Testing knock sensors — AUDI

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
=> Page
24-5
.
It is not possible to carry out an electrical test of the knock sensors themselves. The test is performed using the function "Interrogate fault memory"=>Page
01-7
.
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
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

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
24-8
.
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 binder

Identification of contacts in plug connector:

Signal wire · Earth wire · Screening
1 · 2 · 3

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. 1 ω.

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. 1 ω.

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. 1 ω.

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. 1 ω.

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. 1 ω.

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. 1 ω.

If the values do not match the specifications, rectify the short circuits or open circuits.

Knock sensor 1

Contact on connector / for sensor · Contact on control unit connector
1 (signal) / 2 (earth) / 3 (screening) · 68 / 67 / 67

Knock sensor 2

Contact on connector / for sensor · Contact on control unit connector
1 (signal) / 2 (earth) / 3 (screening) · 60 / 67 / 67