GM Service Manual Online
For 1990-2009 cars only

The trip odometer can record the number of miles, used in the United States, or kilometers, used in Canada, traveled for up to two trips.

Cycle between the odometer and trip odometers A and B by pressing the reset button located in the lower right area of the speedometer. Press the reset button to tell how many miles or kilometers have been recorded on either Trip A or Trip B since the trip odometer was last set back to zero.

To reset each trip odometer to zero, press and hold the reset button. The reset button resets only the trip odometer that is being displayed. Each trip odometer must be reset individually.