GM Service Manual Online
For 1990-2009 cars only

The Transmission Scan Tool Data Definitions contain a brief description of manual transmission related parameters available on the scan tool. The list is in alphabetical order.

Vehicle Speed Sensor: The vehicle speed sensor signal is converted into km/h (mph) for display. The vehicle speed output from the PCM is 4,000 pulses per mile (ppm). The scan tool uses the Class 2 serial data from the PCM to obtain vehicle speed, while the instrument panel cluster, cruise control module and multi-function alarm module use the 4,000 ppm output.