P238A: Water in Fuel Sensor B Circuit
Standardized SAE J2012 code · P23xx — Ignition system and misfire
What does P238A mean?
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.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Common causes
- High Open in sensor or wiring
Likelihood is a general estimate across vehicles; your make and model may differ.
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P238A in the community
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