Audi Workshop Service and Repair Manuals

Note:

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

Special tools, testers and auxiliary items

• ◆ Hand multimeter V.A.G 1526 or V.A.G 1526 A
• ◆ Adapter set V.A.G 1594
• ◆ Test box V.A.G 1598/22

• ‒ Interrogate fault memory=>Page 01-7.

• ‒ If a fault in the lambda probe has been registered and the lambda probe heating is OK, unplug the lambda probe connector.
• ‒ → 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.
• ‒ Switch ignition on.

Specification: 450 ± 50 mV.

• ‒ If the reading is not as specified, connect test box 1598/22 to the wiring harness for the engine control unit =>Page 24-8.

• ‒ → Test the following wiring connections for open circuits or short circuits to positive or earth and rectify if necessary:

Lambda probe Bank 1 -G39

• ‒ If the wiring is OK, fit a new engine control unit
  =>Page 24-10.