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Glow Plug: Description and Operation

ENGINE CONTROL COMPONENTS

Glow Plug
The glow plug improves ignition during cold engine starts by providing a heat source for combustion to improve cold engine starting and operation. The glow plugs are made of a resistive material that heats up when electricity flows through it. The glow plugs are duty cycle controlled by the glow plug control module (GPCM) and activated when modulated voltage is supplied to them. The ceramic instant start glow plugs can operate up to 20 minutes. The glow plugs may turn back on at cold ambient extended idle. The GPCM provides battery voltage for approximately 2 seconds to rush current and heat up the glow plugs, then drop back to 7 volts lowering the amperage. For additional information on glow plug system operation, refer to Powertrain Control Hardware Glow Plug Control Module (GPCM).