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:

    Resuming a Set Speed
    If the cruise control is set at a desired speed and then the brakes are applied, the cruise control is disengaged without erasing the set speed from memory. Once the vehicle speed reaches about 40 km ...

    If Steam is Coming from the Engine Compartment
    WARNING Steam from an overheated engine can burn you badly, even if you just open the hood. Stay away from the engine if you see or hear steam coming from it. Just turn it off and get everyone aw ...

    Vehicle Speed Messages
    SPEED LIMITED TO XXX MPH (KM/H) This message displays when your vehicle speed is limited to 128 km/h (80 mph) because the vehicle detects a problem in the speed variable assist steering system. Have ...