Fuel Pump Control Module / Fuel Pump
The fuel pump control module is called the PEM ( Pump Electronic Module ). Its function is to power the fuel pump and regulate the fuel pump power as necessary. When the pump's power changes, the fuel pressure/fuel flow is affected.
The control signal is based on an adaptation which compensates for component tolerances, ageing and wear. As the Engine Control Module (ECM) monitors the fuel pressure on the low pressure side, reconnection can occur and the control signal to the fuel pump control module can be adapted.
Even the actual fuel temperature is used to compensate the setpoint pressure and thus also the control signal.
The fuel pump control module is supplied with battery voltage by the fuel pump relay and grounded in the car body. The fuel pump relay is controlled by the Central Electronic Module (CEM) at the request of the Engine Control Module (ECM).
The engine cannot be started if the power supply to the fuel pump control module is faulty because the fuel pump will not then be powered.
The fuel pump control module is controlled by the Engine Control Module (ECM) via serial communication. The fuel pump control module then controls the fuel pump by adding PWM voltage to the fuel pump's ground lead.
There are no diagnostics for the fuel pump control module. The Engine Control Module (ECM) has diagnostics for fuel pressure regulation and the associated components.
The Pulse Width Modulated (PWM) signal from the Engine Control Module (ECM) to the fuel pump control module can be read off using the diagnostic tool.
The fuel pump control module is located on top of the fuel tank, on the left-hand front side.