Powertrain, generic

P0EF3 Drive Motor C Temperature Sensor Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0EF3 is stored when the signal voltage of the drive motor C temperature sensor drops below its valid range. With the usual NTC thermistor on a pull-up resistor, a low voltage stands for an extremely hot winding, so electrically the suspects are a short to ground, a pinched harness or a sensor with an internal short. No manufacturer documents P0EF3 publicly. GM's motor B table for the 2016 Cadillac ELR shows the analogous limit: P0A32 trips once the reading corresponds to more than 184 °C, close to 0 V, after a 90 s warm-up, Type A. Ford's 2019 hybrids fail the motor coil sensor below 0.1 V held for 32 ms. Because the controller cannot tell such a short from real overheating, it derates motor C. P0EF4 covers the high-voltage side.

Likely causes

Signal wire shorted to ground or motor housing
Thermistor shorted internally
Water or coolant in the connector bridging the pins

Symptoms

  • Drive power of motor C reduced immediately
  • Implausibly high motor temperature in the live data
  • Warning lamp on

Repair estimate

DifficultyHardWorkshop job
Parts and labour€50–2,500
Time0.5–6 h

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

Parts involved

drive motor c temp sensorwiring harnesshybrid control module

Related codes

P0EF4P0EF1P0EF2P0EF5P0A32P0A2C

References: gsi.ext.gm.com, fordservicecontent.com, law.cornell.edu.