Redundant Fuel Pump Circuit Fault (A)
Indicates an issue with the redundant fuel pump circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
There are two fuel pumps, and one is acting up. This can cause fuel pressure issues, leading to performance problems.
What the computer is actually seeing
The engine control module (ECM) sees a drop in fuel rail pressure that doesn't match the expected levels due to a faulty fuel pump circuit. The circuit should allow around 50-60 PSI in a properly functioning system.
What a healthy reading looks like
Fuel rail pressure typically should be between 50-60 PSI when running, with an expected voltage of approximately 12-14 volts on the fuel pump circuits.
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 fuel pump circuit wiring for breaks or corrosion. Repair any faults found.
- 22. Inspect the fuel pump connector for corrosion and ensure it's making proper contact.
- 33. Verify fuel rail pressure with a gauge. Should be between 50-60 PSI under load.
- 44. If pressure is low, check fuel pump operation. Apply direct voltage to the pump to test functionality (should run).
- 55. If the pump runs but pressure is still low, check the fuel filter and fuel lines for blockages.
- 66. If everything else checks out, replace the fuel pump.
Common causes
- Faulty fuel pump
- Wiring issues
- Bad connector
- Fuel pressure regulator failure
- Sensor malfunction
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate. You might experience performance issues, so it's best to get it checked soon.
Will this code come back after clearing?
If the underlying issue isn’t fixed, yes, it will likely return.
Why does this code pair with SPN 1366?
SPN 1366 relates to the primary fuel pump circuit, so issues in both circuits can trigger both codes.
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