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.
• 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. Refer to => [ General Diagnosis ] General Diagnosis.
Start diagnosis
- Remove the rear engine cover - arrows -.
Checking knock sensor and wiring
• 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.
Specified value: infinite (Infinity).
If the specified values are not obtained:
- Replace the faulty Knock Sensor (KS). Refer to Fuel Injection and Ignition Repair Information.
If the specified values are obtained:
Checking wiring
If the manufacturers test box is being used. Perform the following step.
- Install the test box. Refer to Fuel Injection and Ignition Repair Information.
If the manufacturers test box is not being used. Perform the following step.
- Remove the Engine Control Module (ECM) (J623 ). Refer to => [ ECM, Removing and Installing ] ECM, Removing and Installing.
- 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.
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). Refer to Fuel Injection and Ignition Repair Information.
If no malfunction is found in the wiring and the resistance was OK:
- Replace the Engine Control Module (ECM) (J623 ). Refer to => [ ECM, Removing and Installing ] ECM, Removing and Installing.
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 ] Diagnostic Mode 03 - Read DTC Memory.
2. If necessary, erase the DTC memory. => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.
3. If the DTC memory was erased, generate readiness code. => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.
- End diagnosis and switch ignition off.