GM Service Manual Online
For 1990-2009 cars only

Your speedometer lets you see your speed in both miles per hour (mph) and kilometers per hour (km/h). Your odometer shows how far your vehicle has been driven, in either miles (used in the United States) or kilometers (used in Canada).

Your odometer can be seen when the vehicle is running. To view it when the ignition is off, press the trip odometer button located near the display. The mileage will display for about five seconds.