Fuel Pump Secondary Circuit Malfunction
The engine control module (ECM) detected a problem with the fuel pump secondary circuit.
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What it means (plain English)
The computer notices something is wrong with the backup circuit for the fuel pump, which helps deliver gas to the engine.
What the computer is actually seeing
The ECM sees an abnormal voltage or resistance reading from the fuel pump secondary circuit, typically expecting around 12V when the pump is activated.
What a healthy reading looks like
Expected voltage at the fuel pump connector: 12V with ignition on, around 0-1Ω resistance for a good wire connection.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the battery voltage, ensure it's above 12.4V.
- 22. Inspect the fuel pump relay and swap it with a similar relay if available - if the code clears, the relay was bad.
- 33. Check the wiring from the fuel pump to the ECM for damage or loose connections. Repair as necessary and retest.
- 44. Test the resistance of the fuel pump circuit; it should be close to 0-1Ω. If it reads significantly higher, isolate and repair as needed.
- 55. Verify fuel pump operation by connecting a fuel pressure gauge; expected pressure should be within manufacturer's spec (usually 40-60 PSI).
Common causes
- Faulty secondary fuel pump relay
- Damaged wiring or connectors in the fuel pump circuit
- Low fuel pressure due to pump failure
- Faulty fuel pump
- Blown fuse in the fuel pump circuit
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive the vehicle with this code?
It's not recommended since it can cause fuel delivery issues, leading to stalling or no-start.
Will this code come back after clearing?
It may return if the underlying issue isn't fixed, especially if the relay or wiring is bad.
Why does this code pair with other fuel-related codes?
They often share the same circuit components, so issues can affect multiple diagnostics.
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