2005 Chevrolet Impala Owner's Manual - Page 151

When the ignition is on, the brake system warning light will also come on when you set your parking brake. The light will stay on if your parking brake doesn't release fully. If it stays on after your parking brake is fully released, it means you have a brake 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 on page 4-34. Anti-Lock Brake System Warning Light If your vehicle is equipped with anti-lock brakes, the anti-lock brake system warning light should come on for a few seconds when you turn the ignition key to RUN. If the anti-lock brake system warning light stays on longer than normal after you've started your engine, turn the ignition off or, if the light comes on and stays on when you are driving, stop as soon as possible and turn the ignition off. Then start the engine again to reset the system. If the light still stays on, or comes on again while you are driving, the anti-lock brake system needs service and you do not have anti-lock brakes. The anti-lock brake system warning light should come on briefly when you turn the ignition key to RUN. This is normal. If the light does not come on then, have it fixed so it will be ready to warn you if there is a problem. {CAUTION: Your brake system may not be working properly if the brake system warning light is on. Driving with the brake system warning light on can lead to an accident. If the light is still on after you have pulled off the road and stopped carefully, have the vehicle towed for service. 3-31