P2266
Water in Fuel Sensor A Circuit Low
The water-in-fuel sensor at the diesel fuel filter reads below lower plausibility — short to ground. The sensor warns the driver to drain the filter when condensate accumulates.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: easy
Common causes
Ordered by how often each turns out to be the cause.
- Short to groundCommon
- Connector pins corroded - high contact resistanceLess likely
- Harness chafing through insulationLess likely
Parts involved
- Water In Fuel Sensor
- Fuel Filter
P2266 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.