Powertrain, generic · Hybrid propulsion

P0C12 Drive Motor A Inverter Phase V Over Temperature

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P0C12 sets when the inverter for motor A measures an excessive temperature at phase V while its sensor itself is plausible. In GM's 2011 Volt table that is PIM sensor C above 98 °C; the two-mode trucks of 2012 use 88 °C with an 85 °C reset, the 2016 Volt 126 °C for 1.2 s out of 2 s and the 2016 ELR 102.5 °C, all Type A, one trip. The sensor circuit codes of that thermistor, such as P0BD1 and P0BD2, have their own numbers and must be ruled out first. P0C11 and P0C13 are phases U and W, P0C15 is phase V on motor B. GM bulletin PIC6303A lists these overheat codes as a sign of insufficient cooling. Power is reduced while the inverter is hot.

Likely causes

Low coolant level or trapped air in the inverter cooling loop

Inoperative electric coolant pump of the power electronics

Blocked low-temperature radiator or failed cooling fan

Degraded thermal contact or failing power stage inside the inverter

Symptoms

Malfunction indicator lamp after one drive
Propulsion power reduced, especially under load or in hot weather
Hybrid system overheat or service 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 a inverter phase v

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.