Glow Plugs, Checking

Glow Plugs, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Diode test lamp.

• Wiring diagram.

Test requirements

• Fuse (S39) OK.

• The Glow Plug Relay (J52) OK.

• Battery voltage at least 12.5 volts.

• 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 ] Preliminary Check.

Start diagnosis

- Disconnect the Engine Coolant Temperature (ECT) Sensor (G62) electrical harness connector - 1 -.





• A "cold engine" condition is simulated when the ECT electrical harness connector is disconnected and the ignition is switched on for the appropriate glow period.

Checking voltage supply

- Disconnect the Glow Plug electrical connectors.

- Using a Multimeter, check each Glow Plug electrical connector, in sequence, from 1 to 4, to Ground (GND) for voltage.

Specified value: Battery voltage for 20 seconds.

If the specified value is not obtained:

- Using a Multimeter, check each Glow Plug electrical harness to the Glow Plug Relay (J52) socket 4 & 6 for resistance.

Specified value: 1.5 ohms Max.

If the specification was not obtained:

- Check the wiring from the Glow Plug electrical harness to the Glow Plug Relay (J52) socket 4 & 6 for an open circuit, short circuit to each other or to Battery (+) or Ground (GND).

- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring and the voltage supply was not OK:

- Check the Glow Plug Relay (J52). Refer to => [ Glow Plug Relay, Checking ] Glow Plug Relay, Checking.

If no malfunction is detected in the wiring and the voltage supply was OK:

Checking Glow Plug

- Using a Diode test lamp, check the Glow Plug from Battery (+) to each individual Glow Plug.





The Diode test lamp must light up.

If the Diode test lamp does not light up:

- Replace the faulty Glow Plug.

- Perform a road test to verify repair.

If the fault does not return:

Repair complete, Generate readiness code. Refer to => [ Readiness Code ] Readiness Code.

- End diagnosis.

If the fault does return and no malfunction is detected in the wiring and the voltage supply was OK:

- Recheck the voltage supply.

- Assembly is performed in the reverse of the removal.

Final procedures

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Readiness Code.

End diagnosis.