Powertrain, generic (extended)

P2C39 Cylinder Head Temperature Sensor B Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2C39 flags a second cylinder head temperature sensor, B, whose voltage is electrically valid but whose reading does not fit the engine's state, for instance a value that jumps, lags or disagrees with other temperature inputs. Ford is the documented user, all on EcoBoost engines: TSB 24-2441 and its successor 26-2217 (F-150 2.7 L, 2024–2025) pair it with P1299 or P1285 and an over-temperature warning while fan and coolant are fine; a 2024 truck with P2C39 gets new PCM software, the CHT sensor is renewed only if P1285/P1299 persist. TSB 24-2393 (2025 Explorer/Aviator 2.3/3.0 L built to 15 Oct 2024) and 25-2206 (Bronco/Ranger 2.7 L built to 17 Mar 2025) also cure it by reprogramming. Out-of-range voltages are P2C3A/P2C3B.

Likely causes

PCM calibration misjudging sensor B (Ford EcoBoost bulletins, cured by reprogramming)
Sensor B drifted or responding slowly
Sensor not seated properly in the head or corroded terminals
Genuine local overheating from low coolant or trapped air

Symptoms

  • Engine over-temperature warning although the gauge and coolant level look normal
  • Check engine light, often together with P1299 or P1285
  • Reduced power while the fail-safe cooling strategy is active

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–400
Time0.3–2 h

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

Parts involved

cylinder head temperature sensor bwiring harnessecm

Related codes

P2C38P2C3AP2C3BP2C3CP2C3DP017B

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.