P0CBC is the general code for the sensor that measures coolant temperature in the cooling loop of drive motor A. Volvo and Polestar document it as P0CBC62 in the inverter module IEM of the Polestar 2 and the XC40/C40 Recharge (Technical Journals 37523 and 37521 from 2025): failure type 62 marks a signal comparison fault, and the vehicle displays a propulsion service message. In many of these cars the root cause was a defective check valve in a coolant hose, not the module. The phase transistor temperatures then swing widely while driving; at 80–100 °C the IEM sets a temperature code and freewheels, which stops a single-motor car and halves power on dual motors. Before replacing the IEM, plot those temperatures and renew the valve hose. CARB section (e)(15.2.3)(B)(ii) covers inverter cooling inputs.
High severity. Can I keep driving?If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.
Symptoms
- Propulsion system service message
- Loss of drive power, car may stop on single-motor versions
- Half power only on dual-motor versions
Most likely causes
- Faulty one-way valve in the drive unit coolant hose (Volvo/Polestar TJ 37521/37523)
- Low coolant or trapped air in the drive motor loop
- Sensor or wiring fault in the temperature circuit
- Internal fault of the inverter module
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- It can trigger limp mode.
What each character of P0CBC means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- C: Subsystem depends on the code range
- BC: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0CBC?
If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.
What causes code P0CBC?
The most common causes are: faulty one-way valve in the drive unit coolant hose (Volvo/Polestar TJ 37521/37523); low coolant or trapped air in the drive motor loop; sensor or wiring fault in the temperature circuit.
Related codes
- P0CBDDrive Motor A Coolant Temperature Sensor Circuit Range/Performance
- P0CBEDrive Motor A Coolant Temperature Sensor Circuit Low
- P0CBFDrive Motor A Coolant Temperature Sensor Circuit High
- P0CC0Drive Motor A Coolant Temperature Sensor Circuit Intermittent
- P0CC1Drive Motor A Coolant Pump Control Circuit/Open
- P0A3CDrive Motor A Inverter Over Temperature
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.