P0716: input-speed performance tracks repeated implausible drops

P0716 monitors intermittent, unrealistic drops in transmission input speed in the cited TCM. It is designed around repeated drop events rather than one permanently missing signal.

A drop must begin from usable speed

The strategy requires a previously valid input-speed level and stability conditions before a drop can count. The displayed drop threshold is 650 rpm, evaluated every twenty-five milliseconds. The event must also persist long enough to advance the failure-event counter; the listed failure-time boundary is 1.5 seconds and the count must exceed three.

This explains why a zero input-speed PID by itself is insufficient. The diagnostic needs a qualifying transition and event history. If speed falls and remains low without further transitions, the source says the no-activity/low-speed diagnostic can win the race instead.

Other signals support the judgment

The monitor excludes failures of the related input-speed electrical/no-signal tests and requires appropriate output speed, accelerator position and torque conditions. A drop during an unqualified state does not reproduce the intended plausibility comparison.

Capture the speed trace before, during and after the event, including recovery and associated codes. A single post-event snapshot loses the distinction between repeated dropouts and a sustained loss. Verification should establish stable qualifying behavior and completion of the relevant monitor using the applicable transmission procedure. The code alone does not identify a mechanical slipping element or prove that replacing the speed sensor will correct the fault.

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 1098.