Odometer: Description and Operation

ODOMETER

The odometer is an electronic digital display. Digits displayed are illuminated by the odometer backlight bulb. The odometer backlight bulb brightness is controlled by class 2 messages from the BCM to adjust the display for daylight and instrument panel dimming operation. The trip odometer and total odometer will show in this display area. The push button in the lower right side of the speedometer is used to toggle between the trip and total odometer readings. To reset the trip odometer, push and hold the button down for at least two seconds. The total odometer display has six digits with no decimal display. The trip odometer has four digits including a decimal point and indicates tenths of a mile or kilometer.

The body control module (BCM) stores the vehicle mileage. If the BCM fails, the cluster will display the last valid mileage that was sent before the BCM failed. For replacement of the BCM refer to BCM. Replacement instrument clusters do not require odometer pre-setting before installation. If the instrument cluster is replaced, the mileage stored in the BCM will be sent to the new cluster via serial data, and shown in the odometer display.

The BCM calculates vehicle mileage from rolling count data sent to the BCM by a CAN message from the ECM (L81) or a class 2 message from the PCM (L61). The BCM sends the mileage data to the cluster over serial data to display the vehicle mileage. The actual mileage is located in the BCM. All calculations for odometer are performed in the BCM.