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:

    Leaving the Vehicle With the Engine Running
    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, if yo ...

    Interior
    The Sierra showcases two different interior designs. Work Truck and SLE models are more utility-minded, with large controls and door handles that can be operated while wearing gloves. The SLT offe ...

    Treadwear 200 Traction AA Temperature A
    The following information relates to the system developed by the United States National Highway Traffic Safety Administration (NHTSA), which grades tires by treadwear, traction, and temperature perfor ...