02 Silverado 1500 speedo reads 100 mph
When does it read 100 mph ? sitting still , all the time etc.... ? The speedometer is controlled by a step motor inside the instrument cluster , step motor is controlled by a microprocessor inside instrument cluster , which get's the speed info from the PCM - engine computer over the vehicle class 2 serial data network . The VSS - vehicle speed sensor is a input to the PCM , this is what the PCM uses to calculate the vehicle speed .
The IPC displays the vehicle speed based on the vehicle speed signal from the PCM. The PCM converts the data from the vehicle speed sensor to a 4000 pulses/mile signal. The IPC uses the vehicle speed signal circuit from the PCM in order to calculate the vehicle speed. The speedometer defaults to 0 km/h (0 mph) if a malfunction in the vehicle speed signal circuit exists.
Having the vehicle hooked up to factory scan tool can take all the guess work out of a diagnoses like this .
Feb 09, 2017 |
2002 Chevrolet Silverado