Knock Sensor: Testing and Inspection

Knock Sensors, Checking

• For the knock sensors to function properly, it is important that tightening torque be exactly 20 Nm.

• Use only gold-plated terminals when servicing terminals in harness connector of knock sensors.

• Check harness connector from knock sensor to wiring harness for corrosion.

Component location of harness connectors.





1. 3-pin harness connector for Knock Sensor (KS) 1 (G61), cylinder bank 1

2. 3-pin harness connector for Knock Sensor (KS) 2 (G66), cylinder bank 2

Knock Sensors, Checking

- Disconnect the harness connector of the relevant knock sensor in engine compartment.

- Check all three terminals at respective knock sensor connector for short circuit to each other (terminal 1+2, 1+3, 2+3).





Specified value: Wires should have no connection to each other (infinite Ohm).

- If there is a connection, replace knock sensor.

- If wires have no connection to each other, check the wire connections.

Wires from Knock Sensors to ECM, Checking

- Connect test box (VAG1598/31) at wiring harness to Engine Control Module (ECM), do not connect ECM.

- Check wire connection from respective sensor coupling...





- ... to Engine Control Module (ECM) for wiring open circuit as well as short circuit to B+ and to Ground (GND).

Knock Sensors 1 G61, Bank 1





Knock Sensors 2G66, Bank 2





Wire resistance: max. 1.5 ohms

- Repair open circuit in wiring or short circuit if necessary.

If there is neither an open circuit in wiring nor a short circuit, replace Engine Control Module (ECM).

- Read readiness code => [ Readiness Code, Reading ] Monitors, Trips, Drive Cycles and Readiness Codes. If DTC memory was erased, readiness code must be generated again => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.