Most vehicles come equipped with a single warning light to indicate malfunction of the regular brakes, ABS (Anti lock Braking System) malfunction, as well as to indicate that the Parking brake is on.
Possible Root Causes for why the Brake Warning Light might be on:
- Low or leaking brake fluid: Brake fluid is responsible for transferring the force of your foot on the brake pedal to the brake pad, which presses against the discs to stop your car. Without brake fluid, your car cannot brake. If there is brake fluid leakage, your car will soon stop braking altogether. If you’re low on brake fluid, your car’s braking ability will begin to deteriorate. Often low brake fluid goes hand in hand with worn brake pads, because the more the pads are worn, the more fluid is required for the necessary force to be accomplished.
- Parking brake is engaged: As we highlighted in the introduction, in most cars, the brake malfunction warning light is the same as the parking brake ‘on’ light. If your engine is running and the parking brake is engaged, the warning system will let you know by illuminating the brake warning light.
- ABS issue: Most cars have a separate warning light for ABS (anti-lock braking system) problems, but not all do. There’s a chance that a brake warning light could mean trouble with the ABS. ABS systems employ fairly sophisticated technology, where a combination of sensors, processors, and actuators constantly monitor wheel speed, brake pedal status, whether your wheels are locked, and based on some algorithms, decide to pump the brakes in order to provide the ability to steer your car during emergency braking, by not letting the wheels lock up.
- Worn brake pads: When you put your foot on the brake pedal, you are causing the brake pads to press against the brake rotors or drums, which are attached to the spinning wheels. This friction forces the wheels to slow down, and makes your car slow or stop. This constant interaction slowly wears away the pads. Every time you use the brake pedal, you’re wearing another layer off of the pads. When the pads get near the end of their life, your brake light may come on to let you know that it’s time to replace them. However, this warning is mostly found in high end cars. With economy cars, you must rely on a professional to inspect brake wear during every service. If not proactively replaced, a squealing noise might be the only sign that your brakes are completely worn out, and need urgent replacement.