Powertrain, generic (extended)

P2ACA Charge Air Cooler Coolant Temperature Sensor B Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2ACA is the opposite end: the voltage from charge air cooler coolant temperature sensor B sits above anything a real temperature would produce. For a thermistor input this looks like extreme cold and is typical of an unplugged connector, a broken signal wire, a lost sensor ground or a short to a voltage source. For sensor A, Ford's 2023 diesel summary sets P00E1 above 4.928 V, and GM's 2025 diesel table above 166,297 ohms, again as Type B. Nothing comparable is published for B. A frozen-looking reading may keep the low-temperature pump idle or make the module distrust the cooler, which on some engines means less boost. Check plug fit and corrosion first; with the two terminals bridged, the live value should jump to the hot end.

Likely causes

Disconnected plug or broken signal wire of sensor B
Open ground or return line of the sensor
Sensor B element open internally
Signal wire shorted to a voltage source

Symptoms

  • Check engine light on
  • Live data shows an extremely low coolant temperature for sensor B
  • Reduced boost on some engines

Repair estimate

DifficultyEasyDIY possible
Parts and labour€60–300
Time0.5–2 h

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

Parts involved

charge air cooler coolant temp sensor bwiring harnessecm

Related codes

P2AC7P2AC9P2AC8P2ACBP00E1

References: fordservicecontent.com, gsi.ext.gm.com, law.cornell.edu.