Instrument Panel Cluster (IPC) Description and Operation: Speedometer

The instrument panel cluster (IPC) displays the vehicle speed based on the information from the engine control module (ECM)/powertrain control module (PCM). The ECM/PCM calculates the vehicle speed based on the class 2 message indicating the wheel reference speed from the electronic brake control module (EBCM) if:

• The ECM/PCM detects a malfunction in the vehicle speed sensor circuit.
• The IPC detects a loss of class 2 communications with the ECM/PCM.

The speedometer defaults to 0 km/h (0 mph) if the IPC detects a loss of class 2 communications with both the ECM/PCM.