P0C11: motor A phase U overheating requires a credible temperature signal

P0C11 is the motor A inverter phase U overtemperature diagnosis in the cited GM table. Unlike a temperature-sensor circuit code, this monitor requires a temperature input already considered in range. The source describes a thermal condition capable of damaging the inverter.

Understand the thermal boundaries

The documented input is PIM Temp 0. GM specifies an initial fault boundary above 88°C and a lower 85°C reset boundary, so detection and recovery do not use one identical temperature point. The table also applies 500 qualifying counts among 650 at a 10.4 ms rate.

That combination means a brief sample near the boundary and a qualified thermal event are different observations. Preserve the temperature history rather than diagnose solely from one value after the inverter has cooled.

Measurement validity comes first

The PIM temperature must be in range, and its performance fault P0AEE must be inactive. If those requirements are not met, the thermal monitor may be unavailable; the absence of P0C11 does not prove a satisfactory cooling condition.

The source does not identify a failed cooling component or prescribe inverter replacement. A trained hybrid technician must use the actual vehicle procedure to establish the thermal cause and verify recovery. The numerical boundaries are historical calibration values, not permission to deliberately heat the inverter or bypass its protective behavior.

Source and applicability

GM 2010 10OBDG10 Hybrid Diagnostics, cited BPCM or hybrid-controller monitor only. Historical calibration values are not universal specifications; no per-code model, engine or hardware fitment has been established. GM PDF, physical page 290.