P238A — Water in Fuel Sensor B Circuit
A general circuit fault on the secondary water-in-fuel sensor B - typically used on diesel systems with two filter housings (pre-pump and post-pump). The ECU loses water-detection feedback on this stage; risk of water reaching the high-pressure pump and injectors.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Water in fuel sensor b
- Fuel filter housing b
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Open in sensor or wiring
Diagnostic notes
- The malfunction indicator lamp may illuminate
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.