P0E81Auxiliary Cooling System Coolant Temperature Sensor A Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P0E81 is the general circuit code for temperature sensor A in an auxiliary cooling loop, a coolant circuit separate from the main engine loop, such as a heater loop of a plug-in hybrid or a loop that cools electric drive parts. The module sees a signal it cannot use at all, without classing it as too low, too high or implausible. No manufacturer documents P0E81 publicly. Ford's 2019 hybrid summary describes a comparable sensor, ECT2, placed between the electric PTC heater and the heater matrix, and checks its circuit through the analog input under P2184 and P2185. Volvo uses the term auxiliary cooling system for its T8 hybrids under P0EA7. CARB requires temperature sensors of this kind to be checked for circuit continuity. The more specific siblings are P0E82 to P0E84.
- What you may notice
- Check engine light
- Heater or auxiliary pump runs on default values
- Likely causes
- LikelyLoose, corroded or unplugged sensor connector
- PossibleFailed temperature sensor A
- PossibleDamaged signal or reference wire
- 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: €40 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.