Diagnostics

OnStar Vehicle Diagnostics will perform a vehicle check every month. It will check the engine, transmission, antilock brakes, and major vehicle systems. It also checks the tire pressures, if the vehicle is equipped with the Tire Pressure Monitoring System. If a diagnostics check is needed between e-mails, push OnStar Additional Information, and an Advisor can run a check.

    See also:

    Towing with a Stability Control System
    When towing, the sound of the stability control system might be heard. The system is reacting to the vehicle movement caused by the trailer, which mainly occurs during cornering. This is normal when t ...

    Connecting a USB Storage Device or iPod®
    The USB port can be used to control an iPod or a USB storage device. To connect a USB storage device, connect the device to the USB port located in the center console or on the instrument panel. To ...

    Customer Assistance Offices (U.S. and Canada)
    GMC encourages customers to call the toll-free number for assistance. However, if a customer wishes to write or e-mail GMC, the letter should be addressed to: United States GMC Customer Assistance ...