Home | Mailing
List | Specifications
| Care and Feeding
| Vendors | Literature
Anti-Lock Brake System, Description
BRAKE FLUID CONTAINS POLYGLYCOL ETHERS AND POLYGLYCOLS. AVOID CONTACT
WITH EYES. WASH HANDS THOROUGHLY AFTER HANDLING. IF BRAKE FLUID CONTACTS
EYES, FLUSH EYES WITH RUNNING WATER FOR 15 MINUTES. GET MEDICAL ATTENTION
IF IRRITATION PERSISTS. IF TAKEN INTERNALLY, DRINK WATER AND INDUCE VOMITING.
GET MEDICAL ATTENTION IMMEDIATELY.
Taurus and Sable vehicles have a 4-wheel anti-lock brake system as an
The system operates as follows:
The anti-lock brake system consists of the following major components:
Prevents wheel lockup during an emergency stop by modulating brake pressure.
Permits the driver to maintain steering control and stop the vehicle in
the shortest possible distance under most conditions.
During the anti-lock brake operation, the driver will sense a pulsation
in the brake pedal and a clicking sound.
The pedal effort and pedal feel during normal braking are similar to that
of a conventional power brake system.
Anti-lock brake system (ABS) operates as follows:
front brake anti-lock sensor / rear brake anti-lock sensor.
anti-lock brake control module.
anti-lock brake hydraulic control unit.
Control Module, Anti-Lock Brake
If the anti-lock brake module senses that a wheel is about to lock, based
on brake anti-lock sensor data, it pulses the normally open solenoid valve
closed for that circuit. This prevents any more fluid from entering that
The anti-lock brake module then looks at the brake anti-lock sensor signal
from the affected wheel again.
If that wheel is still decelerating faster than the other three wheels,
it opens the normally closed solenoid valve for that circuit. This dumps
any pressure that is trapped between the normally open valve and the brake
back to the brake master cylinder reservoir.
Once the affected wheel returns to speed, the anti-lock brake module returns
the valves to their normal condition allowing fluid flow to the affected
The anti-lock brake module monitors the electro-mechanical components of
Malfunction of the anti-lock brake system will cause the anti-lock brake
module to shut off or inhibit the system. However, normal power-assisted
Malfunctions are indicated by a warning indicator in the instrument cluster.
The 4-wheel anti-lock brake system is self monitoring. When the ignition
switch is placed in the RUN position, the anti-lock brake module will perform
a preliminary self check on the anti-lock electrical system indicated by
a two second illumination of the amber ABS indicator in the instrument
During vehicle operation, including normal and anti-lock braking, the anti-lock
brake module monitors all electrical anti-lock functions and some hydraulic
In most malfunctions of the anti-lock brake system, the amber ABS indicator
will be illuminated.
Most malfunctions are recorded as a diagnostic trouble code (DTC) in the
anti-lock brake module keep-alive random access memory and assist in pinpointing
the component needing service.
The anti-lock brake control module is located on the hydraulic control
unit located in the front of the engine compartment on the LH side of the
The anti-lock brake control module operates as follows:
Most malfunctions which occur to the anti-lock brake system will be stored
as a diagnostic trouble code (DTC) in the keep-alive random access memory
of the anti-lock brake control module. The DTCs can be retrieved following
the on-board diagnostic procedures.
If the anti-lock brake control module senses that a wheel is about to lock,
the anti-lock brake control module activates the appropriate inlet valve
in the brake pressure control valve block, which closes that valve. This
prevents any more fluid from entering the affected brake.
The anti-lock brake control module then looks at the wheel again. If it
is still decelerating, the anti-lock brake control module opens the normally
closed outlet valve in the brake pressure control valve block, which decreases
the pressure trapped in the line.
Impending wheel lock conditions trigger signals from the anti-lock brake
control module that open and close the appropriate solenoid valves in the
brake pressure control valve block. This results in moderate pulsations
in the brake pedal.
During normal braking, the brake pedal feel will be identical to a standard