Fuel Filter Water (Diesel)
Caution — Service soon
What It Means
Water has accumulated in the diesel fuel filter/water separator and needs to be drained. Water in diesel fuel can cause injector damage, fuel pump failure, and microbial growth in the fuel tank.
Common Causes
- Condensation in fuel tank (common in humid climates)
- Contaminated fuel from a gas station
- Fuel filter water separator full (needs draining)
- Water-in-fuel sensor fault
Can I Still Drive?
Yes short-term — but drain the water separator as soon as possible. Water in diesel fuel causes catastrophic injector and pump damage if not addressed. Most diesel vehicles have a drain valve on the fuel filter housing that can be operated without tools. If the light returns quickly after draining, the fuel tank may need flushing.
Estimated Repair Cost
$0 – $500
This is an estimate only. Actual costs vary by vehicle make, model, year, location, and shop labor rates. Always get multiple quotes for major repairs.
Related OBD-II Trouble Codes
These OBD codes are commonly associated with this warning light. Scan your vehicle with an OBD-II scanner to get the exact code before diagnosing.