Instrument Panel Cluster (IPC) Description and Operation: Speedometer
WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The IPC displays the vehicle speed based on the information from the BCM. The ECM calculates the vehicle speed based on the CAN serial data message indicating the wheel reference speed from the EBCM. The ECM sends a CAN serial data message to the BCM indicating the vehicle speed. The BCM sends a class 2 message to the IPC indicating the vehicle speed.
The speedometer defaults to 0 km/h (0 mph) when any of the following occur:
- The EBCM detects a malfunction in the vehicle speed sensor circuit.
- The ECM detects a loss of CAN communications with the EBCM.
- The BCM detects a loss of CAN communications with the ECM.
- The IPC detects a loss of class 2 communications with the BCM.