P089D: High duty on X sensor 2 must be assessed after controller wakeup

P089D is the high-circuit result for gear-lever X position sensor 2. GM's documented assessment checks this particular channel's measured duty cycle. It does not establish that the lever has reached a high physical position or that the transmission is in a certain range.

Watch the upper boundary over eligible samples

The signal is classified high above ninety-five percent. The controller must have been awake for at least 0.05 second before the monitor operates. It requires ten failing samples within twelve on a 25-millisecond loop, with two-trip reporting.

A brief transition before that enable point does not reproduce the same test. Neither does a single normal sample prove that all qualifying observations remained inside range. The relevant evidence is the signal sequence and the controller's state during it.

Keep sensor 2 separate in the investigation

Retain the X duty measurement for sensor 2 specifically. Another selector sensor may still produce a plausible decoded gear indication while this channel is electrically outside its expected range. The table does not establish how those signals are combined into the final displayed position.

No connector voltage conversion or duty-to-travel map is provided. The monitor therefore supports a focused electrical-range investigation without naming a failed component or prescribing a mechanical transmission repair. The correct selector-system service information is needed to isolate the sensor, connection or receiving circuit.

Source and applicability

2025 GM 03B documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file. GM PDF, physical page 614.