Engine Speed Sensor -G28-, CHECKING

Function

The Engine Speed Sensor -G28- detects rpm and reference marks from a toothed wheel on the crankshaft. Without an engine speed signal, the engine will not start. If the engine speed signal fails while the engine is running, the engine will stop immediately.

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 Manual Transmission, ensure Gear Shift Lever position is in "N" with Parking Brake applied.
Coolant Temperature: ≥ 80° C.
Observe all safety precautions. Refer to: SAFETY PRECAUTIONS .
View clean working conditions. Refer to: CLEAN WORKING CONDITIONS .

Test Procedure

Step	Procedure	Result / Action to Take
1	PERFORM: Preliminary Check to verify the customers complaint. Refer to: PRELIMINARY CHECK . -- Was Complaint verified?	-- YES: GO TO Step 2 Engine Speed Sensor -G28-, CHECKING . -- NO: GATHER more information from customer about the complaint.
2	IGNITION: OFF. DISCONNECT: Engine Speed Sensor -G28- harness connector. CHECK: Engine Speed Sensor -G28- component connector terminals 2 to 3 for resistance. SPECIFIED VALUE: 450 Ω (+/- 500 Ω @ approx. 20° C). IGNITION: OFF. -- Was Value obtained?	-- YES: GO TO Step 3 Engine Speed Sensor -G28-, CHECKING . -- NO: REPLACE: Engine Speed Sensor -G28-. Refer to appropriate repair service information. GO TO: Step 4 Engine Speed Sensor -G28-, CHECKING .
3	REMOVE: Engine Control Module - J623-. Refer to appropriate repair service information. CHECK: Engine Speed Sensor -G28- harness connector terminal 1 to the Engine Control Module - J623- harness connector T60 / 50 for resistance. CHECK: Engine Speed Sensor -G28- harness connector terminal 2 to the Engine Control Module - J623- harness connector T60 / 36 for resistance. CHECK: Engine Speed Sensor -G28- harness connector terminal 3 to the Engine Control Module - J623- harness connector T60 / 51 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Were Values obtained?	-- YES: REPLACE Engine Control Module -J623-. Refer to appropriate repair service information. GO TO: Step 4 Engine Speed Sensor -G28-, CHECKING . -- NO: CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 4 Engine Speed Sensor -G28-, CHECKING .
4	Final Procedure Perform a road test to verify repair. Do any DTC's return:	-- YES: Check the DTC memory. Refer to: DIAGNOSTIC MODE 03 - READ DTC MEMORY . Perform the diagnostic procedure for that DTC. -- NO: Repair is complete. Generate readiness code. Refer to: READINESS CODE . Return vehicle to Customer.