Knock Sensor, Checking

Knock sensor, checking

NOTE:

- Knock sensor torque must be maintained at 20 Nm (75 ft lb) to ensure the knock sensors function correctly.
- Only gold-plated terminals may be used when servicing the knock sensor connector terminals.

Special tools, testers, measuring instruments and auxiliary items required

- VAG 1598/22 Test Box
- Fluke 83 multimeter
- VW 1594 Adaptor kit
- VAG 1527 B Voltage tester
- Wiring diagram

Test conditions

- On Board Diagnostic must have recognized a DTC for one or both knock sensors.

Checking function

- Functional check of knock control and knock sensors, Reading Measuring Value Blocks "Read measuring value block" display groups 14 to 16 and 24

Checking resistances and wiring

- Disconnect 3-pin harness connector (green) to knock sensor 1 G61 -1- and / or 3-pin connector (blue) to knock sensor 2 (G66) -2-.







- Measure resistance between the terminals 1 + 2, 1 + 3 and 2 + 3 at connections to knock sensors.

- Specification Infinity Ohms


- Connect test box VAG 1598/22 to Engine Control Module wiring harness.
- Check wiring for open circuit between Test Box and 3-pin harness connector using wiring diagram.






G61: G66:
Terminal 1 + socket 68 60
Terminal 2 + socket 67 67
Terminal 3 + socket 2 2

Wire resistance: Max. 1.5 Ohms

- Check wiring at socket 67 for short to sockets 60 and 68.
- Specification: Infinity Ohms

If wiring OK
- Loosen knock sensor and tighten again
- 20 Nm (15 ft lb) CRITICAL TORQUE

- Perform road test.

During road test following operating conditions must be fulfilled:
- Engine Coolant temperature must exceed 80 °C .
- After Engine Coolant Temperature is reached, the following operating conditions must be attained several times: Closed throttle (idle) Partial throttle Wide Open Throttle Overrun
- At Wide Open Throttle, engine speed must exceed 3500 rpm.
- Check ECM Diagnostic Trouble Code memory.

If knock sensor DTC still stored
- Replace knock sensor(s)