Isuzu 1999 RODEO Workshop Manual page 383

BRAKE CONTROL SYSTEM
5A–8
Pressure Increase (Re-apply)
The re-apply sequence is initiated to achieve optimum
braking. The isolation valve is momentarily opened to
allow master cylinder and pump pressure to reach the
brakes. This controlled pressure rise continues until the
wheel is at optimum brake output or until the brake
pressure is brought up to the master cylinder output
pressure.
Legend
(1) Brake
(2) Master Cylinder
If more pressure is required, more fluid is drawn from the
master cylinder and applied to the brakes. The driver may
feel slight pedal pulsations, or pedal drop, this is normal
and expected.
As fluid is re-applied to the brakes, the wheel speed will
reduce. If the wheels approach imminent lockup again,
the module will isolate, dump and re-apply again. This
cycle occurs in millisecond intervals, allowing several
cycles to occur each second. It is a much faster and more
controlled way of "pumping the pedal".
C05RW014