P0EF1 is the general circuit code for the temperature sensor of drive motor C, the third traction motor on vehicles with three or more electric machines. It must not be confused with P2DB1, which means sensor C inside drive motor A. Volvo Trucks lists P0EF1 with failure type 09, component failure, for its electric trucks in remote diagnostic bulletin RD21-022; it names connector, wiring harness, the motor temperature sensor itself and an unsupported configuration as possible causes and sends the technician to Tech Tool for the detailed steps. The general code is used when the fault is not classified as low or high, which have their own codes P0EF3 and P0EF4. Without a usable winding temperature the controller has to protect motor C and limits its output.
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
- Reduced drive power
- Warning lamp for the electric drive
- Motor temperature shown as invalid in the scan tool
Most likely causes
- Loose, corroded or damaged connector of the motor C temperature sensor
- Chafed or broken sensor wiring
- Temperature sensor in the winding failed
- Controller configuration not matching the installed motor (Volvo RD21-022)
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It can trigger limp mode.
- It affects emissions.
What each character of P0EF1 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- E: Subsystem depends on the code range
- F1: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0EF1?
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 P0EF1?
The most common causes are: loose, corroded or damaged connector of the motor C temperature sensor; chafed or broken sensor wiring; temperature sensor in the winding failed.
Related codes
- P0EF2Drive Motor C Temperature Sensor Range/Performance
- P0EF3Drive Motor C Temperature Sensor Circuit Low
- P0EF4Drive Motor C Temperature Sensor Circuit High
- P0EF5Drive Motor C Temperature Sensor Circuit Intermittent/Erratic
- P0A30Drive Motor B Temperature Sensor Circuit
- P2DB1Drive Motor A Temperature Sensor C Circuit
Sources
- static.nhtsa.gov: MC 10194951 0001
- fordservicecontent.com: OBDSM1901 HEV
- law.cornell.edu: 13 CCR 1968.2
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.