Easy to follow guide on how an automotive anti-lock brake system works, this information pertains to most vehicles.
The anti-lock brake system (ABS) helps to maintain control and directional stability of an automobile in case of extreme braking circumstances, this is achieved by controlling the rotational speed of each wheel by metering the brake line pressure to each individual wheel.
(Note: if the ABS light is "ON" while driving the anti-lock portion of the system is in bypass mode and will not operate.)
The ABS assembly is made up partially of a central electronic unit, control solenoids
and an electrical connector, during an ABS operation event, one or more of the solenoids
help dump brake line pressure to a particular wheel allowing rotation.
The motor and valve is designed to control fluid to each wheel which can either
add or drop pressure.
The system uses a reluctor-wheel to track rotation which is picked up by a sensor.