Knock Sensors, Checking

Knock Sensors, Checking







Special tools and workshop equipment required
- V.A.G 1526 A Multimeter
- V.A.G 1594 A Connector test kit
- V.A.G 1598/31 Test box

NOTE:
- The Knock sensors -G61- and -G66- cannot be tested electrically by themselves..
- Use only gold-plated terminals when repairing the cable connectors for the knock sensors.
- To ensure that the knock sensors function properly it is important to keep exactly to the specified tightening torque of 20 Nm.
- Check connector between knock sensor and wiring harness for corrosion.

Checking knock sensor wiring







- Disconnect Knock sensor 1 -G61- connector -Pos. 1- or Knock sensor 2 -G66- connector -Pos. 4-.







NOTE: To gain access to the connector, remove coolant expansion tank bolt (arrow) and move expansion tank to the side. Fuel hoses remain connected.







- Test for short between all three terminals in knock sensor connector (terminals 1+2, 1+3, 2+3).
- Specified value: infinity ohm (no continuity) wiring must not be connected to each other.
- If there is a connection between terminals, install a new knock sensor.

If no malfunction is found:

Checking wiring from knock sensors to ECM
- Connect test box V.A.G 1598/31 to wiring harness for ECM; do not connect ECM.
- Check for open circuit, short to ground, or short to positive in following wiring connections:







- Knock sensor 1 -G61- (cylinders 1 and 2)

Connector Test box V.A.G 1598/31
terminal Socket
1 (signal) 106
2 (ground) 99
3 (screening) 108







- Knock sensor 2 -G66- (cylinders 3 and 4)

Connector Test box V.A.G 1598/31
terminal Socket
1 (signal) 107
2 (ground) 99
3 (screening) 108

- Repair any open/short circuit as necessary.