Positive Crankcase Ventilation (PCV) Heating Element Checking
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test requirements
- The Engine Control Module (ECM) - J623- fuses OK.
- The Power Supply Relay (terminal 50) -J682- 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 connections between engine/transmission/chassis OK.
- Ignition switched OFF.
- Engine cold.
Test procedure
-- Observe safety precautions. Refer to SAFETY PRECAUTIONS
-- Observe Clean Working Conditions. Refer to CLEAN WORKING CONDITIONS
-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK .
Checking internal resistance
-- Disconnect the Positive Crankcase Ventilation (PCV) Heating Element -N79- electrical harness connector -2-.
-- Using a multimeter, check the Positive Crankcase Ventilation (PCV) Heating Element -N79- terminals 1 to 2 for resistance.
Specified value: 7 to 12 Ω (at approx. 20° C)
If the specified value was Not obtained:
-- Replace the Positive Crankcase Ventilation (PCV) Heating Element -N79-. Refer to the Repair Information.
If the specified value was obtained:
Checking voltage
Switch the ignition ON.
-- Using a multimeter, check the Positive Crankcase Ventilation (PCV) Heating Element -N79- electrical connector terminal 1 to ground for voltage.
Specified value: Battery voltage.
Switch the ignition OFF.
If the specified value was Not obtained:
-- Check the wiring from the Positive Crankcase Ventilation (PCV) Heating Element -N79- electrical connector terminal 1 to fuse 50 in Fuse Panel B for high resistance, a short circuit to ground or an open circuit.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the wiring connection.
If the specified value was obtained:
Checking Ground
-- Using a multimeter, check the Positive Crankcase Ventilation (PCV) Heating Element -N79- electrical connector terminal 2 to ground for resistance.
Specified value: 1.5 Ω Max.
If the specification was Not obtained:
-- Check the wiring for an open, high resistance or short circuit to voltage or ground.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
Final procedures
After repair work, the following work steps must be performed in the mentioned 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 .