Chrysler Crossfire. Manual — part 109
INSTALLATION
The solenoid valve is part of the brake booster assembly. Refer to the brake booster installation procedure (Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/POWER BRAKE BOOSTER - INSTALLATION) .
RELEASE SWITCH
DESCRIPTION
The BAS release switch (2) is a device used to signal the Controller Antilock Brake (CAB) module that the brake is
released.
The BAS release switch (2) cannot be serviced. The power brake booster must be replaced in the event of a BAS
release switch failure.
OPERATION
When the force on the brake pedal is removed, movement on the brake booster control valve occurs. When this
occurs, the signal is sent to the Controller Antilock Brake (CAB) Module.
REMOVAL
The release switch is part of the brake booster assembly. Refer to the brake booster removal procedure (Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/POWER BRAKE BOOSTER - REMOVAL).
INSTALLATION
The release switch is part of the brake booster assembly. Refer to the brake booster installation procedure (Refer to
5 - BRAKES/HYDRAULIC/MECHANICAL/POWER BRAKE BOOSTER - INSTALLATION).
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BRAKES - ABS SERVICE INFORMATION
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HYDRAULIC/MECHANICAL
STANDARD PROCEDURE - BLEEDING ABS BRAKE SYSTEM
The base brake’s hydraulic system must be bled anytime air enters the hydraulic system (Refer to 5 - BRAKES -
STANDARD PROCEDURE) .
HCU (HYDRAULIC CONTROL UNIT)
DESCRIPTION
The CAB (Mark 20
T
or Mark 25
T
) is a microprocessor-
based device which monitors the Antilock Brake Sys-
tem (ABS), and the Electronic Stability Program (ESP)
during normal braking and driving functions. The CAB
controls brake pressure when the vehicle is in an ABS
stop, or if the vehicle is in a spin. The CAB is mounted
to the Hydraulic Control Unit (HCU) (3) as part of the
Integrated Control Unit (ICU). The CAB uses a 47-way
electrical connector on the vehicle wiring harness. The
power source for the CAB is through the 50 amp fuse
located in the Engine Fuse Block (2).
OPERATION
All switching components of the ABS system are combined in the ABS hydraulic unit. A 2/2-way valve for build-up/
hold pressure or hold/reduce pressure functions is used on each wheel for control. At the rear, the same valves are
used for both wheels. The return pump integrated in the hydraulic unit is used to return the brake fluid during the
pressure reduction phase.
An increase in pressure compared to the pressure controlled by the master brake cylinder is not possible during the
ABS control phase. A muffler is fitted for each brake circuit to reduce delivery noise. During the ABS pressure reduc-
tion phase, the brake fluid flows back to the return pumps via the low-pressure accumulators.
NORMAL BRAKING FUNCTION
When the driver is applying the brake pedal during a no wheel spin or slip situation, the vehicle builds pressure in
the brake hydraulic system to engage the brakes and stop the vehicle. The hydraulic shuttle valve internal to the
ICU closes with every brake pedal application so pressure is not created at the inlet to the pump/motor and the
vehicle stops normally.
ABS BRAKING FUNCTION
During a stop where one wheel is slipping because the driver is attempting to stop the vehicle at a faster rate than
is allowed by the surface on which the tires are riding, the hydraulic shuttle valve closes upon brake application so
that the pump/motor cannot siphon brake fluid from the master cylinder. The normally open and normally closed
valves modulate (build/decay) the brake hydraulic pressure as required. The pump/motor is switched on so that the
brake fluid from the low pressure accumulators is returned to the master cylinder circuits. The brake fluid is routed
to either the master cylinder or the wheel brake, depending on the position of the normally open valve.
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BRAKES - ABS SERVICE INFORMATION
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ABS TRACTION CONTROL FUNCTION
The vehicle in the traction control TC (ASR) mode. If the drive wheel is spinning and brake pressure is required to
reduce its speed. The normally open TC (ASR) valve is energized to isolate the brake fluid being pumped from the
master cylinder and to isolate the driven wheel. The normally open TC (ASR) valve bypasses the pump output back
to the master cylinder at a fixed pressure setting. The normally open and normally closed valves modulate (build/
decay) the brake pressure as required to slow the spinning wheel.
REMOVAL
1. Clean off the top of the HCU, especially around the
hydraulic lines (1-6). Be sure there is not any
debris that could fall into the brake line holes.
Note: To aid in reassembly, insure the hydraulic
brake lines and corresponding connections at the
HCU are clearly marked before disassembly.
2. Remove the hydraulic lines from the HCU. Seal off
the hydraulic lines and connections with suitable
plugs.
•
Right rear wheel (1)
•
Master cylinder front (2)
•
Right front wheel (3)
•
Left front wheel (4)
•
Left rear wheel (5)
•
Master cylinder rear (6)
3. Disconnect the hydraulic controller unit harness
connector (1) from the CAB.
4. Remove the HCU upwards, by carefully pushing
the hydraulic lines to one side and carefully pull up.
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BRAKES - ABS SERVICE INFORMATION
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INSTALLATION
1. Inspect the seating and condition of the rubber
grommets and replace if necessary.
CAUTION:
Use
caution
when
re-connecting
hydraulic lines. Refer to markings for proper
installation. If necessary, trace the line routing to
the corresponding wheel.
2. Install the brake lines (1-6). Pay very close atten-
tion to the locations when installing the hydraulic
lines. DO NOT cross thread.
•
Right rear wheel (1)
•
Master cylinder front (2)
•
Right front wheel (3)
•
Left front wheel (4)
•
Left rear wheel (5)
•
Master cylinder rear (6)
3. Connect the hydraulic control unit harness connec-
tor (1) to the CAB.
4. Bleed the brake system. (Refer to 5 - BRAKES -
STANDARD PROCEDURE).
5. Connect the DRB III
T
and read any DTCs, then
clear any applicable codes.
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BRAKES - ABS SERVICE INFORMATION
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