Fuel Pump Driver Module (FPDM)
The fuel pump driver module (FPDM) is located on a bracket which is integral with the charcoal canister. The module is attached to one end of the canister with a bracket.
The fuel pump operation is regulated by a fuel pump driver module (FPDM) which is controlled by the engine control module (ECM). 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.
The fuel pump driver module (FPDM) is powered by a supply from the fuel pump relay in the rear junction box (RJB). The fuel pump relay is energized on opening the driver's door, pressing the start button only or pressing the start button and the footbrake (which initiates engine cranking). The fuel pump driver module (FPDM) supplies power to the fuel pump, and adjusts the power to control the speed of the fuel pump and thus the pressure and flow in the fuel delivery line.
A pulse width modulation (PWM) signal from the engine control module (ECM) tells the fuel pump driver module (FPDM) the required speed for the fuel pump. The on time of the pulse width modulation (PWM) signal represents half the fuel pump speed, e.g. if the pulse width modulation (PWM) signal has an on time of 50%, the fuel pump driver module (FPDM) drives the pump at 100%.
The fuel pump driver module (FPDM) will only energize the fuel pump if it receives a valid pulse width modulation (PWM) signal, with an on time of between 4% and 50%. To switch the fuel pump off, the engine control module (ECM) transmits a pulse width modulation (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 engine control module (ECM) monitors the input from the fuel rail LP sensor and adjusts the speed of the fuel pump as necessary to maintain a nominal output pressure of 450 kPa (4.5 bar; 65.3 lbf/in.2 ), except during engine start-up. At engine start-up the target pressure for the fuel delivery line is 630 kPa (6.3 bar; 91.4 lbf/in.2 ).
If the supplemental restraint system (SRS) outputs a crash signal on the high speed controller area network (CAN), the engine control module (ECM) de-energizes the fuel pump relay to prevent any further fuel being pumped to the engine.
If the engine control module (ECM) 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 engine control module (ECM) receives a monitoring signal from the fuel pump driver module (FPDM). Any diagnostic trouble code (DTC)'s produced by the fuel pump driver module (FPDM) are stored by the engine control module (ECM).
diagnostic trouble code (DTC)'s can be retrieved from the engine control module (ECM) using an approved Jaguar diagnostic system. The fuel pump driver module (FPDM) itself cannot be interrogated by the approved Jaguar diagnostic system.