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:

    Passing
    More passing distance is needed when towing a trailer. Because the rig is longer, it is necessary to go farther beyond the passed vehicle before returning to the lane. ...

    Gasoline Specifications (U.S. and Canada Only)
    At a minimum, gasoline should meet ASTM specification D 4814 in the United States or CAN/CGSB&-3.5 or 3.511 in Canada. Some gasolines contain an octane-enhancing additive called methylcyclopen ...

    Service Publications Ordering Information
    Service Manuals Service Manuals have the diagnosis and repair information on the engines, transmission, axle, suspension, brakes, electrical, steering, body, etc. Service Bulletins Service Bulletin ...