Glow Plug Control Module (GPCM) - Transit

The glow plug system consists of a GPCM, glow plugs, and the associated wiring harnesses. The glow plug on time is controlled by the GPCM and functions on the basis of the engine RPM, engine torque, engine coolant temperature, air temperature, BARO sensor and battery voltage. The GPCM is located behind the left hand side front wheel well cover near the firewall. The GPCM supplies voltage to the individual glow plugs, which it does by duty cycling direct battery voltage. Glow plug on time normally varies depending on battery voltage and the engine coolant temperature and ambient air temperatures. The voltage to the glow plugs is provided through the GPCM five high current drivers from the vehicle battery. Battery voltage is supplied to the GPCM, the power distribution box, then through the vehicle harness, which connects to the GPCM. The metallic instant start glow plugs can operate up to 8 minutes. The GPCM may activate the glow plugs during an extended idle at cold ambient temperatures. The GPCM provides battery voltage for approximately 2 seconds to heat the glow plugs, and then modulates the voltage to a lower setpoint to maintain optimal glow plug tip temperature. The GPCM monitors and detects individual glow plug functionality and control. Concerns detected by the GPCM are transmitted to the PCM over the controller area network 2 (CAN2) circuits.

Fig 1: GPCM (Transit)

Courtesy of FORD MOTOR CO.