P238C code meaning
Water in Fuel Sensor B Circuit Low
What P238C means
P238C is set when the signal line of water-in-fuel sensor B stays below its valid range. Because the sensor reads conductivity, anything that bridges its terminals or pulls the signal to ground can cause it: a chafed wire, a wet connector or a sensor body full of water. No manufacturer documents P238C publicly. For the matching sensor A code P2266 Ford bulletin 18-2133 on 2017–18 Super Duty 6.7L trucks traced the fault to water in connector C3080 and specified a sensor resistance of 795 to 815 kOhm across pins 1 and 2; on Ram trucks sensor B is the one in the chassis filter. Since a wet plug may imitate both a low circuit and real water, check for P238F as well. The opposite fault is P238D.
P238C at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P238C
- Water-in-fuel lamp on
- Fault appears after washing or rain
Common causes of P238C
- Most likelyWater bridging the terminals in the sensor connector
- PossibleSignal wire chafed through to ground on the frame
- PossibleSensor resistance out of specification
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Water in fuel sensor b
What each part of P238C means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 3 | Area: ignition system or misfire. |
| 8C | The exact fault in that area. |
What to do next
- Note P238C and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P238C
What does P238C mean?
P238C means "Water in Fuel Sensor B Circuit Low". P238C is set when the signal line of water-in-fuel sensor B stays below its valid range. It is a generic code, so it means the same on every make.
Is it safe to drive with P238C?
P238C does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P238C fail an emissions test?
P238C is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P238C to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P238C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.