Chrysler Concorde 1993 Service Manual page 178

5 - 84 ANTI-LOCK BRAKE SYSTEM
Fig. 8 Main Relay And Pump/Motor Relay
PUMP/MOTOR RELAY
The Pump/Motor Relay (Fig. 8) supplies power to
the pump/motor. It is attached to the outside of the
Power Distribution Center (PDC). The relay coil is
powered by the System Relay and the coil ground is
controlled by the (CAB).
The Pump/Motor Relay is a special four terminal
relay and should not be replaced with a standard re-
lay. If either relay is defective both relays must be
replaced. They are serviced as an assembly.
Fig. 1 Brakes Released - Hydraulic Control
HYDRAULIC CIRCUITS AND VALVE OPERATION
Through the following operation descriptions and
diagrams. The function of the various hydraulic con-
trol valves in the ABS system will be described. The
fluid control valves mentioned below, control the flow
of pressurized brake fluid to the wheel brakes during
the different modes of Anti-Lock braking.
The following hydraulic circuit drawings are only a
representation of the actual hydraulic circuits. Note
that only the valves for the right front wheel brake
are shown actuated for the various modes.
BRAKES RELEASED
When the brake pedal is released, all pressures in the
system are the same (Fig. 1) (at atmospheric pressure).
BASELINE BRAKES
The Baseline Brake System is a diagonal split
brake system. In a diagonal split brake system the
master cylinder primary circuit supplies pressure to
the right front and left rear wheel brakes. The mas-
ter cylinder secondary circuit supplies pressure to the
left front and right rear wheel brakes (Fig. 2).
ABS BRAKING-PRESSURE HOLD
During an Anti-Lock stop, if a wheel speed sensor in-
dicates a wheel locking tendency. The normally open in-
let valve (Fig. 3) is cycled closed by the (CAB). This will
prevent any additional pressure from being applied to
the wheel brake.