Audi Workshop Service and Repair Manuals

Note for engine code AEB:

The lambda probe heating circuit is monitored by the self-diagnosis system.

• ‒ Interrogate fault memory =>Page 01-8.
• ‒ Unplug connector for lambda probe
• ‒ → Use V.A.G 1526 to test continuity (resistance measurement) between contacts 1 and 2 on lambda probe connector.

Note:

The resistance of the heating element is about 1...5 ωat room temperature. Even with a small temperature increase the resistance rises sharply.

• ‒ If an open circuit is detected, fit a new lambda probe.

• ‒ If the heating element has continuity, test the power supply for the lambda probe heating as follows:
• ‒ Test fuse 29.

• ‒ → If the fuse is OK, connect diode test lamp V.A.G 1527 between contact 1 of the connector on the wiring harness and engine ground.
• ‒ Operate the starter briefly (the engine may also start briefly). The diode test lamp should light up.
• ‒ → If the diode test lamp does not light up, test wiring from contact 1 on connector on wiring harness to fuse for open circuit or short to ground. Rectify if necessary.
• ‒ If the fuse and the wiring are OK, but the diode test lamp still fails to light up, test the fuel pump relay =>Page 24-31.

• ‒ If the voltage supply is OK, connect test box V.A.G 1598/19 to the wiring harness for the Motronic control unit.

Engine code AEB only:

• ‒ → Check the wiring from contact 2 of the connector on the wiring harness (ground wire) to socket B7 on the test box for an open circuit or short circuit to positive or ground.

• ‒ → If necessary repair open circuit between contact 2 of the connector on the wiring harness and contact B7.

Engine codes ADP and ADR only:

• ‒ → Check wiring from contact 2 of the connector in the wiring harness (ground wire) to engine ground for continuity, if necessary eliminate open circuit.