Audi Workshop Service and Repair Manuals

Note:

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

• ‒ Interrogate fault memory .
• ‒ If a fault in the lambda probe has been registered and the lambda probe heating is OK, unplug the lambda probe connector.

• ‒ Switch the ignition on.
• ‒ → Test voltage by connecting hand held multimeter V.A.G 1526 (measuring range 2 V) between contacts 3 and 4 of plug on wiring harness.

Specification: approx. 1.56 V.

• ‒ If the reading is not as specified, connect test box 1598/22 to the wiring harness for the engine control unit .

• ‒ → Test the following wiring connections for open circuits and shorts to positive or earth; if necessary, rectify the fault.

Lambda probe Bank 1 -G39

• ‒ If the wiring is OK, fit a new engine control unit .