Low Pressure Fuel Pump

WARNING: This page is about a different variant/trim than selected.

The Low Pressure (LP) fuel pump is controlled by the Fuel Pump Driver Module (FPDM) via the fuel pump relay located in the Rear Junction Box (RJB). Operation of the fuel pump relay is controlled by the Body Control Module/Gateway Module (BCM/GWM) using signals from the Powertrain Control Module (PCM). The PCM sends data to the FPDM via Pulse Width Modulation (PWM) signals to control LP fuel pump output.

The LP pump collects fuel from the swirl pot and passes it from the tank to the fuel delivery line via the intank fuel filter, to the engine mounted, HP (high pressure) pumps. The fuel is delivered at a pressure of 5.5 to 7.3 bar (79.9 to 105.9 Ibf/in.2) absolute.

Should the fuel pump electrical connection need to be disconnected, it is important that the ignition is switched off (power mode 0 or 4). If the ignition is on (power mode 6), the instrument cluster will store its last fuel gauge needle position prior to power down. Once power is restored the gauge will display the last stored position regardless of the actual level in the tank.

This could result in incorrect fuel gauge readings if the fuel tank has been drained and not filled with exactly the same quantity of fuel that was removed.