Audi Workshop Service and Repair Manuals

Notes:

• ◆ To test the operation of the knock sensors, use the function "Read measured value block", Display Groups 012, 013, 014 and 015.
• ◆ Fitting locations of plug connectors and knock sensors
  .
• ◆ It is not possible to carry out an electrical test of the knock sensors themselves. See "Interrogating fault memory", Page 01-7.
• ◆ In order to remove and install the knock sensors the intake manifold must be removed.
• ◆ To ensure that the knock sensors function properly it is important to keep exactly to the specified tightening torque of 20 Nm.
• ◆ Check connectors for corrosion.
• ◆ Use only gold-plated contacts when repairing the contacts in the plug connectors for the knock sensors.

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

Testing knock sensor wiring

• ‒ Unplug the connector for the relevant knock sensor in the engine compartment.

• ‒ → Test for short circuits between all three contacts in the knock sensor connector. 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 sensors to engine control unit

• ‒ Connect test box V.A.G 1598/22 to wiring harness for engine control unit
  => Page 24-24.
• ‒ Using the current flow diagram, test for continuity and short circuits in the wiring between the sender and engine control unit.

=> Current flow diagrams, Electrical fault-finding and Fitting locations

• → Identification of contacts in plug connector:

• ‒ Test continuity of signal wire of knock sensor 1 (-G61) from contact 1 on connector in engine compartment to socket 68 on test box.
• ‒ Specification: max. 1ω
• ‒ Test continuity of earth wire of knock sensor 1 (-G61) from contact 2 on connector in engine compartment to socket 67 on test box.
• ‒ Specification: max. 1ω
• ‒ Test continuity of screening on wiring for knock sensor 1 (-G61) from contact 3 on connector in engine compartment to socket 67 on test box.
• ‒ Specification: max. 1ω
• ‒ Test continuity of signal wire of knock sensor 2 (-G66) from contact 1 on connector in engine compartment to socket 60 on test box.
• ‒ Specification: max. 1ω

• ‒ Test continuity of earth wire of knock sensor 2 (-G66) from contact 2 on connector in engine compartment to socket 67 on test box.
• ‒ Specification: max. 1ω
• ‒ Test continuity of screening on wiring for knock sensor 2 (-G66) from contact 3 on connector in engine compartment to socket 67 on test box.
• ‒ Specification: max. 1ω
• ‒ If the values do not match the specifications, rectify the short circuits or open circuits.

• ● → Knock sensor 1

• ● Knock sensor 2