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.
Chart A1-7A, Fuel System CKT Opening Relay Check (PRIZM): Notes
When ignition switch is in START position, circuit opening relay will be energized to allow fuel pump to operate to pressurize system. Fuel pump will continue to operate if ECM receives an ignition signal when engine starts. Fuel pump operates as long as circuit opening relay is energized by ECM. When circuit opening relay is de-energized, fuel pump will stop operating.
- Checks for normal fuel pump operation.
- Checks if fuel pump will run when DLC terminals B+ and FP are jumpered together.
- Checks fuel pump operation while ignition signal is present at ECM.
- Checks for an open in Black/Red wire to circuit opening relay.
- Checks for an open in Black/Red wire to DLC.
- Checks for an open Blue/Black or Green/Red wire, a faulty ECM, or a faulty circuit opening relay.
- Checks for open White/Black or Blue/Black wire or faulty fuel pump.
Use the Manual With the Right Hardware
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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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