Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Fuel Pump Module
The MS S52 controls the activation of the fuel pump module. After the ignition is switched ON, the MS S52 provides a pulse width modulated ground for the fuel pump module and the ground is maintained with the presence of the engine speed signal.
While new fuel 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.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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