P2867: Rod 5 pulse frequency outside its valid window

P2867 is labelled intermittent in the generic dictionary, but the documented GM strategy specifically checks the period of rod 5's digital position signal. Its decision is based on pulse frequency. An electrically active signal can therefore fail this check even when it is neither permanently high nor permanently low.

Timing is the key measurement

The table lists frequencies below 1,500 Hz or above 2,500 Hz as failure conditions, with at least 150 milliseconds of confirmation. This is a timing window for the documented sensor interface. It is not a permissible range of shift speed or fork travel.

Nearby P2865 and P2866 rows check missing pulses and duty-cycle extremes. Comparing the stored code combination helps distinguish an out-of-frequency signal from one that disappeared or became stuck at an input level. That comparison is an interpretation of the published monitor separation, not proof of a particular wiring defect.

Validate the test conditions

Cranking and the key-stop state are excluded. The source also lists battery and reference-supply diagnostics that can disable this monitor. Its VREF2 enable comparisons are internally inconsistent in the available table; no corrected voltage limit is assumed here.

When evaluating a return to normal, retain frequency and signal-validity information during an eligible monitor period. A plausible displayed fork position alone does not establish correct pulse timing. Electrical access and oscilloscope setup must follow the vehicle's service information because this summary supplies no connector pinout or safe probing procedure.

Source and applicability

2025 GM 07A-2 documented monitor only; module and calibration applicability must be matched to the vehicle. The application-matrix filename join remains unresolved; no model or engine fitment is inferred. GM PDF, page 915. GM PDF, page 916.