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 an Advisor can run a check., and an Advisor can run a check.

    See also:

    Ignition Positions
    The ignition switch has four different positions. To shift out of P (Park), the ignition must be in ON/RUN or ACC/ ACCESSORY and the regular brake pedal must be applied. A (STOPPING THE ENGINE/ ...

    Leaving the Vehicle With the Engine Running (Automatic Transmission)
    WARNING! It can be dangerous to leave the vehicle with the engine running. The vehicle could move suddenly if the shift lever is not fully in P (Park) with the parking brake firmly set. And, ...

    Trailer Sway Control (TSC)
    Non-hybrid vehicles with StabiliTrak have a Trailer Sway Control (TSC) feature. If the vehicle is towing a trailer and the system detects that the trailer is swaying, the vehicle brakes are applie ...