Fuel Filter Differential Pressure
Indicates excessive differential pressure across the fuel filter.
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What it means (plain English)
The engine’s computer is seeing that the fuel filter is too clogged or restricted, which makes it hard for the engine to get enough clean fuel.
What the computer is actually seeing
The engine control module (ECM) tracks the pressure on either side of the fuel filter. If the difference exceeds about 5 psi over time, it triggers this code.
What a healthy reading looks like
Normal differential pressure across the fuel filter should be less than 5 psi during operation.
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 condition of the fuel filter; replace if it looks dirty or clogged.
- 22. Inspect fuel lines for kinks or damages that could restrict flow.
- 33. Measure the fuel pressure before and after the filter; it should be within expected limits (typically 4-6 psi). If the pressure drop is greater, replace the filter.
- 44. Verify fuel quality and check for contaminants in the fuel system; drain and replace if necessary.
- 55. Clear the code and run the engine; if it returns, further diagnose the fuel pressure regulator.
Common causes
- Clogged fuel filter
- Contaminated fuel
- Faulty fuel pressure regulator
- Damaged fuel lines
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not advisable; a clogged filter can lead to engine stalling or loss of power.
Will this code come back after clearing it?
Yes, if the underlying issue isn't fixed, the code will likely return.
Why is this code linked to fuel quality?
Poor fuel quality can lead to quicker clogging of the filter, affecting differential pressure.
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