Anti-Lock Brake System (Abs)

During braking if a wheel starts to lock-up, a wheel speed sensor will transmit a signal to the brake control modulator which will start the hydraulic pump. The brake control modulator will close the input valve for the brake line connected to the locking-up wheel. This will stop any increase in brake fluid pressure to the brake caliper. If this does not stop wheel from locking-up, the brake control modulator will open a return valve to decrease brake pressure to affected wheel until wheel begins to accelerate again. When brake control modulator opens a return valve, brake fluid is directed into a low pressure accumulator which is housed in pump. Fluid from the low pressure accumulator is pumped through a damping chamber to brake master cylinder. Brake pressure to brake caliper will be increased in small increments to maintain maximum braking force. This is done by closing the return valve, opening the input valve and using the hydraulic pump to increase brake pressure.

The ABS system uses 4 wheel speed sensors which monitors wheel speed separately. Even though each wheel is monitored separately, the rear wheels are controlled as a pair. If one rear wheel speed sensor begins to detect wheel slippage, brake pressure is reduced to both rear wheels.Fluid pressure is controlled by the rear wheel having the least adhesion.

If a problem is detected in the ABS system, a warning light will illuminate on the instrument panel to notify the driver of a system problem. The brake system will continue to work as a conventional brake system.