Fuel Pump Driver Module

WARNING: This page is about a different car, the 2018 Land Rover Discovery and 2017 Land Rover Discovery. However, it is still accessible from the selected car via links, so may be relevant.

The Fuel Pump Driver Module (FPDM) regulates the flow and pressure supplied by controlling the operation of the fuel pump using a Pulse Width Modulation (PWM) output. A PWM signal from the Powertrain Control Module (PCM) tells the FPDM the required speed for the fuel pump. The on time of the PWM signal represents half the pump speed. For example, if the PWM signal with an on time of 50%, the FPDM drives the pump at 100%.

The FPDM will only energize the fuel pump if it receives a valid PWM signal, with an on time of between 4% and 50%. To switch the fuel pump off, the PCM transmits a PWM signal with an on time of 75%.

The output pressure from the fuel pump will change with changes of engine demand and fuel temperature. The PCM monitors the input from the fuel Low Pressure (LP) sensor and adjusts the speed of the fuel pump. The nominal output pressure is 5.5 bar (79.77 lbf/in² ) to 7.5 bar (108.77 lbf/in² ) absolute, during engine start up and engine shut down. Target pressure for the fuel low pressure delivery line is raised to 7.3 bar (105.88 lbf/in² ) absolute.

If the PCM does not detect pressure in the fuel delivery line, it stops, or refuses to start the engine and stores the appropriate Diagnostic Trouble Code (DTC).

The PCM receives a monitoring signal from the FPDM. Any DTCs produced by the FPDM are stored by the PCM.

DTCs can be retrieved from the PCM using an approved diagnostic system. The FPDM itself cannot be interrogated by the approved diagnostic system.

The FPDM is supplied power via a fuel pump relay in the Rear Junction Box (RJB). The fuel pump relay is controlled by the Body Control Module/Gateway Module (BCM/GWM) assembly. The fuel pump relay is active in all power modes, except power mode 0 (Ignition off). The PCM is connected to the BCM/GWM assembly to receive a 'wake-up' message and in the event of an accident the Restraints Control Module (RCM) outputs a crash signal to the BCM/GWM assembly to disable the fuel pump relay.