Knock Sensor, Checking

KNOCK SENSOR, CHECKING

Special tools, testers and auxiliary items
- VAG 1598/18 test box
- Multimeter (Fluke 83 or equivalent)
- VW 1594 connector test kit
- Wiring diagram

Test sequence





- Disconnect brown 3-pin harness connector -2- from knock sensor 1 G61 socket -1-,
- Measure resistance between terminals 1 and 2, 1 and 3 and 2 and 3 at knock sensor connector socket.

Specification: Infinity Ohms (no continuity)

If the specification is attained:
- Connect VAG 1598/18 test box to ECM wiring harness.





- Check wiring between test box and 3-pin connector for open circuit according to wiring diagram.
- Terminal 1 and test box socket 34
- Terminal 2 and test box socket 33
- Terminal 3 and test box socket 56
- Wire resistance: Max. 1.5 Ohms
- Additionally check wires for short to one another.
- Terminal 3 and test box socket 34
- Terminal 3 and test box socket 33
- Terminal 2 and test box socket 34
- Specification: Infinity ohm (no continuity)

If no wiring malfunction is detected:
- Loosen knock sensor and tighten again to 20 Nm (15 ft lb).

If the malfunction is still present (stored again in DTC memory):
- Replace knock sensor.