Check knock sensors

Disconnect harness connector of relevant knock sensor in engine compartment.

Fig 1: Disconnecting Harness Connector Of Relevant Knock Sensor In Engine Compartment

NOTE: Coolant reservoir screws must be removed and coolant reservoir must be placed to side in order to access harness connector for knock sensor for bank 2. The coolant hoses can remain connected.

Fig 2: Identifying Knock Sensor 3-Pin Connector Terminals

Check all three terminals at knock sensor connector for short circuit to each other (terminal 1+2, 1+3, 2+3).
- Specification: INFINITY Ω (no continuity) - the wires must not have any connection to each other.
If there is no connection, replace knock sensor.
If no short circuit is detected, check knock sensor wires:

Check wires from knock sensors to Engine Control Module (ECM) .

Connect VAG1598/31 test box at wiring harness to ECM; do not connect ECM. See WIRE AND COMPONENT TEST USING VAG1598/31 TEST BOX .
Check following wire connections for open circuit and short circuit to Ground (GND) and B+:

Fig 3: Identifying Knock Sensor 3-Pin Harness Connector Terminals

Knock Sensor (KS) 1 -G61-

KNOCK SENSOR (KS) 1 -G61- CIRCUIT TEST

Harness connector Terminal	VAG1598/31 test box Socket
1 (signal)	106
2 (Ground -GND-)	99
3 (shielding)	108

Fig 4: Identifying Knock Sensor 3-Pin Harness Connector Terminals

Knock Sensor (KS) 2 -G66-

KNOCK SENSOR (KS) 1 -G66- CIRCUIT TEST

Harness connector Terminal	VAG1598/31 test box Socket
1 (signal)	107
2 (Ground -GND-)	99
3 (shielding)	108

Repair open circuit or short circuit if necessary.