Positive Crankcase Ventilation Heating Element - N79-, Checking

General Description

The Positive Crankcase Ventilation Heating Element -N79- heats the positive crankcase ventilation valve, which allows the valve to quickly dissipate the crankcase gases into the intake manifold when the engine is below normal engine operating temperature.

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 automatic transmission, ensure the selector lever position is in "P".
Vehicles with manual transmission, ensure the shifter lever position is in "N" with the parking brake applied.
Observe all safety precautions: SAFETY PRECAUTIONS .
View clean working conditions: 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. -- NO: GATHER more information from customer about the complaint.
2	IGNITION: OFF. DISCONNECT: Positive Crankcase Ventilation Heating Element -N79- harness connector. CHECK: Positive Crankcase Ventilation Heating Element -N79- component connector terminals 1 to 2 for resistance. SPECIFIED VALUE: 2 - 4 Ω (@ 25° C). -- Was Value obtained?	-- YES: GO TO: Step 3. -- NO: REPLACE: Positive Crankcase Ventilation Heating Element -N79-. Refer to appropriate Service Information. GO TO: Step 5.
3	IGNITION: ON. CHECK: Positive Crankcase Ventilation Heating Element -N79- component connector terminal 2 to ground for voltage. IGNITION: OFF. SPECIFIED VALUE: Battery voltage. -- Was Value obtained?	-- YES: GO TO: Step 4. -- NO: PERFORM: Visual Inspection of wiring and component. 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 5.
4	REMOVE: Engine/Motor Control Module -J623-. Refer to appropriate Service Information. CHECK: Positive Crankcase Ventilation Heating Element -N79- harness connector terminal 1 to the Engine/Motor Control Module -J623- harness connector T56b / 44 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Was Value obtained?	-- YES: TIP: The Positive Crankcase Ventilation Heating Element -N79- may fail under loaded operation; please swap a known good Positive Crankcase Ventilation Heating Element -N79- prior to continuing to the next step. GO TO: Step 5. -- NO: PERFORM: Visual Inspection of wiring and component. 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 5.
5	Final Procedure Perform a road test to verify repair. -- Does the original DTC return?	-- YES: CHECK: Engine/Motor Control Module -J623- harness connector for any damaged, pushed-out pins. REPAIR: As necessary. If all electrical connections are OK: REPLACE: Engine/Motor Control Module -J623-. Refer to appropriate Service Information. Clear the DTC's. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY . Repair is complete. Generate Readiness Code. Refer to READINESS CODE . 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.