P073A: fifth gear remains engaged through failed release attempts

P073A identifies repeated failure to disengage fifth gear in the documented transmission. It concerns release toward neutral and should be distinguished from a fault in trying to engage fifth gear.

The relevant position channel

The row names shift-fork position sensor 2. An electrical or consistency fault on that channel during the neutral-directed actuation can make a release attempt fail. Alternatively, the disengagement state can time out because its next transition conditions were not met.

The test requires a fifth-gear disengagement request, active disengagement, system pressure above 4.5 bar, and an application outside error and bypass states. Four failed attempts are required for confirmation. The timeout varies by actuation state through the attachment reference, so the page does not support a single universal seconds value.

Diagnostic priorities

Retain the attempt counter and the state in which progress stopped. That distinguishes repeated lack of confirmed position from a known position with an unmet transition condition. A later successful drive in fifth gear does not verify the ability to release it.

Confirmation should establish successful disengagement and valid position-sensor-2 evidence during the appropriate service test. The source does not identify a worn synchronizer, failed solenoid, or other physical part from the base code alone, and the published counter is not a recommendation to force repeated shifts.

Documentation and applicability

These details describe the monitor in GM’s 2025 25OBDG07A Part2 file. Its application-matrix filename does not match the download index, so model and engine applicability remain unresolved. Use the vehicle’s correct service information before applying these calibration details.

GM diagnostic table, PDF page 1041.