Powertrain, generic · Hybrid propulsion

P0C14 Drive Motor B Inverter Phase U Over Temperature

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0C14 is the motor B counterpart of P0C11: phase U of the second inverter has become too hot while its temperature sensor reads plausibly. GM documents it on the Volt and the two-mode trucks. The 2011 Volt compares PIM sensor B with 98 °C, the 2012 trucks use 88 °C with a reset at 85 °C, the 2016 Volt 131 °C for 1.2 s in 2 s and the 2019 table 131 °C for 1.5 s, all Type A, one trip. Sensor circuit codes such as P0AF2 or P0AF3 point to the thermistor instead and are checked first. P0C15 and P0C16 cover phases V and W. GM bulletin PIC6303A sends technicians to the cooling system when inverter overheat codes appear. Power from motor B is limited meanwhile.

Likely causes

Low coolant level or air in the power electronics cooling loop
Failed electric coolant pump of the inverter loop
Clogged low-temperature radiator or failed cooling fan
Long periods of high load on motor B, e.g. towing or steep climbs

Symptoms

  • Malfunction indicator lamp after one drive
  • Reduced propulsion power, especially under load
  • Hybrid system overheat message

Repair estimate

DifficultyHardWorkshop job
Parts and labour€50–3,500
Time0.5–5 h

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

Parts involved

drive motor b inverter phase u

Related codes

P0C15P0C16P0C11P0AF2P0AF3P0A3DP0C31

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.