Glow Plugs - PCM-Controlled
The glow plugs are located in the cylinder heads, under the glow plug buss bar.
The glow plugs are self-regulating. If the engine oil temperature is above 55 °C (131 °F), the PCM will bulb-check the WAIT TO START lamp but not energize the glow plug relay.
The glow plug ON time varies from 0-120 seconds depending on battery voltage, engine oil temperature and barometric pressure.
The glow plug control monitor (GPCM) system is designed to find failed glow plugs or failed wiring in the glow plug system.