Code 24, Vehicle Speed Sensor (VSS): Notes

The speed sensor, which is a Permanent Magnet (PM) generator, provides the control module with vehicle speed information. The PM generator, mounted in the transmission, produces a pulsing voltage signal whenever the vehicle speed is more than 3 MPH. The voltage level and pulses increase with vehicle speed. The control module converts the pulsing voltage to MPH, which is used by the control module in calculations to determine vehicle adjustments.

1. Code 24 will set if VSS signal circuit voltage is constant, engine speed is 1200-4400 RPM, TPS indicates throttle is near idle position, transmission is not in Park or Neutral and all conditions have been met for at least 4 seconds.
2. A voltage of less than one volt at the instrument panel connector indicates that VSS signal circuit wire may be shorted to ground. Disconnect signal wire at the VSS buffer. If voltage remains less than 10 volts, circuit is shorted to ground or open. If circuit is not open or shorted to ground, check for poor control module connection or faulty control module.