P06E8: sensor supply C is above the ATPC limit

P06E8 in the cited GM ATPC summary means sensor power supply C is reported too high. The source identifies a nominal 15-volt sensing supply and an upper diagnostic threshold of 18 volts, with the wake-up signal active.

A high sensor supply is not a charging-system verdict

The same document separately monitors the controller's ordinary system voltage. P06E8 therefore should not be treated as proof that the vehicle alternator or low-voltage battery is overcharging. The exact monitored supply must be identified first.

Nor does the code establish excessive transmission fluid pressure. The controller section concerns an auxiliary pump, but this particular row evaluates an electrical supply channel rather than hydraulic performance.

Retain the timing and polarity

The source uses a failed-sample window or an alternative continuous-failure duration. A brief display spike may be useful evidence, but the complete setting criterion requires the documented persistence. Capture the controller's wake-up state and whether the high result remains present.

P06E7 is the lower-limit branch for the same supply. If both appear in the history, keep their timing separate; the summary does not authorize averaging the two readings or assuming two failed components.

The table provides no approved internal probing or regulator-replacement procedure. Use the applicable service information and qualified hybrid-system handling to determine what can be tested or serviced. A successful recheck must exercise the awake controller's monitor and establish valid supply behavior under those conditions.

Application limits

Document-level 2015 GM diagnostic table; per-code vehicle/engine/calibration applicability not established.

Source

15OBDG01 Hybrid Diagnostics, physical PDF pages 699.