System Operation: Speedometer

The PCM calculates the vehicle speed from the transmission OSS  sensor input and from the tire size and axle ratio configuration in the PCM VID  block. The PCM provides the IPC  with a vehicle speed data message to command the speedometer pointer.

The IPC  provides a tolerance which allows the gauge to display between 3% lower and 7% higher than the actual vehicle speed. This means that with an actual vehicle speed of 96.6 kmh (60 mph), the speedometer may indicate between 93.7 kmh (58.2 mph) and 103.3 kmh (64.2 mph), which is normal.