P0CEE: Hybrid/EV Electronics Coolant Temperature Sensor A Circuit
What to do
As P0CEE. If the car has become slower to charge or less willing under load with nothing else changed, this is a good candidate — the reading sets both limits, so one faulty sensor costs performance and charging speed at once.
What this code means
The sensor measuring the electronics coolant temperature has a circuit fault.
This is the third of the vehicle's coolant temperature measurements and the one that governs the most. The battery loop is at P0C42, the motor's at P0CBC; this one watches the circuit cooling the inverter, the on-board charger and the DC/DC converter — the three things whose temperature limits decide how fast the car can accelerate and how fast it can charge.
So a wrong reading here is expensive in capability rather than in parts. Reading falsely high makes a perfectly healthy car derate and charge slowly; reading falsely low is the more dangerous direction, because the protection that should intervene will not.
As with the others, the reservoir is separate from the engine's and is routinely missed at service.
Likely causes
Start here
- Faulty inverter coolant temperature sensor · moderate
- Corroded or loose connector · easy
Less common
- Low inverter coolant level · easy
- Coolant leak into the sensor connector · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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