11. Glow Plug System Operation

11. Glow Plug System Operation

Note: Glow plug on time is dependent on oil temperature and altitude. The GPCM commands the glow plugs on for 1 to 120 seconds. The GPCM does not operate if the oil temperature is above 55°C (131°F).

Purpose:

The purpose of this test is to verify the glow plug system operation.

Glow Plug Control Module (GPCM) Operation

^ Connect the scan tool.
^ Retrieve the KOEO and continuous DTCs. If GPCM DTCs are present GO to Pinpoint Test AF.
^ Verify battery voltage is supplied to the GPCM.

Note: The wait to start indicator on time (1-10 seconds) is independent from glow plug on time.

^ Monitor the GPCTM and EOT PIDS to verify sufficient glow plug ON time.
^ Key ON engine OFF.
^ Measure the glow plug voltage ON time.






Glow Plug Resistance

Note: Check for incorrect connections or loose fitting pins.

Note: Incorrect measurements result if all glow plug connectors are not disconnected.

^ Disconnect the glow plug bus bar connector.
^ Measure the resistance between the glow plug bus bar connector component side and battery ground.
^ Disconnect the GPCM.
^ Measure the resistance between the GPCM connector harness side and the glow plug bus bar connector~ harness side.






Recommended Procedure:

The glow plug monitor self-test is a KOER functional test of the glow plug system. The self-test is carried out on-demand with the engine running and the A/C off. The PCM will activate the GPCM which monitors the glow plugs. The accelerator pedal may be used to increase the engine speed to increase voltage if needed. For fault detection the self-test requires a concern present at the time of testing.






Possible Causes:

^ GPCM power circuits
^ Glow plugs
^ Glow plug bus bar
^ GPCM
^ Circuitry

Tools Required:

^ 23 Multimeter 105-00050 or equivalent. Input impedance 10 megohm minimum.
^ Scan tool