See also:

Brake System Warning Light
With the ignition on, the brake system warning light comes on when the parking brake is set. If the vehicle is driven with the parking brake engaged, a chime sounds when the vehicle speed is greater t ...

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 ...

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 vehic ...