P2C38 code meaning
Cylinder Head Temperature Sensor B Circuit
Powertrain system Generic code P2Cxx codes Check engine light
What P2C38 means
A cylinder head temperature sensor is an NTC thermistor seated in the head metal that tells the module how hot the engine really is, even without coolant. P2C38 is the general circuit fault of a second such sensor, B: the signal is open, shorted or otherwise unusable, without separating low from high (P2C3A/P2C3B do that, P2C39 judges plausibility). Ford uses it on the 2025 Explorer and Aviator with 2.3 L or 3.0 L EcoBoost: TSB 24-2393 (built until 15 Oct 2024) describes an over-temperature warning with P1299 plus P2C38 or P2C39 although fan and coolant are fine, and cures it by reprogramming the PCM. For sensor A Ford's 2024 summary flags below 0.244 V or above 4.96 V after 5 s. CARB treats head temperature sensors used for emission control like coolant sensors.
P2C38 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2C38
- MIL and engine over-temperature warning
- Fail-safe cooling mode with reduced power possible
- Temperature warning even though coolant level and fan are fine
Common causes of P2C38
- Most likelyPCM software causing false faults (Ford 2025 Explorer/Aviator, TSB 24-2393)
- PossibleLoose or corroded connector at the head sensor
- PossibleFailed head temperature sensor B
- Less likelyHeat-damaged or chafed wiring near the cylinder head
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cylinder head temperature sensor bWiring harnessECM
What each part of P2C38 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| C | Area: hybrid propulsion. |
| 38 | The exact fault in that area. |
What to do next
- Note P2C38 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 P2C38
What does P2C38 mean?
P2C38 means "Cylinder Head Temperature Sensor B Circuit". A cylinder head temperature sensor is an NTC thermistor seated in the head metal that tells the module how hot the engine really is, even without coolant. It is a generic code, so it means the same on every make.
Is it safe to drive with P2C38?
Drive gently and only to a workshop. With P2C38 the car can go into limp mode (reduced power) to protect itself.
Will P2C38 fail an emissions test?
Yes, it can. P2C38 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2C38 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P2C38 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.