FMI 7 - Water in Fuel Indicator
Indicates that water has been detected in the fuel system.
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)
The system is telling you there's water in the fuel—something you need to deal with to keep the engine running right.
What the computer is actually seeing
The ECM detects a high water concentration in the fuel, usually indicated by a specific sensor reading above a set threshold.
What a healthy reading looks like
Normal fuel system water content should be less than 0.05% (500 ppm); above that can trigger the code.
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 and drain water if there is any present. Decision: If no water is present, proceed to step 2. If water is present, replace the fuel filter.
- 22. Inspect the water-in-fuel sensor and its wiring for damage or corrosion. Decision: If wiring is damaged, repair or replace it. If it looks good, proceed to step 3.
- 33. Test the water sensor using a multimeter; it should show a resistance value within specs (typically around 1000-2000 ohms). Decision: If values are out of spec, replace the sensor. If values are correct, check fuel quality.
Common causes
- Contaminated fuel
- Faulty water sensor
- Fuel filter clogged with water
- Poor fuel storage conditions
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to avoid driving until you address the issue, as water in the fuel can cause engine performance issues.
Will this code come back after clearing?
If the source of the water is not fixed, or if the sensor is faulty, it will likely return.
Why does it seem related to other SPNs?
Other SPNs can indicate different aspects of fuel contamination, often leading to similar symptoms.
Working a real vehicle right now?
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