When an issue crops up with your anti-lock brake system (ABS), a corresponding light will illuminate on the dashboard. The light will show as the acronym “ABS.”
How the ABS system works:
Your ABS exists to keep your vehicle from skidding dangerously during braking. It is an automated safety system that knows when your wheels stop rotating (while your vehicle is still in motion) and releases brake fluid pressure, letting the wheels to continue to rotate. This stops your vehicle from locking up and skidding uncontrollably, and returns the control of the car to you.
Like most systems in your car, your ABS can falter, and you’ll want to resolve the problem as soon as it does.
Common reasons why this happens:
Bad Wheel Speed Sensor
The ABS depends on information from the wheel speed sensors, which are located inside the hub of each wheel and occasionally inside the transmission. These sensors decide the rate at which the wheels are moving, and transfer that information to the ABS. When the ABS gets the information that one or more of the cars’s wheels are moving slower than the others, the system releases brake fluid pressure, which then lets the wheels to resume movement. If the wheel speed sensor is bad, or if the wiring from the sensor to the ABS is bad, then the ABS will not get the wheel speed information that it wants.
The wheel speed sensor is made up of two parts: a metal ring with teeth linked to a drive axle or wheel bearing, and the sensor itself, which reads the teeth on the ring as the wheel rotates. As the wheel speed sensor is found very close to the braking system, the high heat created by the brakes cause the wheel speed sensor to be more susceptible to damage. This in turn makes it one of the more common causes of the ABS light coming on.
Unresponsive Hydraulic Pump or Valve
When the wheel speed sensor tells the ABS that the wheels are moving at different speeds, a hydraulic valve is responsible for releasing, or increasing, the brake fluid pressure to keep the wheels from losing traction with the ground. Like all pumps and valves, those attached to the ABS are liable to become damaged and unresponsive. This may be because of internal wear typically from dirty brake fluid.
Bad ABS Module
Corrosion on the ABS module can prevent information from being relayed between the wheel speed sensor and the ABS. Corrosion is a relatively common problem, and one that can create problems in the aforementioned wheel speed sensor wires. Even a small amount of corrosion can create enough resistance on the wires to keep the system from working. In less common instances, the computer in the module can fail and have to be changed.
Low Fluid Levels
The ABS depends on fluid to help regulate pressure. If the ABS fluid reservoir is low, or if there is too much air in the system, then the ABS will not be able to handle its job.
How ABS repairs is done:
The mechanic will have a scan tool, which lets them to “communicate” to the ABS module to find out what is causing the light to come on. The mechanic will inspect the ABS fuse, and then review the entire ABS system for issues.
How important is this ABS repairs?
If your ABS light turns on, especially if it corresponds with a noticeable reduction in brake performance, shaking, or brake squeaking, then you should stop driving immediately and book a mechanic to diagnose the problem. There is likely an issue with the entire brake system.
SEE ALSO:HOW SPEED SENSORS MAKE THE ABS WORK