P073C: Seventh-gear stuck detection follows position sensor 2

P073C is the stuck-in-seventh-gear code. In the cited GM controller, the monitor follows the attempt to move the seventh-gear synchronizer toward neutral and includes shift-fork position sensor 2 in its evidence.

Feedback and actuation are both considered

A sensor-2 electrical or consistency fault during the shift can prevent the disengagement sequence from qualifying as successful. A separate path checks whether the required actuation-state transition remains unmet until its calibrated timeout.

The seventh-gear disengagement request must be active, system pressure must exceed 4.5 bar, and the application must be outside error and bypass states. At least four failed attempts are needed for confirmation.

A stuck label does not identify a jammed component

Preserve the neutral request and the feedback at the instant the sequence stopped. The controller’s final stuck diagnosis may reflect loss of trustworthy position information as well as failure of the actuation sequence. It does not, by itself, distinguish those possibilities.

This is not an engagement or gear-ratio monitor. A successful request to enter another gear is also not direct proof that the seventh-gear disengagement path is healthy. The exact timeout values and sensor mapping require the installed transmission’s service information. Use that procedure to investigate the recorded branch; the summary does not support a forced-shift test or automatic replacement of a fork, sensor or transmission assembly.

Source and applicability

This explanation covers the cited GM monitor, not every vehicle carrying this code. The application-matrix filename does not resolve cleanly to this file, so no model or engine fitment is assigned. GM diagnostic table, PDF page 1041; GM diagnostic table, PDF page 1042.