Brake System Warning Light
The vehicle brake system consists of two hydraulic circuits. If one circuit is not working, the remaining circuit can still work to stop the vehicle. For normal braking performance, both circuits need to be working.
If the warning light comes on, there is a brake problem. Have the brake system inspected right away.

The Brake System Warning Light should come on briefly as the engine is started. If it does not come on, have the vehicle serviced by your dealer.
WARNING
The brake system might not be working properly if the brake system warning light is on.
Driving with the brake system warning light on can lead to a crash. If the light is still on after the vehicle has been pulled off the road and carefully stopped, have the vehicle towed for service.
If the light comes on while driving, a chime sounds. Pull off the road and stop. The pedal might be harder to push or go closer to the floor.
It might also take longer to stop.
If the light is still on, have the vehicle towed for service. See Towing the Vehicle .
See also:
When to Add Engine Oil
If the oil is below the cross-hatched area at the tip of the dipstick, add 1
L (1 qt) of the recommended oil and then recheck the level. See “Selecting the Right
Engine Oil” in this section ...
Your Responsibility
Increase the volume of the radio if the OnStar Advisor cannot be heard.
If the light next to the OnStar buttons is red, the system may not be functioning properly. Push and request a vehicle diagnos ...
Radio(s)
VOL/ : Press to turn the system
on and off. Turn to increase or
decrease the volume.
RADIO/BAND or SOURCE: Press
to choose between FM, AM,
or XM™, if equipped.
Menu Knob: Turn to select r ...
