Operation CHARM: Car repair manuals for everyone.

General Information

The glow plug system provides the heat needed to begin combustion when starting the engine at cold ambient temperatures.

The glow plug relay switches power to the glow plugs and is commanded ON and OFF by the PCM. The glow plugs are heated before and during cranking, as well as during the initial engine operation. The PCM monitors glow plug relay output voltage in order to determine if the relay is following the PCM commands.