Knock Sensors, Checking
Knock Sensors, Checking
The following procedure is used to check Knock Sensor (KS) 1 G61 and Knock Sensor (KS) 2 G66.
Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram.
NOTE:
- Cylinders 1, 2, and 3 (bank 1) are monitored by Knock sensor (KS) 1 -G61-. Cylinders 4, 5, and 6 (bank 2) are monitored by Knock sensor (KS) 2 -G66-.
- Knock sensors themselves cannot be checked electrically.
- When servicing terminals in the harness connector of knock sensors, use only gold plated terminals.
- For the knock sensors to function properly, it is important that the tightening torque be exactly 20 Nm.
- Contact surfaces between Knock Sensor (KS) 1 G61 and Knock Sensor (KS) 2 G66 and cylinder block must be free of corrosion, dirt and grease.
Test requirements
- The mounting bolt of Knock Sensor (KS) 1 G61 / Knock Sensor (KS) 2 G66 tightened to 20 Nm.
- The Engine Control Module (ECM) J623 fuses OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- Vehicles with automatic transmission, shift selector lever into position "P" or "N".
- A/C switched off.
- Ground (GND) connections between engine/transmission/chassis OK.
- Ignition switched off.
Test procedure
- Perform a preliminary check to verify the customers complaint. General Diagnosis
Start diagnosis
- Remove the rear engine cover - arrows -.
Checking knock sensor and wiring
NOTE: The knock sensor electrical connectors can be identified by color. Knock Sensor (KS) 1 -G61- (Bank 1) is green. Knock Sensor (KS) 2 -G66- (Bank 2) is gray.
- Disconnect the electrical harness connector - 1 - or - 2 - of the respective knock sensor.
1 - Knock Sensor (KS) 1 -G61-..
2 - Knock sensor (KS) 2 -G66-..
Checking internal resistance
- Using a Multimeter , check the Knock Sensor terminals for an internal short.
Knock Sensor (KS) Electrical harness connector terminals
1 + 2
1 + 3
2 + 3
Specified value: (Infinity).
If the specified values are not obtained:
- Replace the faulty Knock Sensor (KS).
If the specified values are obtained:
Checking wiring
If the manufacturers test box is being used. Perform the following step.
- Install the test box.
If the manufacturers test box is not being used. Perform the following step.
- Remove the Engine Control Module (ECM) J623.
- Using a Multimeter , Check the Knock Sensor electrical harness connector to the Engine Control Module (ECM) J623 electrical harness connector T60 for an open circuit.
Knock Sensor (KS) 1 G61 Engine Control Module (ECM) electrical
electrical harness connector harness connector T60 terminals
terminals or test box sockets
1 41
2 58
3 42
Knock Sensor (KS) 2 G66 Engine Control Module (ECM) electrical
electrical harness connector harness connector T60 terminals
terminals or test box sockets
1 56
2 57
3 42
Specified value: 1.5 Ohms Max.
If the specified value was not obtained:
- Check the wiring connection for an open circuit, short circuit to Battery (+) or Ground (GND).
- Check the wiring connection for damage, corrosion, lose or broken terminals.
- If necessary, repair the faulty wiring connection.
If no malfunction is found in the wiring and the resistance was not OK:
- Replace the faulty Knock Sensor (KS).
If no malfunction is found in the wiring and the resistance was OK:
- Replace the Engine Control Module (ECM) J623.
Assembly is performed in the reverse order of removal, note the following:
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check the DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
- End diagnosis and switch ignition off.