Water In Fuel Indicator
Indicates the presence of water in the fuel system.
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What it means (plain English)
The truck has detected water mixed with the fuel, which can cause engine performance issues and potential damage.
What the computer is actually seeing
The engine control module (ECM) monitors the fuel system for water presence using a sensor that typically sends a signal based on voltage levels. If the voltage indicates excessive water, it triggers this code.
What a healthy reading looks like
The sensor generally outputs between 0V (no water) and 5V (significant water presence).
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 filter for signs of water contamination; drain if necessary.
- 22. Inspect the wiring and connectors of the water-in-fuel sensor for damage or corrosion.
- 33. Use a multimeter to test voltage at the water-in-fuel sensor; should be low (under 1V) if no water present.
- 44. If voltage is high or fluctuating, replace the water-in-fuel sensor and clear the code.
- 55. Recheck system operation; if code returns, inspect the fuel for contamination or other underlying issues.
Common causes
- Faulty water-in-fuel sensor
- Contaminated fuel
- Bad fuel filter
- Leaky fuel lines
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means you can drive but should fix soon to avoid engine issues.
Will this code come back after reset?
If the root cause isn't fixed, yes, it will likely come back.
Why does this code appear with low fuel pressure?
Low fuel pressure can allow water to accumulate, leading to this code showing due to fuel quality issues.
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