Powertrain, generic (extended)

P238E Water in Fuel Sensor B Circuit Intermittent

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P238E is meant for a water-in-fuel sensor B circuit whose signal flickers or drops out for short periods instead of staying at one fault level. No manufacturer documents P238E publicly. The one published case for the same sensor explains well why such faults come and go: on 2022 Ram heavy-duty trucks Stellantis found water from road spray or pressure washing inside the plug of the frame-mounted filter, logged there as P238D. Moisture that evaporates, terminals that lose contact on rough roads and fuel sloshing over the probe can all produce brief changes. Since the sensor is a plain pair of electrodes, connector, pins and harness clips along the frame rail come first. P238C and P238D are the steady low and high faults.

Likely causes

Moisture entering and drying out in the connector
Loose terminals losing contact on rough roads
Broken harness clips letting the wire rub on the frame

Symptoms

  • Water-in-fuel lamp flickering or coming and going
  • Fault not present when tested at the workshop

Repair estimate

DifficultyEasyDIY possible
Parts and labour€0–250
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

water in fuel sensor bwater in fuel wiring b

Related codes

P238AP238CP238DP2268

References: static.nhtsa.gov, en.wikipedia.org.