P2ACACharge Air Cooler Coolant Temperature Sensor B Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- Check engine light on
- Live data shows an extremely low coolant temperature for sensor B
- Reduced boost on some engines
- Likely causes
- LikelyDisconnected plug or broken signal wire of sensor B
- PossibleOpen ground or return line of the sensor
- PossibleSensor B element open internally
- RareSignal wire shorted to a voltage source
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €60 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.