Diagnostic article Generic OBD-II
P072C: first gear fails repeated disengagement attempts
P072C means first gear was diagnosed stuck during disengagement in the cited transmission monitor.
Read before applying this article
Documented application
2025 GM 25OBDG07A Part2 diagnostic monitor documentation; the application-matrix filename mismatch is unresolved, so no model or engine applicability is inferred.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P072C means first gear was diagnosed stuck during disengagement in the cited transmission monitor. The controller judges attempts to move the synchronizer toward neutral, rather than treating any commanded first-gear operation as a fault.
Position evidence or a state timeout
A disengagement attempt can fail when shift-fork position sensor 1 develops an electrical or consistency fault during actuation toward neutral. Another route is failure to meet a state-transition condition before the calibrated disengagement timeout. The actual state-specific timeout is delegated to the source’s attachment tables.
The first-gear disengagement request and active state must be present, system pressure must exceed 4.5 bar, and the application must not be in error or bypass state. Fault confirmation requires at least four failed disengagement attempts.
What “stuck” does and does not prove
A position-sensor fault can contribute to this result, so the label does not independently prove that the gear mechanism is physically jammed. Identify whether the failed attempts involved position validity or a timed-out state transition.
Verification should demonstrate successful eligible first-gear disengagement and trustworthy position information using the correct transmission procedure. The four-attempt rule describes the controller’s decision, not an instruction to force repeated shifts or disassemble the gearbox without further diagnosis.
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.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Stuck in Gear 1
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT