2007 Audi A4 (B7) Service & Repair Manual

01 ON BOARD DIAGNOSTIC (OBD) ON BOARD DIAGNOSTIC (OBD) On Board Diagnostic (OBD), technical data Equipment  Data is transmitted between the control module and the VAS5051 tester via operating mode "On Board Diagnostic (OBD)".  DTC memory is designed for permanent memory and is therefore not dependent on voltage supply.  Display of stored DTCs occurs after initiation of display mode. Refer to Diagnostic Trouble Code (DTC) memory, checking .  DTC memory must be erased after malfunction is repaired. Refer to Diagnostic Trouble Code (DTC) memory, erasing . Important:  Readiness code must be generated every time DTC memory is erased. Refer to Readiness code, generating .  If the ECM recognizes malfunctions that lead to a worsening of emissions values, it indicates them by lighting the Malfunction Indicator Lamp (MIL) -K83- in the instrument cluster. Meaning of exhaust Malfunction Indicator Lamp (MIL) -K83-. Refer to Exhaust Malfunction Indicator Lamp (MIL) in instrument cluster .  EPC relevant malfunctions are also indicated by the Electronic Power Control (EPC) warning lamp in the instrument cluster. Exhaust Malfunction Indicator Lamp (MIL) in instrument cluster If the ECM recognizes malfunctions that lead to a worsening of emissions values, it indicates them by lighting the exhaust Malfunction Indicator Lamp (MIL). The Engine Control Module (ECM) switches on the exhaust Malfunction Indicator Lamp (MIL) after ignition is switched on. Shortly after engine is started, the exhaust MIL will go out. This requires, first of all, that the Engine Control Module (ECM) does not detect a malfunction that worsens the emissions values and, secondly, that activation of the lamp by the Engine Control Module (ECM) is OK. If malfunctions that worsen emissions are recognized during operation of the engine, the ECM switches on the exhaust MIL in instrument cluster. An entry is made in DTC memory at the same time. The Malfunction Indicator Lamp (MIL) can blink or remain lit continuously. DTC memory should be checked in either case. Refer to Diagnostic Trouble Code (DTC) memory, checking . Continuously lit: There is a malfunction that causes increased emissions. Check DTC memory for Motronic ECM and automatic 2005 Audi A4 Quattro ENGINE PERFORMANCE 3.0 Liter 6-Cyl. 5V Fuel Injection & Ignition, Engine Code(s): AVK, BGN 2005 Audi A4 Quattro ENGINE PERFORMANCE 3.0 Liter 6-Cyl. 5V Fuel Injection & Ignition, Engine Code(s): AVK, BGN 12:18:17 AM Page 1 12:18:29 AM Page 1

transmission (if installed). Check DTC memory if there is a drivability problem or a customer complaint, but the exhaust Malfunction Indicator Lamp (MIL) is not lit. There may be DTCs stored that do not cause the exhaust MIL to light up immediately, but only after engine is started again and malfunction is recognized again. Blinking: There is a malfunction that causes damage to the catalytic converter in this driving condition (e.g. combustion misfire). In this case, vehicle must only be driven at reduced power! Exhaust Malfunction Indicator Lamp (MIL), checking Function test of warning lamp  Switch ignition on.  Warning lamp for On Board Diagnostic (Malfunction Indicator Lamp -MIL-) must light up  Start engine.  Shortly after engine is started, the Malfunction Indicator Lamp (MIL) will go out if there are no malfunctions stored in the DTC memory that relate to the emissions system Safety precautions Vehicle diagnostic, testing and information system VAS5051, connecting and select functions Test requirements  Fuses for engine electronics OK NOTE: The switch-on signal for the Malfunction Indicator Lamp (MIL) is transferred from the Engine Control Module (ECM) to the instrument cluster via CAN-bus. Check data exchange between the Engine Control Module (ECM) and other CAN capable control modules. Refer to Data exchange between engine control module and other CAN - control modules, checking NOTE: The following points if testers and measuring instruments have to be used during a road test: WARNING:  Always install testers and measuring instruments on the back seat and have a second person operate them from there.  If test equipment were operated from the front passenger seat, the person sitting there could be injured if the front passenger airbag were triggered in the event of an accident. 2005 Audi A4 Quattro ENGINE PERFORMANCE 3.0 Liter 6-Cyl. 5V Fuel Injection & Ignition, Engine Code(s): AVK, BGN 12:18:17 AM Page 2

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations  Battery voltage at least 12.7 V  Ground connections on engine and transmission OK. Procedure  Switch ignition off. Fig. 1: Identifying Vehicle Diagnosis, Testing and Information System VAS 5051 and Data Link Connector (DLC) Courtesy of VOLKSWAGEN UNITED STATES, INC.  Connect up vehicle diagnostic, testing and information system VAS5051 with diagnostic wire VAS5051/1. Refer to Operating instructions of vehicle diagnostic, testing and information system VAS5051 WARNING: Note the safety precautions. Refer to Safety precautions NOTE: A DTC message appears on the display: 2005 Audi A4 Quattro ENGINE PERFORMANCE 3.0 Liter 6-Cyl. 5V Fuel Injection & Ignition, Engine Code(s): AVK, BGN 12:18:17 AM Page 3

Fig. 2: Diagnostic System VAS 5051: Display Courtesy of VOLKSWAGEN UNITED STATES, INC. Display on VAS5051:  Press "vehicle self-diagnosis" button. Fig. 3: Diagnostic System VAS 5051: Display Courtesy of VOLKSWAGEN UNITED STATES, INC. Display on VAS5051: NOTE: The automatic test sequence is carried out by pressing "00 - Check Diagnostic Trouble Code (DTC) memory - Total system" in selection -1-, i.e. the DTC memories of all vehicle systems with On Board Diagnostic (OBD) capability are checked. 2005 Audi A4 Quattro ENGINE PERFORMANCE 3.0 Liter 6-Cyl. 5V Fuel Injection & Ignition, Engine Code(s): AVK, BGN 12:18:17 AM Page 4

Fig. 4: Diagnostic System VAS 5051: Display Courtesy of VOLKSWAGEN UNITED STATES, INC. Display on VAS5051: Depending on which function is required "Diagnostic functions" table: Refer to Vehicle diagnostic, testing and information system VAS5051, connecting and select functions :  Switch ignition on. or  Start engine.  Select vehicle system "01 - Engine electronics" in selection -1-.  Wait until next display appears. Fig. 5: VAS 5051 Tester Displaying Control Module Identification And Coding Courtesy of VOLKSWAGEN UNITED STATES, INC. Display on VAS5051: 1 - Control module identification of engine control module. Refer to Vehicle diagnostic, testing and information system VAS5051, connecting and select functions 2005 Audi A4 Quattro ENGINE PERFORMANCE 3.0 Liter 6-Cyl. 5V Fuel Injection & Ignition, Engine Code(s): AVK, BGN 12:18:17 AM Page 5

2007 Audi A4 (B7) Service & Repair Manual

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