P238F is no wiring fault: it states that water-in-fuel sensor B has detected water, meaning the separator at that point has collected enough to bridge the probe. Ram's 2022 heavy-duty pickups (2500 to 5500) are covered by Stellantis case S2214000004, which keeps it apart from the circuit code P238D: with P238F stored, the filter on the frame has to be emptied completely and the fuel tested for water before any electrical diagnosis. For sensor A the equivalent is P2269, which Ram's 2025–26 Cummins trucks report with the MIL. Water in diesel fuel damages high-pressure pumps and injectors and promotes microbial growth, so drain promptly, find the source (tank, fuel station, condensation) and replace the filter if needed.
Low severity. Can I keep driving?You can normally keep driving. If it affects the fuel level, do not trust the gauge and refuel earlier than usual.
Symptoms
- Water-in-fuel lamp or message on
- Rough running or power loss if water reaches the injection system
- MIL on some vehicles
Most likely causes
- Water collected in the chassis filter separator
- Fuel contaminated with water from tank or filling station
- Separator drained incompletely after an earlier warning
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: easy
- It affects emissions.
What each character of P238F means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 3: Ignition and misfires
- 8F: Specific fault in that system
Frequently asked questions
Can I keep driving with code P238F?
You can normally keep driving. If it affects the fuel level, do not trust the gauge and refuel earlier than usual.
What causes code P238F?
The most common causes are: water collected in the chassis filter separator; fuel contaminated with water from tank or filling station; separator drained incompletely after an earlier warning.
Related codes
- P238DWater in Fuel Sensor B Circuit High
- P238AWater in Fuel Sensor B Circuit
- P2269Water in Fuel Condition - Sensor A
Sources
- static.nhtsa.gov: MC 10229750 9999
- static.nhtsa.gov: MC 11031447 0001
- en.wikipedia.org: Water in fuel sensor
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.