P0C0B: motor A inverter supply failure is reported through a bias-status flag

P0C0B is the motor A inverter power-supply circuit/open diagnosis in this GM source. The monitor detects an IGBT bias fault through a status indication from a phase power supply. It is not a direct instruction to replace the traction battery because the title contains power supply.

Identify the actual failure evidence

The row's criterion is a FAILED status bit for a phase A, B or C power supply. This differs from the neighboring inverter-performance row, which uses an overdriven or desaturation indication. Preserve the specific status and related inverter faults instead of treating the two codes as interchangeable.

GM lists a one-count evaluation at a 2.08 ms rate and one-trip reporting. A single stored event still does not identify which physical connection or internal component caused the status flag.

Do not repair ambiguous enable text by assumption

The voltage-enable field is printed with an OR relationship between its upper and lower comparisons, rather than an unambiguous operating window. This article does not turn that wording into a universal pass/fail voltage specification. Confirm the applicable controller calibration and service procedure.

The parameter table contains no safe bias-supply probing method or required replacement. Physical inverter diagnosis requires trained hybrid personnel and proper high-voltage isolation. Verification should establish normal relevant status and eligible operation after the cause is addressed, rather than rely on cleared codes alone.

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 285.