P089C: The second X-position signal needs its own low-duty evidence

P089C identifies low electrical range on gear-lever X position sensor 2. The cited GM monitor reads that sensor's X duty cycle and applies a lower signal boundary. The second-sensor identity is significant even when another selector input appears to report a plausible position.

A duty-cycle finding, not a physical location

The failure criterion is below five percent. The controller must have been awake for at least 0.05 second, after which ten failed samples within twelve are counted at a 25-millisecond task rate. Two-trip reporting is listed separately.

Those details do not provide a direct lever-position or gear-range interpretation. The document supplies no map between duty percentage and selector travel, and an average voltage is not automatically an equivalent representation of this signal.

Compare the correct source of information

Preserve the raw X-channel sequence from sensor 2, along with wakeup timing and fault status. Data from sensor 1 may provide context in a wider investigation, but it cannot demonstrate that sensor 2's own signal passed this monitor.

An early initialization transient differs from repeated low-duty observations after enablement. A normal decoded gear display also does not erase the recorded raw-channel finding. The table does not locate the failure inside the sensor, wiring or controller, or authorize a selector replacement. Use the applicable circuit procedure to resolve the signal path before drawing mechanical transmission conclusions.

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 613.