SPN 97 FMI 16 — Water in Fuel — Detected
The water-in-fuel sensor in the fuel/water separator has tripped. Water in diesel can damage injectors and the high-pressure pump, so address it before it becomes an expensive fuel-system failure.
Look up listed providers near you and give them this SPN/FMI when you call.
How serious is it?
Caution. Limp to the next safe stop.
Most likely causes
- Water collected in the fuel/water separator bowl (needs draining)
- Contaminated fuel from a bad fill
- Condensation in a low/empty tank
- Faulty water-in-fuel sensor (verify after draining)
First moves (roadside)
- Drain the fuel/water separator bowl — that's the first and usually the fixing step.
- If it refills with water quickly, suspect a contaminated tank/bad fuel.
- Replace the fuel filter if water has carried through.
- If the bowl is dry but the code stays, suspect the sensor.
Common misdiagnoses
- Ignoring the warning and running water through the injectors and pump.
- Replacing the sensor without first draining the separator.
- Missing a contaminated tank that keeps refilling the separator with water.
FAQ
The water-in-fuel sensor in the fuel/water separator has tripped. Water in diesel can damage injectors and the high-pressure pump, so address it before it becomes an expensive fuel-system failure.
Caution — Limp to the next safe stop.
The most common cause is: Water collected in the fuel/water separator bowl (needs draining). Other possibilities include Contaminated fuel from a bad fill; Condensation in a low/empty tank; Faulty water-in-fuel sensor (verify after draining).
Limp to the next safe stop. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Find a mechanic or related guides
General diagnostic guidance for heavy-duty diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack). Not a substitute for a scan-tool diagnosis on your specific truck.