to: "Operate kick down".

1. Fully depress accelerator pedal beyond kickdown point and keep it pressed.

Note. During the kickdown point adaptation process, "Kickdown ADP running" is shown on the display. After successful adaptation of the kickdown point "Kickdown ADP OK" appears on the display.

1. Check indication in display field -4-.

DISPLAY GROUP 063: ADAPTING KICKDOWN FUNCTION

Note. "ADP" in display zone 4 stands for adaptation. If "ERROR" can be displayed, if e.g. accelerator pedal is not pressed when instructed by tester, or if accelerator pedal was released while adaptation was already running but process was not yet complete. In both cases it is necessary to exit the "Basic setting" mode and restart the adaptation process afresh. See KICKDOWN FUNCTION, ADAPTING .

1. VAG1526 A
2. VAG1527 B
3. VAG1594 A
4. VAG1598/31
5. VAS5051 with VAS5051/1

Note. Command from accelerator pedal sensor (potentiometer) to engine control module for opening throttle valve is suppressed for safety reasons when brake is pressed. For this purpose, the control module requires signals from both the brake light switch and the brake pedal switch. If the brakes are activated when the accelerator pedal is held at a constant position, the engine speed is immediately reduced to idling speed. Incorrectly adjusted switches may lead to unwanted regulating actions.

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01 -Engine electronics" in selection. Ignition must be switched on.

Display on VAS5051

Scheme 347

1. Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS5051

Scheme 348

1. Enter display group

1. Enter "066" for "display group number 066" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 349

1. Check indication in display field -2-.

DISPLAY GROUP 066: SIGNALS TO ENGINE CONTROL MODULE (BRAKE LIGHT SWITCH & BRAKE PEDAL SWITCH)

1. Exit function "08 - Read measured value block" by pressing [left arrow] button.

If the display is not as described

Check switch

1. Remove driver's storage compartment

For Cabriolet models, see DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW . For models other than Cabriolet, see DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW .

Scheme 350

1. Disconnect connector from brake light/brake pedal switch -2-.
2. Connect multimeter between terminals 1 and 4 to measure resistance. Specified value: INFINITY ohms (no continuity)
3. Press brake pedal. Specified value: approx. 0 ohms
4. Connect multimeter between terminals 2 and 3 to measure resistance. Specified value: approx. 0 ohms
5. Press brake pedal. Specified value: INFINITY ohms (no continuity)

If the specified values are not obtained

1. Replace brake light/brake pedal switch.

See BRAKELIGHT SWITCH .

If specifications are obtained

Scheme 351

1. Connect voltage tester VAG1527 B as follows: CONNECTOR TERMINAL 1 VOLTAGE REFERENCE (BRAKE LIGHT SWITCH & BRAKE PEDAL SWITCH) Connector terminal Measure to 1 Car body Ground point The LED should illuminate. CONNECTOR TERMINAL 3 VOLTAGE REFERENCE (BRAKE LIGHT SWITCH & BRAKE PEDAL SWITCH) Connector terminal Measure to 3 Car body Ground point
2. Switch ignition on. LED should illuminate.

If the LED does not illuminate

1. Check wiring for open circuit and service if necessary.

If the LED illuminates

Scheme 352

1. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit and short to positive or Ground in following wiring connections: CONNECTOR TERMINAL 2, 4 AND SOCKET 55, 56 REFERENCE (BRAKE LIGHT SWITCH & BRAKE PEDAL SWITCH) Connector terminal Test box VAG1598/31 Socket 2 55 4 56
3. Repair any open/short circuit as necessary.

1. VAG1526 A
2. VAG1527 B
3. VAG1594 A
4. VAG1598/31
5. VAS5051 with VAS5051/1

Note. This signal is designed to prevent speed overshoots and jerkiness on switching from throttle open to throttle closed and vice versa when disengaging clutch. It is needed for the cruise control system.

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01 - Engine electronics" in selection. Ignition must be switched on.

Display on VAS5051

Scheme 353

1. Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS5051

Scheme 354

1. Enter display group

1. Enter "066" for "display group number 066" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 355

1. Check indication in display field -2-.

DISPLAY GROUP 066: SIGNALS TO ENGINE CONTROL MODULE

1. Exit function "08 - Read measured value block" by pressing [left arrow] button.

If the display is not as described

Scheme 356

1. Remove driver's storage compartment: For Cabriolet models, see «DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW»(ref-197209-S29048734852005101300000) . For models other than Cabriolet, see «DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW»(/audi/a4/b6-2000-2006/remont/mirrors/#interior-equipment-except-cabriolet__driver-side-storage-compartment-with-and-without) .
2. Disconnect connector from clutch pedal switch -1-.
3. Connect multimeter between terminals 2 and 3 to measure resistance. Specified value: approx. 0 ohms
4. Operate clutch pedal. Specified value: INFINITY ohms (no continuity)

If specified value is not obtained

1. Replace clutch pedal switch.

If specifications are obtained

Scheme 357

1. Connect voltage tester VAG1527 B as follows: CONNECTOR TERMINAL 3 VOLTAGE REFERENCE (CLUTCH PEDAL SWITCH) Connector terminal Measure to 3 Car body Ground point
2. Switch ignition on. LED should illuminate.

If the LED does not illuminate

1. Check wiring for open circuit and service if necessary.

If the LED illuminates

Scheme 358

1. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit and short to positive or Ground in following wiring connection: CONNECTOR TERMINAL 2 AND SOCKET 39 REFERENCE (CLUTCH PEDAL SWITCH) Connector terminal Test box VAG1598/31 Socket 2 39
3. Repair any open/short circuit as necessary.

1. VAG1526 A
2. VAG1594 A
3. VAG1598/31
4. VAS5051 with VAS5051/1

The Cruise Control System (CCS) has no components of its own (except for the operating switch). All cruise control functions are carried out by the engine control module.

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01-Engine electronics" in selection. Ignition must be switched on.

Display on VAS5051

Scheme 359

1. Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS5051

Scheme 360

1. Enter display group

1. Enter "066" for "display group number 066" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 361

1. Check indication in display field -2-.
2. It must be ascertained by a road test whether switch positions are shown in display zone -4-.

DISPLAY GROUP 066: SIGNALS TO ENGINE CONTROL MODULE (CRUISE CONTROL SYSTEM)

1. Exit function "08 - Read measured value block" by pressing "FILLED LEFT TRIANGLE" button.

If "0" appears in display zone 2 even with activated CCS

1. Connect VAG1598/31 test box to wiring harness for engine control module and also to engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Connect multimeter as follows to measure voltage: TEST BOX VAG1598/31 SOCKET 38 VOLTAGE REFERENCE (CRUISE CONTROL SYSTEM) Test box VAG1598/31 Socket Measure to 38 Engine Ground
3. Switch ignition on. Specification for CCS switched off: 0 V Specification for CCS switched on: approx. battery voltage

If the specified values are not obtained

1. Check for open circuit and short to positive or Ground in following wiring connections: TEST BOX VAG1598/31 SOCKET 38 AND TERMINALS REFERENCE (CRUISE CONTROL SYSTEM) Test box VAG1598/31 Socket Steering column electronics control module -J527- terminal 38 See appropriate System Wiring Diagram article.
2. Repair any open/short circuit as necessary.

Significance of 8-digit display in display zone 4

SIGNIFICANCE OF 8-DIGIT DISPLAY IN DISPLAY ZONE 4 (CRUISE CONTROL SYSTEM)

If specifications in display zone 4 are not obtained

1. Check Cruise control switch -E45-.

1. VAG1526 A
2. VAG1527 B
3. VAG1594 A
4. VAG1598/31
5. VAS5051 with VAS5051/1

Vehicles with multitronic 01J

Note. The engine speed signal is output at terminal 37 of the engine control module only in vehicles with multitronic 01J.

1. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit and short to positive or Ground in following wiring connections: TEST BOX VAG1598/31 SOCKET 37 AND INSTRUMENT CLUSTER TERMINAL REFERENCE (ENGINE SPEED SIGNAL) Test box VAG1598/31 Socket Instrument cluster terminal 37 See appropriate System Wiring Diagram article.
3. Repair any open/short circuit as necessary.

If no wiring malfunction is detected

1. Check CAN bus. See «DATA EXCHANGE BETWEEN ENGINE CONTROL MODULE AND OTHER CAN-CONTROL MODULES, CHECKING»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__data-exchange-between-engine-control-module) .

Wiring for crash signal, checking

The engine control module receives the crash signal ("Crash cut-off was activated") from the airbag control module.

The airbag control module sends the crash signal to the engine control module (during an accident or if a final control diagnosis is carried out relating to the airbag system), the engine control module switches off the fuel pump, which stops the engine. It can however be restarted (e.g. to move vehicle out of danger area)

1. Connect test box VAG1598/31 to wiring harness for engine control module; do not connect engine control module. See «WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31»(/audi/a4/b6-2000-2006/remont/fuel-system/#multiport-fuel-injection-mfi-30l-avk__wiring-and-component-check-with-test) .
2. Check for open circuit and short to positive or Ground in following wiring connections: TEST BOX VAG1598/31 SOCKET 67 AND CONTROL MODULE FOR AIRBAG -J234- TERMINAL REFERENCE (WIRING FOR CRASH SIGNAL) Test box VAG1598/31 Socket Control module for Airbag -J234- terminal 67 See appropriate System Wiring Diagram article.
3. Repair any open/short circuit as necessary.

If no wiring malfunction is detected

1. Check Diagnostic Trouble Code (DTC) memory of airbag control module

Data exchange between engine control module and other CAN-control modules, checking

Note. Data is exchanged between individual control modules by means of a bus system. "CAN bus" is used to describe a system that transports and distributes data. The wires between the control modules that are used to transfer the data are known as signal wires. Data is transmitted via data wires in sequence, i.e. in a specific order to the connected control modules (e.g. engine rpm and accelerator pedal position).

Testing the bus system

The DTC table instructed you to check the data exchange between the engine control module and CAN-compatible control modules.

1. Connect testing and information system VAS5051. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) . Select vehicle system "01 - Engine electronics" in selection. Ignition must be switched on.

Display on VAS5051

Scheme 362

1. Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS5051

Scheme 363

1 - Enter display group

Note. The measured value blocks 125 and 126 indicate CAN drive users.

1. Enter "125" for "display group number 125" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS5051

Scheme 364

1. Check displays in display zones -1- to -4-. CAN-compatible control modules are displayed with the engine control module: No display: Engine control module not CAN-compatible Display 1: CAN-compatible control module is a data bus user Display 0: CAN able control module is not user of the Databus
2. To change to display group 126, press the s button.
3. Check same way with display group number 126.
4. Exit function "08 - Read measured value block" by pressing [left arrow] button.

Display on VAS5051

Scheme 365

1. Under -1- select diagnostic function "06 - End output".

Display on VAS5051

Scheme 366

1. Under -1- select diagnostic function "00 - check DTC memory - whole system". The DTC memory is then checked for all systems in the vehicle which are capable of self-diagnosis

If a control module answers with its identification, the number of DTCs stored or "No malfunction detected" appears on the display.

Any system DTCs that are stored are displayed successively. The VAS5051 will then transmit the next address word.

If a DTC is displayed relating to "Data bus drive..."or "... CAN bus"

1. Check that engine control module and other CAN-compatible control modules installed are suitable for this vehicle (part no. and code).

If the correct control modules are installed

1. Check that multiple connectors for control modules are properly seated.

If the multi-pin connectors are firmly seated

1. Check CAN bus system.

Checking a "two-wire bus system"

The communication between three or more control modules is carried out over a "twoline bus system" .

1. Evaluate DTCs stored in control modules.

Note. This helps to localize line malfunctions.

Example 1

The DTCs stored in the DTC memories indicate that the control module 1 does not communicate with control modules 2 and 3.

Scheme 367

DTC CONTROL MODULE CHART (EXAMPLE 1)

1. Switch ignition off.
2. Disconnect control modules linked to one another via bus wires and check whether there is an open circuit between bus wires.

See appropriate System Wiring Diagram article.

1. If no DTC can be detected in bus lines exchange control module 1.

Example 2

The DTCs stored in the DTC memories indicate that the control module 2 does not communicate with control modules 1 and 3.

Scheme 368

DTC CONTROL MODULE CHART (EXAMPLE 2)

1. Switch ignition off.
2. Disconnect control modules linked to one another via bus wires and check whether there is an open circuit between bus wires.

See appropriate System Wiring Diagram article.

1. If no DTC can be detected in bus lines exchange control module 2.

Example 3

The DTCs stored in the DTC memories indicate that sending or receiving is not possible in any of the control modules.

DTC CONTROL MODULE CHART (EXAMPLE 3)

1. Switch ignition off.
2. Disconnect control modules that are linked to one another by bus wires and check bus wires for short circuits to positive and Ground. See appropriate System Wiring Diagram article.

If cause of DTC "Data bus drive faulty" cannot be found in bus lines check whether one of the control modules is responsible for the malfunction .

1. Vehicle diagnosis, measurement and information system VAS5051 connected and vehicle On Board Diagnosis selected. See «VEHICLE DIAGNOSTIC, TESTING AND INFORMATION SYSTEM VAS5051, CONNECTING AND SELECT FUNCTIONS»(/audi/a4/b6-2000-2006/remont/testing-diagnostics/#engine-controls-on-board-diagnostic-obd-30l-avk) .

All the control modules that communicate via the CAN data bus are still disconnected. Ignition is switched off.

1. Connect one control module.

Display on VAS5051

Scheme 369

1. Switch ignition on.
2. Select applicable vehicle system under -1-.
3. Check and erase DTC memory in control module which has just been connected.
4. Press [left arrow] button.
5. Under -1- select diagnostic function "06 - End output".
6. Switch ignition off and then on again.
7. Leave ignition switched on for 10 seconds. Then check DTC memory of control module that has just been connected, using scan tool.
8. If DTC "Data bus drive faulty" is now indicated, replace control module which has just been connected.
9. If DTC "Signal wire defective" is not read out, connect next control module and repeat procedure.

VACUUM HOSE DIAGRAM(S)

Note. The following list refers to see scheme 232.

1. From air filter
2. Secondary Air Injection (AIR) pump motor -V101
3. Throttle valve control module -J338
4. Combi valve for secondary air inlet, right
5. From EVAP canister
6. Evaporative Emission (EVAP) canister purge regulator valve -N80
7. Non-return valve Between intake manifold and brake servo Installation position: as shown in Fig, arrow faces in direction of flow
8. Secondary Air Injection (AIR) solenoid valve -N112- Location: On retainer plate for solenoid valves at rear of engine
9. Brake servo
10. Non-return valve Between intake manifold and solenoid valves Installation position: as shown in Fig, arrow faces in direction of flow
11. Combi valve for secondary air inlet, left
12. Non-return valve Between brake servo pump and brake servo For vehicles with automatic transmission Installation position: as shown in Fig, arrow faces in direction of flow
13. Brake system vacuum pump -V192- For vehicles with automatic transmission
14. Fuel pressure regulator
15. Vacuum reservoir Location: In front left wheel housing beneath wheel housing liner
16. Vacuum actuator
17. Intake manifold change-over valve -N156

See also:
• READINESS CODE
• BATTERY DISCONNECT PRECAUTIONS
• CAMSHAFT POSITION (CMP) SENSOR, CHECKING
• SECONDARY AIR INJECTION (AIR) PUMP RELAY -J299- AND ACTIVATION, CHECKING
• EXHAUST MALFUNCTION INDICATOR LAMP (MIL) IN INSTRUMENT CLUSTER
• ACCELERATOR PEDAL MODULE WITH ACCELERATOR POSITION SENSOR, REMOVING AND INSTALLING
• BRAKELIGHT SWITCH
• DIAGNOSTIC TROUBLE CODE (DTC) MEMORY
• ADAPTATION
• LEFT 1/3 BACKREST, REMOVING AND INSTALLING
• LUGGAGE COMPARTMENT TRIM
• LUGGAGE COMPARTMENT SIDE TRIM, ASSEMBLY OVERVIEW
• SIDE LUGGAGE COMPARTMENT TRIM, ASSEMBLY OVERVIEW
• REAR SEAT BENCH, ASSEMBLY OVERVIEW
• SEATBENCH, REMOVING AND INSTALLING
• DRIVER-SIDE STORAGE COMPARTMENT (WITH AND WITHOUT KNEE BOLSTER), ASSEMBLY OVERVIEW
• OUTPUT DIAGNOSTIC TEST MODE (DTM)
• CRUISE CONTROL SYSTEM, ACTIVATING/DEACTIVATING
• FUEL TANK BREATHER, CHECKING
• MASS AIR FLOW (MAF) SENSOR -G70-, CHECKING
• LOCATIONS IN ELECTRONICS BOX (PLENUM CHAMBER)
• PROCEDURE FOLLOWING INTERRUPTION OF VOLTAGE SUPPLY
• ENGINE CONTROL MODULE (ECM) (WITHOUT METAL ANTI-THEFT HOUSING), REPLACING
• IDENTIFICATION OF CONNECTOR BRACKET - RIGHT SIDE OF VEHICLE
• OXYGEN SENSORS AND OXYGEN SENSOR CONTROL BEHIND CATALYTIC CONVERTER, CHECKING
• THROTTLE VALVE CONTROL MODULE -J338-, CHECKING
• THROTTLE VALVE CONTROL MODULE -J338-, ADAPTATION
• IDENTIFICATION OF CONNECTOR BRACKET - LEFT SIDE OF VEHICLE
• LOCATION OF THROTTLE POSITION (TP) SENSOR -G79- AND SENDER 2 FOR ACCELERATOR PEDAL POSITION -G185
• KICKDOWN FUNCTION, ADAPTING
• LOCATION OF FUEL PUMP (FP) RELAY -J17
• FUEL PUMP (FP) RELAY -J17- AND ACTIVATION, CHECKING
• LOCATION BRAKE LIGHT SWITCH -F- AND BRAKE PEDAL SWITCH (CRUISE CONTROL/DIESEL DIRECT FUEL INJECTION -F47-, CLUTCH VACUUM VENT VALVE SWITCH -F36
• MALFUNCTION LAMP FOR ELECTRONIC THROTTLE IN INSTRUMENT CLUSTER
• FUEL PRESSURE REGULATOR AND HOLDING PRESSURE (VEHICLES UP TO 06.03), CHECKING
• SYSTEM PRESSURE AND HOLDING PRESSURE (VEHICLES AS OF 07.03), CHECKING
• LOCATION OF INTAKE MANIFOLD CHANGE-OVER VALVE -N156
• INTAKE MANIFOLD CHANGE-OVER, CHECKING
• ENGINE CONTROL MODULE (ECM) (WITH METAL ANTI-THEFT HOUSING), REPLACING
• IF THE IDLING SPEED IS TOO HIGH OR TOO LOW AND THERE ARE NO DTCS RECORDED IN THE DTC MEMORY, PERFORM THE FOLLOWING TESTS MARKED WITH A DOT
• Significance of 5-digit readout of display group 056
• CHECKING FUEL PRESSURE REGULATOR - VEHICLES WITH FRONT WHEEL DRIVE (FWD)
• WIRING AND COMPONENT CHECK WITH TEST BOX VAG 1598/31
• LOOSENING AND TIGHTENING UNION NUT FOR FUEL SUPPLY LINE IN VEHICLES AS OF 07.03
• CHECKING ACTIVATION OF FUEL PUMP RELAY
• CHECKING VOLTAGE SUPPLY OF FUEL PUMP AND COMPONENTS
• COMPONENT LOCATIONS, OVERVIEW
• EVALUATION OF DISPLAY GROUP 002
• CHECKING WIRING TO MASS AIR FLOW (MAF) SENSOR
• CHECKING BASIC VOLTAGE
• CHECKING OXYGEN SENSOR LEARNED VALUES AND OXYGEN SENSOR CONTROL
• EVALUATING DISPLAY GROUP 032
• EVALUATING DISPLAY GROUP 033
• EVALUATION OF DISPLAY GROUPS 037 AND 038
• DATA EXCHANGE BETWEEN ENGINE CONTROL MODULE AND OTHER CAN-CONTROL MODULES, CHECKING
• ANGLE SENSOR FOR THROTTLE VALVE ACTUATOR, CHECKING
• CHECKING THE VOLTAGE SUPPLY TO THE THROTTLE VALVE CONTROL MODULE.
• Safety precautions