P0963: solenoid A high-circuit detection uses a short evaluation window

P0963 diagnoses a short-to-voltage signature in pressure-control solenoid A's control circuit. The cited TCM uses controller-specific voltage thresholds corresponding to less than 0.5 ohm between the signal and controller voltage source.

A faster decision than the companion low/open checks

The displayed high-circuit timing requires more than 0.06 second of failure in a sample period exceeding 0.13 second. The neighboring low/open examples use longer windows. That distinction helps explain why a brief high-circuit event can be recorded even when a slower observation later looks normal.

These are electrical timing criteria, not a hydraulic pressure-rise specification. The code does not state that transmission pressure is excessively high.

Solenoid A is an architecture-dependent assignment

The same row lists clutch assignments for several geared transmissions and secondary-pulley control for a CVT. Confirm the installed transmission before identifying the affected actuator. Battery voltage between 9 and 32 volts and an active mapped high-side supply are prerequisites; a no-driver mapping disables evaluation.

Preserve circuit voltage, supply state and current/history status. Verification should exercise the enabled high-circuit monitor and demonstrate the voltage-short signature is absent. A successful gear change alone does not validate the electrical circuit. The table provides no connector pinout or universal replacement instruction, and its impedance specification is not a safe live-circuit resistance-test method.

Source and applicability

Documented monitors in gm-2025-03a, model year 2025. These are module/calibration examples; vehicle, engine and transmission applicability must be confirmed independently. GM 2025-03a, page 1144.