Knock Sensor 1 - G61-, Checking

General Description

The Knock Sensor 1 -G61- is a tuned accelerometer on the engine which converts engine vibration to an electrical signal. The Engine Control Module -J623- uses this signal to determine the presence of engine knock and to retard spark timing.

Special Tools And Workshop Equipment Required

Multimeter.
Wiring Diagram.
Scan Tool.

Test Requirements

Fuses OK.
Battery voltage OK.
Switch OFF all electrical and electronic accessories.
Vehicles with Auto. Transmission, ensure Selector Lever position is in "P".
Vehicles with Man. Transmission, ensure Shifter Lever position is in "N" with Parking Brake applied.
Observe all safety precautions: .
View clean working conditions: .

Test Procedure

Step	Procedure	Result / Action to Take
1	PERFORM: Preliminary Check to verify the customers concern. Refer to . -- Was Complaint verified?	-- YES: GO TO: Step 2 Knock Sensor 1 - G61-, CHECKING - 2 . -- NO: GATHER more information from customer about the complaint.
2	IGNITION: OFF. DISCONNECT: Knock Sensor 1 -G61- harness connector. CHECK: Knock Sensor 1 -G61- component connector terminals 1 to 2 for resistance. SPECIFIED VALUE: 2, 250 Ω (+/- 750 Ω @ approx. 20° C). -- Was Value obtained?	-- YES: GO TO: Step 3 Knock Sensor 1 - G61-, CHECKING - 3 . -- NO: REPLACE: Knock Sensor 1 -G61-. Refer to appropriate service information. GO TO: Step 4 Knock Sensor 1 - G61-, CHECKING - 4 .
3	REMOVE: Engine Control Module - J623-. Refer to appropriate service information. CHECK: Knock Sensor 1 -G61- harness connector terminal 1 to the Engine Control Module - J623- harness connector T105 / 98 for resistance. CHECK: Knock Sensor 1 -G61- harness connector terminal 2 to the Engine Control Module - J623- harness connector T105 / 97 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	-- YES: REPLACE: Knock Sensor 1 -G61-. Refer to appropriate service information. GO TO: Step 4 Knock Sensor 1 - G61-, CHECKING - 4 . -- NO: CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. REPLACE: Any open fuses. GO TO: Step 4 Knock Sensor 1 - G61-, CHECKING - 4 .
4	Final Procedure Perform a road test to verify repair. -- Does the original DTC return?	-- YES: CHECK: Engine Control Module -J623- harness connector for any damaged, pushed-out pins. REPAIR: As necessary. If all electrical connections are OK: REPLACE: Engine Control Module -J623-. Refer to appropriate service information. Clear the DTC's. Refer to . Repair is complete. Generate Readiness Code. Refer to . Return vehicle to Customer. -- NO: Perform the diagnostic procedure for any DTC's. If no DTC's return the repair is complete. Return vehicle to customer.