GM Service Manual Online
For 1990-2009 cars only

The navigation system determines the position of your vehicle by using satellite signals, various vehicle signals, and map data.

At times, other interferences such as the satellite condition, road configuration, the condition of the vehicle and/or other circumstances can interfere with the navigation system's ability to determine the accurate position of the vehicle.

The GPS shows the current position of your vehicle using signals sent by the GPS Satellites of the United States Department of Defense. When your vehicle is not receiving signals from the satellites, a symbol appears on the map screen. Refer to Symbols.

This system may not be available or interferences may occur if any of the following are true:

    • Signals are obstructed by tall buildings, trees, large trucks, or a tunnel.
    • Objects are located on the rear shelf of the vehicle.
    • Satellites are being repaired or improved.
    • After-market glass tinting has been applied to the vehicle's rear windshield.

Notice: Do not apply after-market glass tinting to the vehicle's windows. Glass tinting interferes with the system's ability to receive GPS signals and causes the system to malfunction. The window might have to be replaced to correct the problem. This would not be covered by the warranty.

For more information if the GPS is not functioning properly, see If the System Needs Service and Problems with Route Guidance.