When the ignition is on, the brake system warning light will come on when you set your parking brake. The light will stay on if your parking brake does not release fully. If it stays on after your parking brake is fully released, it means your vehicle has a brake problem. A chime may also sound when the light comes on.
Your vehicle's hydraulic brake system is divided into two parts. If one part is not working, the other part can still work and stop you. For good braking, though, you need both parts working well.
If the warning light comes on, there could be a brake problem. Have your brake system inspected right away.
This light should come on briefly when you turn the ignition key to ON/RUN. If it does not come on then, have it fixed so it will be ready to warn you if there is a problem.
If the light comes on while you are driving, pull off the road and stop carefully. You may notice that the pedal is harder to push or the pedal may go closer to the floor. It may take longer to stop. If the light is still on, have the vehicle towed for service. See Towing Your Vehicle.
Caution: 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.