P0C2B: auxiliary transmission-pump feedback is a communication check here

P0C2B is the auxiliary transmission-fluid-pump feedback code in the cited GM hybrid table. The source defines this particular feedback problem as incomplete or missing fault-message communication between the transmission auxiliary oil-pump controller and the hybrid control processor.

Distinguish communication from pump speed

A complete fault-status message is expected every 1.5 seconds. The monitor requires RunCrankActive for more than 0.2 seconds and lists a 9.75-second failure time. These conditions concern communication completeness, not a measured difference between commanded and actual pump speed.

The separate P2797 row on the same page evaluates pump-speed performance. Its RPM threshold and retry behavior must not be copied into a P0C2B diagnosis simply because both rows concern the same auxiliary pump.

Verification has its own timing

The pass row requires complete communication with the same message interval and lists 1.75 seconds for recovery evaluation. A single received fragment or a briefly cleared code does not establish that the complete status exchange is consistently restored.

Preserve communication status and companion pump or controller faults so a technician can follow the correct vehicle-specific path. The source does not identify a failed pump motor, require replacing the pump assembly or publish a universal connector test. Physical diagnosis must follow the actual hybrid service precautions, and confirmation should demonstrate sustained complete message communication under the documented operating state.

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 164.