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.
Circuit Description
When ECM receives reference pulses from the CKP sensor, ECM enables the fuel pump relay by grounding the driver. When ECM is commanding this relay on, control circuit voltage should be low (near zero volts). When ECM is commanding this relay off, control circuit voltage should be high (about battery circuit). DTC will set when the fault detection circuit in ECM does not see a signal for an extended period of time.
DTC will also set when fuel pump circuit is open and following conditions exist:
- Battery voltage between 7.5-15.0 volts.
- Engine speed greater than 40 RPM.
NO RELATED
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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.