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:

    Rear Climate Control System (Rear Climate with Rear Seat Audio)
    A. Fan Control B. Air Delivery Mode Control C. Temperature Control For vehicles with the rear climate control system, the controls are located on the rear of the center console. Press the REAR b ...

    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 ...

    Safety Locks
    The vehicle has rear door security locks to prevent passengers from opening the rear doors from the inside. Open the rear doors to access the security locks on the inside edge of each door. To set ...