BOSCH ABS 5.0

An anti-lock braking systems main job is to keep the brakes from locking up allowing the driver to stop in the shortest distance and still keep proper steering control. It consists of four main components:

• Speed sensors: Reads the wheel speed of all 4 wheels and uses a comparison between them to detect when one or more wheels are locking.
• Valves: Depending on the type of system there can be up to 2 valves for each wheel, the first valve is an inlet valve which is normally open to allow pressure to move from the pedal to the brake and closes when skidding is detected to stop further pressure being applied. The second is an outlet valve which is normally closed to allow the brakes to operate and then opens to release pressure on a locked wheel. More sophisticated systems also have demanual valves to seal the pedal from the rest of the system to stop it shuddering and sinking as the other valves open and close.
• Pump: Puts the pressure back when the valve is releasing the pressure.
• ABS control module (ECU): Reads the information from the speed sensors and sends commands to the valves.