Knock Sensor, Checking

Special tools and equipment
- VAG 1598/18 Test Box
- Fluke 83 multimeter (or equivalent)
- VW 1594 Adapter kit
- Wiring diagram

Test sequence
- Remove insulation tray.







- Connect VAG 1598/18 Test Box ECM wiring harness.
Knock sensor 1 -G61-







- Disconnect white 3-pin harness connector to knock sensor 1 (arrow).

Knock sensor 2 -G66-







- Disconnect black 3-pin harness connector to knock sensor 2 (arrow).
- Switch multimeter to resistance range.







- Measure resistance between knock sensor terminals, connecting as follows:
between terminals 1 + 2
between terminals 1 + 3
between terminals 2 + 3
- specification: infinity Ohms







- Check for open circuit between Test Box and 3-pin harness connector using wiring diagram, connecting as follows:

-G61- -G66-
terminal 1 + socket 34 57
terminal 2 + socket 33 33
terminal 3 + socket 56 56
- wire resistance: 1.5 Ohms maximum

- Check wires for shorting to one another;

-G61- -G66-
terminal 2 + socket 34 57
terminal 3 + socket 33 33
terminal 3 + socket 34 57

- specification: infinity Ohms

If wiring OK:
- Loosen appropriate knock sensor and re-torque.
Tightening torque: 20 Nm (15 ft lb)
- Road test vehicle. During road test, engine coolant temperature must exceed 80 °C.

When the above temperature is reached, the following operating conditions must be attained several times:
- Closed throttle
- Partially open throttle
- Wide open throttle
- Overrun
- At wide open throttle, engine rpm must exceed 3500

- Check DTC memory.

If DTC is still present in DTC memory:
- Replace appropriate knock sensor, G61 and/or G66.
- Read-out Readiness code. Refer to Monitors, Trip and/or Drive Cycle (Readiness Codes)/Readiness Code Checking. Testing and Inspection

If DTC memory has been erased:
- Create Readiness code. Refer to Monitors, Trip and/or Drive Cycle (Readiness Codes)/Readiness Code Generating Testing and Inspection