P0C12: motor A phase V thermal monitoring uses PIM Temp 2

P0C12 is the motor A inverter phase V overtemperature monitor. The GM table associates this row with PIM Temp 2, so sensor numbering must be read from the actual source rather than guessed from alphabetical phase order.

Separate thermal behavior from electrical faults

The input must be in range, and the P0BDC sensor-performance fault must be inactive. Those prerequisites distinguish this thermal diagnosis from an implausible or electrically out-of-range temperature report. Preserve related sensor faults before interpreting the displayed temperature as physical heat.

The source gives an initial fault boundary above 88°C and a lower 85°C reset boundary. Its filter uses 500 qualifying counts within 650 at a 10.4 ms rate. A meaningful record therefore includes the temperature trend and duration context, not only one hot-looking sample.

Verify the actual cause and recovery

The code identifies a qualified in-range overtemperature condition but does not name a failed pump, blocked passage or mandatory replacement component. Those conclusions require the applicable vehicle's cooling and inverter diagnostic information.

After repair, a technician should establish credible temperature behavior and eligible monitor operation, including recovery through the documented lower boundary. Clearing memory after the system cools does not establish the cause has been corrected. High-voltage inverter work requires trained personnel, and the calibration thresholds should not be used as targets for deliberately forcing an overheat event.

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 291.