Speedometer

The speedometer is an analog gauge that is located in the instrument cluster. The VCM sends vehicle speed pulses to the instrument cluster on a designated circuit.

The speedometer system consists of the instrument cluster, Vehicle Speed Sensor (VSS), VCM and related wiring. Repairs to the instrument cluster can only be performed by an authorized instrument cluster service center.

The VCM converts the analog output from the vehicle speed sensor to a digital signal containing 4,000 pulses. per mile (PPM) for the instrument cluster. The VCM is matched to the final drive and tire size of each vehicle. If the final drive or tire size is changed for any reason, the VCM must be updated in order to match the new final drive or tire size. If not, the signal will not be accurate for proper speedometer odometer operation. An incorrect signal can affect the antilock brakes and the cruise control systems.

The VSS is a permanent magnet signal generator that sends an analog signal proportional to the propeller shaft speed to the VCM. The VSS mounts to the transmission tailshaft extension housing on Rear Wheel Drive (RWD) models and the transfer case output shaft housing on All Wheel Drive (AWD) models.