P0EA7Auxiliary Cooling System Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P0EA7 reports that an auxiliary cooling loop, a coolant circuit kept apart from the main engine circuit, does not achieve the cooling effect the controller expects. Volvo documents the code for its T8 plug-in hybrids of model years 2016 to 2019 (XC90, S90, XC60, S60 and others): the engine control module stores P0EA773, fault type actuator stuck closed, and turns on the check-engine light. Technical Journal 34123 traces it to the thermostat in the cooling coil of the electric rear axle drive and calls for a revised part with a small orifice, fitted in the correct orientation, followed by a coolant refill. Ford lists P0EA7:19 among codes that faulty dynamics-module software can leave in the PCM of the 2025-2026 Mustang GTD; reprogramming cures it there. Sensor faults of the same loop are P0E81 to P0E84.
- What you may notice
- Check-engine light on
- Often no noticeable change in driving behaviour
- Possible power limits on electric drive parts that run too warm
- Likely causes
- LikelyThermostat in the auxiliary loop sticking closed (Volvo T8, earlier part design)
- PossibleLow coolant level or trapped air in the auxiliary loop
- RareWeak or failed auxiliary coolant pump
- RareModule software reporting the fault wrongly (Ford Mustang GTD)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.