Fuel Pump Control Module (FPCM)

The fuel pump flow control module (FPCM) is a serviceable GMLAN device mounted on the left, rear corner under the rear compartment floor panel carpet of the vehicle. The FPCM receives the desired fuel pressure message from the engine control module (ECM) and drives the FPCM relay to control the 3-phase fuel pump, located within the fuel tank, to achieve the desired fuel pressure. A liquid pressure sensor provides fuel pressure feedback to the FPCM.

The FPCM provides a control enable input to the FPCM relay to turn the 3-phase fuel pump ON and OFF. The control enable input is switched to ground to turn ON the pump. The FPCM also sends a 400 HZ pulse width module (PWM) signal to the FPCM relay to control the fuel pump speed by varying the duty cycle of this signal.