Instrument Cluster Description and Operation: Speedometer

The instrument panel cluster (IPC) displays the vehicle speed based on serial data message from the body control module (BCM). The BCM receives vehicle speed data from the PCM/ECM via the serial data circuit. The speedometer will default to 0 km/h (0 mph) if:

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