Knock Sensors G61 And G66, Checking
The following procedure is used to diagnose all Knock Sensors --.
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test requirements
- The mounting bolt of Knock Sensor (KS) 1 -G61- /Knock Sensor (KS) 2 -G66- tightened to 20 Nm.
- The Motronic Engine Control Module (ECM) - J220- 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 PRELIMINARY CHECK
Procedure
Before disconnecting the Knock Sensor -- electrical harness connectors, mark the component location.
-- Disconnect the Knock Sensor (KS) 1 -G61- electrical harness connector -1- or Knock Sensor (KS) 2 -G66- electrical harness connector -2-.
(APH Only)
(AWP, AWV Only)
Checking internal resistance
-- Using a Multimeter, check the Knock Sensor -- terminals 1 to 2 for an internal short.
Specified value: ∞ (Infinity).
If the specified value was not obtained:
-- Replace the faulty Knock Sensor (KS) 1 -G61- /Knock Sensor (KS) 2 -G66-.
If the specified value was 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 Motronic Engine Control Module (ECM) -J220-. Refer to MOTRONIC ENGINE CONTROL MODULE J220, REPLACING .
-- Using a Multimeter, Check the Knock Sensor -- electrical harness connector to the Motronic Engine Control Module (ECM) J220 electrical harness connector T121 for an open circuit.
(APH Only)
(AWP, AWV Only)
| Knock Sensor (KS) 1 -G61- electrical harness connector terminals | Motronic Engine Control Module (ECM) electrical harness connector T121 terminals or test box sockets |
|---|---|
| 1 | 106 |
| 2 | 99 |
| Knock Sensor (KS) 2 -G66- electrical harness connector terminals | Motronic Engine Control Module (ECM) electrical harness connector T121 terminals or test box sockets |
|---|---|
| 1 | 107 |
| 2 | 99 |
Specified value: 1.5 Ω 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, loose 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) 1 -G61- /Knock Sensor (KS) 2 -G66-.
-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY
-- Perform a road test to verify repair.
If the DTC does not return:
Repair complete, Generate readiness code. Refer to READINESS CODE .
-- End diagnosis.
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
-- Replace the Motronic Engine Control Module (ECM) -J220-. Refer to MOTRONIC ENGINE CONTROL MODULE J220, REPLACING .
-- Assembly is performed in the reverse of the removal.
-- Install the engine cover with air filter.
Final procedures
After the repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .
-- End of diagnosis.