Circuit/System Description
WARNING: This page is about a different car, the 2007 Suzuki XL7. However, it is still accessible from the selected car via links, so may be relevant.
The instrument panel cluster (IPC) displays the vehicle speed based on the information from the engine control module (ECM). The ECM converts the data from the vehicle speed sensor to a 4000 pulses/mile signal. The ECM sends the vehicle speed information via high speed GMLAN serial data circuit to the body control module (BCM). The BCM then sends the information via low speed GMLAN to the IPC to order to display the vehicle speed and miles traveled.