See also:

Cellular and GPS Antennas
Avoid placing items over or near the antenna to prevent blocking cellular and GPS signal reception. Cellular reception is required for OnStar to send remote signals to the vehicle. ...

Roof Rack System
WARNING If something is carried on top of the vehicle that is longer or wider than the roof rack—like paneling, plywood, or a mattress—the wind can catch it while the vehicle is being driven. The ...

Reporting Safety Defects to the Canadian Government
If you live in Canada, and you believe that the vehicle has a safety defect, notify Transport Canada immediately, and notify General Motors of Canada Limited. Call Transport Canada at 1-800-333-0510 o ...