Powertrain, generic · Hybrid propulsion

P0CBC Drive Motor A Coolant Temperature Sensor Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

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.

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

Symptoms

  • Propulsion system service message
  • Loss of drive power, car may stop on single-motor versions
  • Half power only on dual-motor versions

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–3,500
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

drive motor a coolant temp sensorwiring harnesshybrid control module

Related codes

P0CBDP0CBEP0CBFP0CC0P0CC1P0A3C

References: static.nhtsa.gov, static.nhtsa.gov, law.cornell.edu.