Audi Workshop Service and Repair Manuals

On ADP engines only one knock sensor is fitted (-G61).

Notes:

• ◆ It is not possible to carry out an electrical test of the knock sensors themselves.
• ◆ Interrogate fault memory .
• ◆ Read measured value block, Display groups 15 and 16
• ◆ To ensure that the knock sensors function properly it is important to keep exactly to the specified tightening torque of 20 Nm.
• ◆ Check plug connection from knock sensor to wiring harness for corrosion (plug connections are located behind the coolant expansion tank).

• ‒ Connect test box V.A.G 1598 with adapter cable V.A.G 1598/19 to the wiring harness for the Motronic control unit.
• ‒ Disconnect the plug for the relevant knock sensor (behind coolant expansion tank).

• ‒ → Check all three contacts on the knock sensor connector for short circuit to each other using an ohmmeter. The must be no connection between any of the wires.
• ‒ If there is a connection between the contacts, fit a new knock sensor.

Testing wiring from knock sensor to Motronic control unit

• ‒ Connect test box V.A.G 1598/19 to the wiring harness of the Motronic control unit.

• ‒ → Check wiring from the relevant sensor connector ...

• ‒ → ... to Motronic control unit -J220 for open circuit and short to positive or ground according to current flow diagram.

Note:

Use only gold plated contacts when repairing the contacts in the plug connectors for the knock sensors.