The vehicle's hydraulic brake system is divided into two parts. If one part is not working, the other part can still work and stop the vehicle. For good braking both parts need to be working.
If the warning light comes on, there is a brake problem. Have the brake system inspected right away.
This light should come on briefly when the engine is started. If it does not come on then, have it fixed so it will be ready to warn if there is a problem.
When the ignition is on, the brake system warning light also comes on when the parking brake is set. The light will stay on if the parking brake does not fully release . If it stays on after the parking brake is fully released, it means there is a brake problem.
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.
If the light comes on while driving, pull off the road and stop carefully. The pedal can be harder to push, or the pedal could go closer to the floor. It could take longer to stop. Try turning off and restarting the vehicle one or two times, if the light is still on, have the vehicle towed for service. See Towing Your Vehicle .