Ford Ranger Owner's Manual page 158

NOTE: If a fault occurs in the anti-lock system, and the brake
warning light is not lit, the anti-lock system is
disabled but normal brake function remains
operational.
Four Wheel Anti-lock Brake System
Your vehicle may be equipped with a Four Wheel Anti-lock
Braking System (4WABS). The 4WABS helps the driver to
maintain vehicle control by preventing wheel lockup during
hard braking.
The 4WABS operates with a computer that is able to optimize
vehicle control during braking on varying tire and road
conditions by modulating the brake pressure at each of the front
wheels and the rear axle. This "pumping action" is similar to
the driver "pumping" the brakes but happens at a much faster
rate.
The Anti-lock system does NOT assist the vehicle in
stopping quickly on wet or icy surfaces. Heavy braking
combined with poor road conditions could cause you to
lose steering control of your vehicle.
Using anti-lock brakes
The operation of a vehicle with 4WABS is not similar to the
operation of normal brakes. Some differences exist and are listed
below:
Apply the brake steadily. In the event of a panic stop, do
NOT "pump" the brakes. "Pumping" the brakes during an
Anti-lock stop will diminish braking effectiveness.
During an Anti-lock stop, the driver will notice a brake
pedal pulsation and hear some noise from the engine
compartment. This is an indication that the 4WABS system is
working correctly and is normal.
WARNING
Driving
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