Instrument Cluster Description and Operation: Speedometer
The IPC displays the vehicle speed as determined by the ECM. The IPC calculates the mileage based on serial data vehicle speed information from the ECM. The IPC receives vehicle speed information from the BCM via a serial data message. The speedometer defaults to 0 km/h (0 mph) if the IPC detects a loss of serial data communications with the ECM or BCM.