Code 24, Vehicle Speed Sensor (Pm Generator): Notes

The Permanent Magnet (PM) generator mounted in the transmission, produces a pulsing voltage signal whenever the vehicle speed is greater than 3 MPH. The voltage level and the number of pulses increase with vehicle speed. The ECM converts the pulsing voltage to MPH, which is used by the ECM in calculations to determine vehicle adjustments.

1. Code 24 will set if vehicle speed equals zero MPH when transmission is not in Park or Neutral, engine speed is between 1600-4400 RPM, TPS indicates closed throttle, and a low airflow condition is sensed. All of these conditions must be met for at least 5 seconds.
2. Before replacing the ECM, MEM-CAL should be checked for correct application.