The anti-lock braking system on a vehicle is an additional safety feature found on many modern vehicles. The ABS system is designed to help prevent wheels from locking during heavy braking situations, preventing the vehicle from skidding or hydroplaning. The ABS system is made up of the ABS module, and ABS sensors at each wheel. The sensors detect wheel speed, and will send a message to the ABS module to rapidly pump the brakes when it is detected that the vehicle is skidding or has lost traction.
When the ABS system is not functioning then loss of traction, skidding, and hydroplaning are far more likely to occur under heavy braking conditions. The ABS system on most vehicles is usually designed to give you plenty of warning signs when there is any trouble with the system. Being aware of these warning signs, and addressing the problem as soon as they arise will help ensure that your ABS system and vehicle remains functioning for maximum safety.
1. Unresponsive brake pedal
In certain cases, depending on the model of vehicle, when the ABS module fails, the brake pedal may become unresponsive. This is an obvious problem, as an unresponsive brake pedal will not stop a vehicle, or will not be able to do so in an adequately safe manner. In most cases, this will happen slowly, over time. Usually the brake pedal will become increasingly hard to press until it is no longer responsive.
2. Brake pads require more effort to push
When all components of the braking system are working properly, the pedal should require very little effort. It should be very easy to press down on, and once pressed should have an immediately noticeable effect in slowing the vehicle down. If you start to notice that over time the pedal requires increased effort in order to achieve the same amount of braking force, then that may be a sign of a possible issue with the ABS module.
3. The ABS Light is on
The most common sign of an issue with the ABS system is the ABS Light coming on. The ABS Light will show an amber color, and is the equivalent of a Check Engine Light, except it is only to diagnose problems with the ABS system. Older vehicles equipped with earlier ABS systems may not have an ABS Light, and may use a Check Engine Light instead. If the ABS Light comes on then that is a sure sign that there is a problem with the ABS system.
4. The brakes are locking up
When it is functioning correctly the ABS system is designed specifically to prevent the wheels from locking up during heavy braking, preventing loss of traction. However, there can be certain instances where a faulty ABS module can behave erratically, causing your brakes to lock up even under normal driving conditions. If you are experiencing sporadic behavior from your brakes, such as random clicking noises, and/or pumping of the brakes, then the ABS module may need to be replaced.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing ABS Control Module and was authored by Eduardo Ruelas.