P0C16: motor B phase W overheating is separate from sensor circuit failure

P0C16 is the motor B inverter phase W overtemperature monitor in the GM source. The row evaluates PIM Temp 1 as a thermal input. It should not be interpreted through the separate electrical low/high criteria for the temperature-sensing circuit.

Confirm credible sensing before interpreting heat

The temperature must be in range, and P0BD7 must be inactive. If a performance fault blocks the thermal test, no new P0C16 does not establish that the inverter's cooling behavior is satisfactory. Preserve both thermal and sensing fault records.

GM prints an initial fault boundary above 88°C and a lower 85°C reset boundary. The test requires 500 qualifying counts among 650 at a 10.4 ms rate. These details make the temperature history and repeated evaluation relevant, rather than just one displayed value.

Verify recovery without guessing the repair

The source identifies a qualified in-range overtemperature condition capable of affecting the inverter, but it does not identify the failed cooling component or require replacing the entire assembly. That investigation needs the actual vehicle's hybrid diagnostic procedure.

A useful post-repair record demonstrates credible sensing and normal temperature behavior during eligible operation. Clearing memory after a cooling period is not equivalent to correcting the cause. Physical inverter work must be handled by trained high-voltage personnel; the numerical thresholds must not be treated as targets for a forced-overheat test.

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 303.