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:

    Tire Designations
    Tire Size The following is an example of a typical passenger vehicle tire size. (A) Passenger (P-Metric) Tire: The United States version of a metric tire sizing system. The letter P as the first ...

    Service Vehicle Messages
    SERVICE AC SYSTEM This message is displayed if there is a problem with the air conditioning system. Take the vehicle to your dealer for service. SERVICE POWER STEERING This message is displayed i ...

    Ultrasonic Parking Assist
    If available, Ultrasonic Rear Parking Assist (URPA) system uses sensors on the rear bumper to assist with parking and avoiding objects while in R (Reverse). It operates at speeds less than 8 km/h (5 m ...