Fuel Pump Relay

FUEL PUMP MODULE




The MS S52 controls the activation of the fuel pump module. After the ignition is switched ON the control module provides a pulse width modulated ground for the relay and the ground is maintained with the presence of the engine speed signal.

A new fuel pump is utilized to match the fuel supply demands of the S62 engine. While the pump delivers more volume and pressure, this creates more heat due to the increased power consumption. To lower the in-tank temperature, the fuel pump module will vary the pump speed (amperage). The MS S52 control module will vary the ground signal (PWM) to the fuel pump module.

This variation is based on engine speed and load:
- idle and part load low pump speed.
- start-up (20 seconds) and full-load full pump speed.

The power to the fuel pump relay will be switched off in the event of an airbag activation. The MRS III control module will signal the Engine control module over K-bus and CAN bus for this purpose.