The problem Automobile faces when the ABS speed sensor fail. - Mechdor

Normally, the ABS system faces the problems:-

A vehicle's ABS control module is designed to notify the driver with a warning light if there is a malfunction in the system. Rarely is a malfunction in the module or ABS itself; it is often one or more sensors, or the warning to the sensors. The most common ABS problems occur when sensors become contaminated with debris or metal shavings.

Malfunctions also occur when sensor wiring becomes damaged, resulting in intermittent or no continuity. In more corrosive environments or serious brake system neglect, brake fluid can become contaminated, and the hydraulic control unit fails to function.

If you have a malfunction in the ABS, physically check all wiring and the brake sensors first. When checking the brake sensors, look for metal shavings and other debris that could cause false feedback to the electronic ABS controller. False feedback causes the AMS to trigger when it shouldn't or not function when it should.

They may not have an ABS scan tool at home, but any reputable repair shop will have one, and the scan tool is invaluable if you can't find a physical reason for your ABS issues. After the scan tool produces a fault code, you can proceed with your ABS troubleshooting. Whatever the problem, the repair is much easier once a fault is established.

Symptoms of a Bad or Failed ABS Speed Sensor:-

The anti-lock brake (ABS)  system uses sensors that send data to the ABS module, which will activate it during wheel lock. These sensor mechanisms are installed at the wheel and are usually made up of two components. There will be a reluctor wheel or tone ring seated on the axis, which will spin with the wheel, and either a magnetic or hall effect sensor,r which works together to send data to the ABS control module. Over time, the reluctor wheel may become dirty or damaged to the point where it can no longer provide a consistent reading, or the magnetic/hall effect sensor may fall. When either of these component fall, the ABS system will not function properly and will require service. 

Different cars will have different ABS sensor configurations. Older vehicles may have only one or two sensors on the entire vehicle, while most new ones will have one at each wheel. Individual sensors at each wheel allow for more precise reading and operation; however, it does leave the system prone to more problems. When an ABS sensor falls, there are usually a few warning signs that will warn you that there is a problem.

1. The ABS light comes on:-  The most obvious sign of a problem with the ABS system is that the ABS light will come on. The ABS light is the equivalent of the Check Engine Light, except only for the ABS system. When the light is illuminated, this is usually the first sign that will be displayed, indicating that there may be a problem with the ABS system, and perhaps an issue with one of the system's sensors.
2. Brakes take longer to stop the car:- During heavy braking conditions, the ABS system should automatically activate to aid in slowing down the vehicle, and traction loss and skidding should be minimal. While we should try to practice regular driving habits that avoid heavy braking situations, if you do notice that the vehicle is taking longer to stop under heavy braking situations, or is experiencing traction loss and skidding, then that may be an indicator of there being a problem with the system. The ABS system is typically made up of only a few components- The Module and The Sensors, so problems in its operation will either be with the module or the sensors.
3. Less stability in icy or wet driving conditions:-  Over time, most drivers will become familiar with how their vehicle handles under certain conditions, including slippery conditions, such as driving on wet or icy roads. A properly functioning ABS system will minimise any sort of traction loss, especially under wet or icy roads you experience any sort of tyre slipping or loss of traction for more than a brief moment when stopping or taking off, then the ABS system may not be functioning correctly. This is typically due to either a problem with the module or, more likely, a problem with the sensors.