Pinpoint Test AF: Glow Plug System: Introduction: Description

The glow plug system is composed of a solid state glow plug control module (GPCM) and the glow plugs. The GPCM provides direct battery voltage to the glow plugs. The GPCM monitors the individual glow plug operation. Faults detected by the GPCM are transmitted to the PCM using a serial communication signal on a diagnostic line.

The powertrain control module (PCM) enables and controls the GPCM. The glow plug ON time is a function of oil temperature, barometric pressure, and battery voltage. The ON time normally varies between 1 to 120 seconds and is limited by the GPCM to 180 seconds regardless of PCM commands.