OBD-II code · Powertrain (generic, extended)
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.
Is it safe to drive with P238A?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen in sensor or wiring
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.4–1.4 h
- Emissions test
- Usually unaffected
- Parts involved
- Water In Fuel Sensor B, Fuel Filter Housing B
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.