Powertrain, generic

P0EF2 Drive Motor C Temperature Sensor Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0EF2 flags a plausibility error of the drive motor C temperature sensor: its signal is electrically fine, yet the value does not fit what the controller expects. No manufacturer documents P0EF2 publicly. GM shows a typical check for drive motor B on the 2016 Cadillac ELR: after at least 21,600 s with the propulsion system inactive, the motor thermistor may differ by no more than 20 °C from the average of power electronics coolant and transmission fluid temperature, otherwise P0A31 sets as Type A. Ford compares motor coil, generator coil and transmission fluid temperatures on its 2019 hybrids after 200 minutes key-off, with limits of 10 °C and 30 °C. A drifting thermistor, a sensor that has lost contact with the winding or a high-resistance connection fails such a cold-start comparison.

Likely causes

Thermistor characteristic drifted with age
Sensor no longer in thermal contact with the winding
Corroded pin adding resistance and shifting the reading
Comparison sensor such as coolant or oil temperature reading wrong

Symptoms

  • Warning lamp after a long standstill, often at the first start of the day
  • Usually no noticeable drivability change at first
  • Power limitation of motor C in some cases

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

P0EF1P0EF3P0EF4P0EF6P0A31P0A2B

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