P2797: CVT auxiliary pump supplies inadequate pressure during an auto-stop event

P2797 is an auxiliary transmission-pump pressure-performance diagnosis in the reviewed GM CVT-specific row. It uses primary- and secondary-pulley pressure sensors to determine whether the requested auxiliary pumping support is producing sufficient pressure.

Both measured pressures must be low

The failure condition requires primary pressure below 200 kPa and secondary pressure below 200 kPa. At the same time, commanded pressure for each pulley must exceed 400 kPa and commanded auxiliary pump speed must be greater than zero.

This distinction matters: one low sensor alone does not reproduce the documented combined condition, and a low pressure while pressure is not being requested has a different interpretation. Commanded and measured values need to be considered together.

The operating window is specific

Although the strategy introduction mentions auto-start operation, the explicit enable state is engine off with auto-stop active and the propulsion system active. Those conditions qualify a delay timer that must exceed 1.2 seconds before evaluation.

Failure time must then exceed 0.525 second to increment the event count; more than three events are required, at a 6.25-millisecond update rate. A brief pressure transition at the beginning of auto-stop is not automatically the completed fault.

Verification should confirm the actual CVT system and adequate pressure response through the eligible event using the applicable procedure. The code does not isolate the motor from hydraulic or measurement causes. The source lists Type B, two-trip behavior without a mandatory auxiliary-pump replacement.

Source and applicability

Keep the stated transmission function and source calibration separate from other applications. GM diagnostic table, PDF page 1195.