Recommended Procedure

Measure for continuity from the connector harness to the glow plug feed terminal on the Glow Plug Control Module (GPCM). Resistance should be less than 1 ohm. The glow plug system monitor will start when the glow plugs are commanded on for over 30 seconds and the battery voltage is between 10-14 volts. A glow plug DTC will be stored in continuous memory if one or more glow plugs are not functioning. Look very carefully for poor connections or loose fitting pins that will cause high resistance and set a DTC. The Glow Plug Monitor Self-Test is a KOER functional test of the glow plug system performed on demand with the engine running and the A/C off. The PCM will activate the GPCM which monitors the glow plug. The pedal may be used to increase the engine speed to increase voltage if needed. A fault must be present at the time of testing for the test to detect a fault. DTCs will be sent to the PCM on the diagnostic line and then output to the scan tool. The glow plug on time is dependent on engine oil temperature and altitude. The GPCM comes on between 1-120 seconds and does not come on at all if oil temperature is above 131°F (55°C). You can verify glow plug on time by monitoring the scan tool PIDs: EOT and GPCTM. The Wait To Start indicator ON time (1-10 seconds) is independent from GPCM ON time.