Fuel Pump: Description and Operation

Fuel Supply, Low-pressure Side

Electric fuel pump

NOTE: The electric fuel pump must be operated only with the electric control unit.

The delivery rate is regulated by the speed of the electric fuel pump by way of the specified frequency (with limitation of the phase current).

Control







NOTE: Further diagnostic information on the PWM signal and diagnosis is described in Guided Fault Finding.

The output of the fuel pump is controlled by the DME control unit by a PWM control signal. This bidirectional PWM interface is also used for diagnosis of the control unit for the electric fuel pump. The speed of the electric fuel pump is regulated by means of the specified frequency within the power limits of the fuel pump (with limitation of the phase current) and independently of the vehicle electrical system voltage (voltage compensation). The pump motor is a brush-less three-phase synchronous motor.