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
• ◆ Fault reader V.A.G 1551 (or vehicle system tester V.A.G 1552) with cable V.A.G 1551/3
• ◆ Adapter set V.A.G 1594
• ◆ Test box V.A.G 1598/22

• ‒ Connect fault reader V.A.G 1551
  .
• ‒ Switch on ignition.
• ‒ Interrogate fault memory.
• ‒ If a fault relating to the lambda probe is indicated on the display and the lambda probe heating is OK, unplug the lambda probe connector for the left-hand or right-hand cylinder bank.
  Fitting locations=>Pages 24-6.

• ‒ → 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 matches the specification, fit a new lambda probe.
• ‒ If the reading is not as specified, connect test box 1598/22 to the wiring harness for the engine control unit .

• ‒ → Test for open circuit and short to positive or earth in the following wiring connections:

Lambda probe Bank 1 -G39

Lambda probe Bank 2 -G108

• ‒ Rectify any open/short circuit as necessary.
• ‒ If the wiring is OK, fit a new engine control unit
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