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) calculates the mileage based on the vehicle speed signal circuit from the powertrain control module (PCM). The PCM sends the vehicle speed information via high speed GMLAN serial data to the body control module (BCM). The BCM then sends the information via low speed GMLAN to the IPC indicating the value of the odometer. The odometer will display 'error' if an internal memory failure is detected. The odometer displays either miles or kilometers and the desired units can be accessed by pressing the trip/reset switch.