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
When the ECM senses the ignition switch in the On, Crank or Run mode, battery positive voltage is supplied from the ASD relay and the PDC to the fuel pump relay. The ECM will also ground the fuel pump relay driver at this time, closing the fuel pump relay contacts, completing the fuel pump circuit to chassis ground. If the ECM senses the ignition in the ON position, without a engine crank signal for more than 30 seconds, it will open the fuel pump driver circuit, turning off the fuel pump.
The regulated fuel pump, in On and Crank mode will produce 0.4 to 1.5 bar (6 psi. to 22 psi.). In Run mode the fuel pump will produce at least 2.5 bar (36 psi.) not to exceed 2.9 bar (42 psi.) to maintain constant fuel pressure to the injection pump.
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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.