System Operation: Speedometer

The IPC  receives the vehicle speed data from the BCM  over the Medium Speed Controller Area Network (MS-CAN). The BCM  receives the vehicle speed message from the GWM  over the High Speed Controller Area Network (HS-CAN). The GWM  receives the vehicle speed data from the ABS  module over the Electric Vehicle (EV) High Speed Controller Area Network (HS-CAN). The ABS  module uses tire size stored in the vehicle configuration file along with wheel speed inputs to generate a vehicle speed signal.

The IPC  provides a tolerance that allows the speed indication to display between 3% below and 7% above the actual vehicle speed. This means that with an actual vehicle speed of 97 km/h (60 mph), the speedometer can indicate between 94-103 km/h (58-64 mph). Incorrect tire size or tire size configuration could potentially affect the speedometer accuracy.