Low Fuel Pressure - Engine Off
Indicates the fuel pressure is lower than expected with the engine off.
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What it means (plain English)
When the engine is off, the fuel pressure should hold steady but here it's too low, meaning there's likely a leak or the pump isn't holding pressure correctly.
What the computer is actually seeing
The engine control module (ECM) expects to see a fuel pressure of at least 50 PSI (pounds per square inch) when the engine is turned off. When it registers below that, it triggers SPN 5317.
What a healthy reading looks like
Fuel pressure should be 50 PSI or above when the engine is off.
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 for visible fuel leaks around connections and fuel lines. Confirm all connections are tight. Decision: If leaks are found, repair and retest. If no leaks, proceed to step 2.
- 22. Inspect fuel pressure using a gauge. Connect the gauge to the fuel rail and note the pressure with the engine off. Decision: If pressure is less than 50 PSI, proceed to step 3. If pressure is good, clear the code and monitor for reoccurrence.
- 33. Check the fuel pump operation. Ensure proper voltage and ground are present at the fuel pump connector (usually 12V). Decision: If no voltage, trace back to the relay or wiring issues. If voltage is correct, replace the fuel pump.
Common causes
- Leaking fuel lines or connections
- Defective fuel pressure regulator
- Faulty fuel pump
- Clogged fuel filter
- Damaged fuel injectors
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but performance may be affected and fuel efficiency could drop.
Will this code come back after repairs?
If the underlying issue is fixed, it should not return.
Why does this code sometimes pair with low pressure codes?
SPN 5317 indicates low fuel pressure when the engine is off, which suggests issues in the fuel system could also trigger active pressure-related faults.
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