2000 DODGE NEON tra

PARKING BRAKE LEVER
WARNING: THE AUTOMATIC ADJUSTING FEATURE
OF THIS PARKING BRAKE LEVER CONTAINS A
CLOCK SPRING LOADED TO APPROXIMATELY 25
POUNDS. DO NOT RELEASE THE AUTOMATIC
ADJUSTER LOCKOUT DEVICE UNLESS THE REAR
PARKING BRAKE CABLES AND EQUALIZER ARE
CONNECTED TO THE LEVER OUTPUT CABLE.
KEEP HANDS OUT OF AUTOMATIC ADJUSTER
SECTOR AND PAWL AREA. FAILURE TO OBSERVE
CAUTION IN HANDLING THIS MECHANISM COULD
LEAD TO SERIOUS INJURY.
WARNING: WHEN REPAIRS TO THE PARKING
BRAKE LEVER OR CABLES ARE REQUIRED, THE
AUTOMATIC ADJUSTER MUST BE LOADED AND
LOCKED OUT TO AVOID POSSIBLE INJURY. THE
LEVER ADJUSTMENT MECHANISM CAN BE
LOADED AND LOCKED OUT AS OUTLINED IN THIS
PROCEDURE.
REMOVAL
(1) Block the tire and wheels so the vehicle does
not move once the vehicle parking brake lever is
released.
(2) Fully apply the parking brake lever, then shift
the transmission into neutral.
(3) Remove the screws attaching the center con-
sole, then remove the center console.
(4) Lower the parking brake lever handle to the
released position.
(5) Grasp the parking brake lever output cable by
hand and pull upward. Continue pulling on the cable
until a pin punch can be inserted through the hole in
the lever mechanism sector gear and the hole in the
right side of its mounting bracket (Fig. 93). This will
lock the parking brake automatic adjustment mecha-
nism in place and take tension off the parking brake
cables.
(6) Remove both rear parking brake cables from
the parking brake cable equalizer (Fig. 94).
(7) Remove the wiring harness electrical connector
from the parking brake warning lamp switch on the
parking brake lever (Fig. 95).
(8) Remove the two nuts attaching the parking
brake lever to the vehicle (Fig. 95).
(9) Remove the parking brake lever from the vehi-
cle.
Fig. 93 Pin Punch Installed
1 ± PARKING BRAKE LEVER
2 ± PIN PUNCH
3 ± OUTPUT CABLE
Fig. 94 Parking Brake Cables At Equalizer
1 ± LEVER OUTPUT CABLE
2 ± EQUALIZER
3 ± REAR PARKING BRAKE CABLES
5 - 48 BRAKESPL
REMOVAL AND INSTALLATION (Continued)

INSTALLATION
(1) Place the parking brake lever on the mounting
studs on the vehicle floor. Install and tighten the two
mounting nuts to a torque of 28 N´m (250 in. lbs.)
(Fig. 95).
(2) Connect the wiring harness electrical connector
on the parking brake warning lamp switch (Fig. 95).
(3) Install both rear park brake cables into the
equalizer on the parking brake lever output cable
(Fig. 94).
(4) Ensure that the parking brake cables are cor-
rectly installed on the equalizer and aligned with the
cable track on the parking brake lever.
NOTE: The parking brake lever can only be in the
released position when releasing the automatic
adjuster.
(5) Keeping your hands clear of the automatic
adjuster sector and pawl area, firmly grasp the park-
ing brake lever pin punch (or locking pin if a new
mechanism has been installed) (Fig. 93), then quickly
remove it from the parking brake lever mechanism.
This will allow the park brake lever mechanism to
automatically adjust the parking brake cables.
(6) Cycle the parking brake lever once to position
the parking brake cables, then return the parking
brake lever its released position.
(7) Check the rear wheels of the vehicle. They
should rotate freely without dragging with the lever
in its released position.
(8) Fully apply the parking brake lever.
(9) Install the center console and its mounting
screws.
(10) Remove the blocks from the tires and wheels.
PARKING BRAKE CABLE (REAR)
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
The procedure below applies to either of the two
rear parking brake cables.
REMOVAL
(1) Block the tire and wheels so the vehicle does
not move once the vehicle parking brake lever is
released.
(2) Fully apply the parking brake lever, then shift
the transmission into neutral.
(3) Remove the screws attaching the center con-
sole, then remove the center console.
(4) Lower the parking brake lever handle to the
released position.
(5) Grasp the parking brake lever output cable by
hand and pull upward. Continue pulling on the cable
until a pin punch can be inserted through the hole in
the lever mechanism sector gear and the hole in the
right side of its mounting bracket (Fig. 93). This will
lock the parking brake automatic adjustment mecha-
nism in place and take tension off the parking brake
cables.
(6) Remove both rear parking brake cables from
the parking brake cable equalizer (Fig. 94).
(7) Remove the rear seat cushion from the vehicle.
(8) Fold the rear carpeting forward to expose the
parking brake cables at the end of the rear floor.
(9) Install the box end of a 1/2 inch wrench over
the parking brake cable retainer (Fig. 96). Push the
wrench onto the retainer until the retainer fingers
are collapsed. From under the carpeting, grasp the
parking brake cable housing and pull cable straight
out of the bracket attached to the floor.
(10) Raise the vehicle. Refer to HOISTING in the
LUBRICATION AND MAINTENANCE group for the
proper lifting procedure.
(11) Remove the rear tire and wheel assembly
from the vehicle.
(12) On vehicles equipped with rear drum brakes,
remove the brake drum. Refer to BRAKE DRUM in
this section of this service manual group.
(13) On vehicles equipped with rear disc brakes:
²Remove the disc brake caliper guide pin bolts,
then the caliper from disc brake adapter (Fig. 97).
²Hang the caliper out of the way using a wire
hanger or cord.
²Remove the brake rotor from the rear hub and
bearing.
(14) Remove the dust cap from the rear hub and
bearing.
Fig. 95 Parking Brake Lever
1 ± MOUNTING NUTS
2 ± PARKING BRAKE LEVER
3 ± PARKING BRAKE WARNING LAMP SWITCH CONNECTOR
PLBRAKES 5 - 49
REMOVAL AND INSTALLATION (Continued)

(3) Install the parking brake cable into the brake
support plate or the rear disc brake adapter. Be sure
the locking fingers on the cable retainer are
expanded once the cable is pushed all the way into
the support plate or brake adapter hole to ensure the
cable is securely held in place.
(4) On vehicles equipped with rear drum brakes:
²Install the parking brake cable on the parking
brake cable actuating lever (Fig. 99).
²Install the actuating spring to the brake shoe
and the brake adjustment lever (Fig. 100).
(5) On vehicles equipped with rear disc brakes:²Install the parking brake shoes actuator lever on
the parking brake cable (Fig. 102).
²Install the parking brake shoe assemblies on the
disc brake adapter (Fig. 98).
(6) Install the hub and bearing on the rear spin-
dle. Install a new hub and bearing retaining nut.
Tighten the retaining nut to a torque of 217 N´m
(160 ft. lbs.).
(7) Install the hub and bearing dust cap.
(8) On drum brake equipped vehicles, install the
rear brake drum.
(9) On vehicles equipped with rear disc brakes,
install the brake rotor, then the disc brake caliper
(Fig. 97). Install the two caliper guide pin bolts, then
tighten them to a torque of 22 N´m (192 in. lbs.).
(10) Install the rear tire and wheel assembly.
Tighten all wheel nuts to a torque of 135 N´m (100 ft.
lbs.).
(11) Lower the vehicle.
(12) Ensure that the seal grommet on the cable
that was installed from underneath is fully seated
into the floor pan.
(13) Route the parking brake cable under the car-
peting, up to parking brake cable retaining bracket
on floor pan. Install the parking brake cable through
the retaining bracket. Push the cable in until the
locking fingers on the cable retainer lock the cable
into place.
(14) Install the rear parking brake cables into the
equalizer on the parking brake lever output cable
(Fig. 94).
(15) Ensure that the parking brake cables are cor-
rectly installed on the equalizer and aligned with the
cable track on the parking brake lever.
NOTE: The parking brake lever can be in any posi-
tion when releasing the automatic adjuster.
(16) Keeping your hands clear of the automatic
adjuster sector and pawl area, firmly grasp the park-
ing brake lever pin punch (or locking pin if a new
mechanism has been installed) (Fig. 93), then quickly
remove it from the parking brake lever mechanism.
This will allow the park brake lever mechanism to
automatically adjust the parking brake cables.
(17) Cycle the parking brake lever once to position
the parking brake cables, then return the parking
brake lever its released position.
(18) Check the rear wheels of the vehicle. They
should rotate freely without dragging with the lever
in its released position.
(19) Reposition the rear carpeting into place.
(20) Install the rear seat cushion. Be sure the seat
cushion is fully installed in the retainers on the floor
pan of the vehicle.
(21) Fully apply the parking brake lever.
Fig. 103 Parking Brake Cable Removal
1 ± CABLE RETAINER
2 ± OFFSET BOX WRENCH
3 ± PARKING BRAKE CABLE
Fig. 104 Cable At Tension Strut
1 ± TENSION STRUT MOUNTING BOLTS
2 ± TENSION STRUT
3 ± SPOOL BUSHING
4 ± NUT
5 ± PARKING BRAKE CABLE
5 - 52 BRAKESPL
REMOVAL AND INSTALLATION (Continued)

CALIPER PISTON AND SEALS
CALIPER PISTON REMOVAL
WARNING: UNDER NO CONDITION SHOULD HIGH
PRESSURE AIR EVER BE USED TO REMOVE A PIS-
TON FROM A CALIPER BORE. PERSONAL INJURY
COULD RESULT FROM SUCH A PRACTICE.
NOTE: The safest way to remove the piston from
the caliper bore is to use the hydraulic pressure of
the vehicle's brake system.
(1) Following the removal procedure in DISC
BRAKE SHOES found in this section, remove the
caliper from the brake rotor and hang the assembly
on a wire hook away from rotor and body of the vehi-
cle so brake fluid cannot get on these components.
Remove the brake shoes, and place a small piece of
wood between the piston and caliper fingers.
(2) Carefully depress the brake pedal to hydrauli-
cally push piston out of its bore. Once completed,
apply and hold down the brake pedal to any position
beyond the first inch of pedal travel using a brake
pedal holding tool. This will prevent the fluid in the
master cylinder reservoir from completely draining
out.(3) Disconnect the brake fluid flex hose from the
caliper assembly and remove it from the vehicle.
CALIPER SEAL REMOVAL
CAUTION: Do not use excessive force when clamp-
ing caliper in vise. Excessive vise pressure will
cause bore distortion.
(1) To disassemble the caliper, mount it in a vise
equipped with protective jaws.
(2) Remove the piston dust boot from the caliper
and discard (Fig. 118).
NOTE: Do not use a screw driver or other metal
tool for seal removal. Using such tools can scratch
the bore or leave burrs on the seal groove edges.
(3) Using a soft tool such as a plastic trim stick,
work the piston seal out of its groove in caliper pis-
ton bore (Fig. 119). Discard the old seal.
(4) Clean the piston bore and drilled passage ways
using alcohol or a suitable solvent. Wipe it dry using
only a lint-free cloth.
(5) Inspect the piston bore for scoring or pitting.
Bores that show light scratches or corrosion can usu-
ally be cleared of the light scratches or corrosion
using crocus cloth. Bores that have deep scratches or
scoring should be honed. Use Caliper Hone, Special
Tool C-4095, or the equivalent to hone the bore. Do
Fig. 117 Correctly Installed Guide Pin Sleeve And
Bushing
1 ± CALIPER
2 ± BUSHING
3 ± SLEEVE
Fig. 118 Removing Caliper/Piston Dust Boot
1 ± CALIPER
2 ± SCREWDRIVER
3 ± BOOT
PLBRAKES 5 - 57
DISASSEMBLY AND ASSEMBLY (Continued)

SPECIFICATIONS
BRAKE FLUID
The brake fluid used in this vehicle must conform
to DOT 3 specifications and SAE J1703 standards.
No other type of brake fluid is recommended or
approved for usage in the vehicle brake system. Use
only Mopar brake fluid or an equivalent from a
tightly sealed container.
CAUTION: Never use reclaimed brake fluid or fluid
from an container which has been left open. An
open container will absorb moisture from the air
and contaminate the fluid.
CAUTION: Never use any type of a petroleum-
based fluid in the brake hydraulic system. Use of
such type fluids will result in seal damage of the
vehicle brake hydraulic system causing a failure of
the vehicle brake system. Petroleum based fluids
would be items such as engine oil, transmission
fluid, power steering fluid, etc.
BRAKE ACTUATION SYSTEM
ACTUATION:
Vacuum Operated Power Brakes.....Standard
Hydraulic System.......Dual-Diagonally Split
BRAKE PEDAL:
Pedal Ratio..........................3.41
POWER BRAKE BOOSTER:
Make/Type..................Bosch/Vacuum
Mounting Studs.................. M8x1.25
Diaphragm Size/Type........ 205mmTandem
MASTER CYLINDER ASSEMBLY:
Type ........................Dual Tandem
Body Material...........Anodized Aluminum
Reservoir Material.............Polypropelene
MASTER CYLINDER BORE STROKE AND
SPLIT:
NonABS ..............22.23 mm x 34.0 mm
(0.875 in. x 1.34 in.)
ABS . . 23.82 mm x 34.0 mm (0.937 in. x 1.34 in.)
Displacement Split.................. 50/50MASTER CYLINDER FLUID OUTLET PORTS:
Tube Fitting Type...... SAE45ÉInverted Flare
W/ABS - Primary Tube Nut
Thread........................7/16 in.±24
W/ABS - Secondary Tube Nut
Thread........................ 3/8in.±24
W/O ABS - All Tube Nut Threads....7/16 in.±24
ABS HYDRAULIC CONTROL UNIT:
Hydraulic Tube Fitting
Type................ SAE45ÉInverted Flare
All Tube Nut Threads............7/16 in.±24
PROPORTIONING VALVE:
Material.......................Aluminum
Function.....Hydraulic Pressure Proportioning
BRAKE FASTENER TORQUE SPECIFICATIONS
DESCRIPTION TORQUE
BRAKE TUBES:
Tube Nuts............... 17N´m(145 in. lbs.)
MASTER CYLINDER:
Mounting Nuts.......... 28N´m(250 in. lbs.)
POWER BRAKE BOOSTER:
Mounting Nuts.......... 34N´m(300 in. lbs.)
DISC BRAKE CALIPER:
Caliper Banjo Bolt......... 48N´m(35ft.lbs.)
Guide Pin Bolts.......... 22N´m(192 in. lbs.)
Bleeder Screw........... 15N´m(125 in. lbs.)
WHEEL CYLINDER (REAR):
Mounting Bolts.......... 13N´m(115in.lbs.)
Bleeder Screw............ 10N´m(80in.lbs.)
DRUM BRAKE SHOE SUPPORT PLATE
(REAR):
Mounting Bolts........... 75N´m(55ft.lbs.)
DISC BRAKE ADAPTER (REAR):
Mounting Bolts........... 75N´m(55ft.lbs.)
HUB AND BEARING (REAR):
Retaining Nut.......... 217N´m(160 ft. lbs.)
PARKING BRAKE:
Lever Mounting Nuts..... 28N´m(250 in. lbs.)
TIRE AND WHEEL:
Wheel Mounting Nut...........109±150 N´m
(80±110 ft. lbs.)
INTEGRATED CONTROL UNIT:
Mounting Bolts........... 11N´m(97in.lbs.)
CAB Mounting bolts........ 2N´m(17in.lbs.)
Bracket-to-Frame Rail Bolts.......... 23N´m
(200 in. lbs.)
WHEEL SPEED SENSOR:
Head Mounting bolt...... 12N´m(105 in. lbs.)
PLBRAKES 5 - 63

ANTILOCK BRAKE SYSTEM
TABLE OF CONTENTS
page page
DESCRIPTION AND OPERATION
ANTILOCK BRAKE SYSTEM OPERATION......65
ANTILOCK BRAKE SYSTEM COMPONENTS....66
ELECTRONIC BRAKE DISTRIBUTION.........69
TRACTION CONTROL SYSTEM..............70
HYDRAULIC CIRCUITS AND VALVE
OPERATION...........................71
DIAGNOSIS AND TESTING
SERVICE WARNINGS AND CAUTIONS........74
ABS GENERAL DIAGNOSTICS INFORMATION . . 74
ABS WIRING DIAGRAM INFORMATION........74
ABS VEHICLE TEST DRIVE.................74
ABS ELECTRONIC DIAGNOSIS..............75
TONE WHEEL...........................76
BRAKE FLUID CONTAMINATION.............76
SERVICE PROCEDURES
BRAKE FLUID LEVEL CHECKING............77ANTILOCK BRAKE SYSTEM BLEEDING.......77
MASTER CYLINDER BLEEDING.............77
REMOVAL AND INSTALLATION
SERVICE WARNINGS AND CAUTIONS........78
MASTER CYLINDER......................78
INTEGRATED CONTROL UNIT...............79
WHEEL SPEED SENSOR (FRONT)...........81
WHEEL SPEED SENSOR (REAR)............83
DISASSEMBLY AND ASSEMBLY
INTEGRATED CONTROL UNIT...............84
SPECIFICATIONS
TONE WHEEL RUNOUT....................85
WHEEL SPEED SENSOR-TO-TONE WHEEL
CLEARANCE...........................85
BRAKE FASTENER TORQUE
SPECIFICATIONS.......................85
DESCRIPTION AND OPERATION
ANTILOCK BRAKE SYSTEM OPERATION
This section covers the physical and operational
descriptions, and the on-car service procedures for
the Mark 20e Antilock Brake System (ABS) with
traction control. It is the only antilock brake system
available on this vehicle.
The purpose of the antilock brake system is to pre-
vent wheel lockup under braking conditions on virtu-
ally any type of road surface. Antilock braking is
desirable because a vehicle that is stopped without
locking the wheels retains directional stability and
some steering capability. This allows the driver to
retain greater control of the vehicle during braking.
The traction control system reduces wheel slip and
maintains traction at the driving speeds below 56
kph (35 mph) when road conditions call for traction
assistance. Refer to TRACTION CONTROL SYSTEM
in this section for more information.
Vehicles equipped with ABS use electronic brake
distribution (EBD) to balance front-to-rear braking
when the brakes are applied in the partial braking
range. Refer to ELECTRONIC BRAKE DISTRIBU-
TION in this section for more information.
There are a few performance characteristics of the
Mark 20e Antilock Brake System that may at first
seem abnormal, but in fact are normal. These char-
acteristics are described below.
NORMAL BRAKING
Under normal braking conditions, the ABS func-
tions the same as a standard base brake system with
a diagonally split master cylinder and conventional
vacuum assist.
ABS BRAKING
ABS operation is available at all vehicle speeds
above 3±5 mph. If a wheel locking tendency is
detected during a brake application, the brake sys-
tem enters the ABS mode. During ABS braking,
hydraulic pressure in the four wheel circuits is mod-
ulated to prevent any wheel from locking. Each
wheel circuit is designed with a set of electric sole-
noids to allow modulation, although for vehicle sta-
bility, both rear wheel solenoids receive the same
electrical signal. Wheel lockup may be perceived at
the very end of an ABS stop and is considered nor-
mal.
During an ABS stop, the brakes hydraulic system
is still diagonally split. However, the brake system
pressure is further split into four control channels.
During antilock operation of the vehicle's brake sys-
tem, the wheels are controlled independently and are
on separate control channels.
The system can build, hold and release pressure at
each wheel, depending on signals generated by the
wheel speed sensors (WSS) at each wheel and
received at the controller antilock brake (CAB).
PLBRAKES 5 - 65

NOISE AND BRAKE PEDAL FEEL
During ABS braking, some brake pedal movement
may be felt. In addition, ABS braking will create
ticking, popping, or groaning noises heard by the
driver. This is normal and is due to pressurized fluid
being transferred between the master cylinder and
the brakes. If ABS operation occurs during hard
braking, some pulsation may be felt in the vehicle
body due to fore-and-aft movement of the suspension
as brake pressures are modulated.
At the end of an ABS stop, ABS is turned off when
the vehicle is slowed to a speed of 3±4 mph. There
may be a slight brake pedal drop anytime that the
ABS is deactivated, such as at the end of the stop
when the vehicle speed is less than 3 mph or during
an ABS stop where ABS is no longer required. These
conditions exist when a vehicle is being stopped on a
road surface with patches of ice, loose gravel, or sand
on it. Also, stopping a vehicle on a bumpy road sur-
face activates ABS because of the wheel hop caused
by the bumps.
TIRE NOISE AND MARKS
Although the ABS system prevents complete wheel
lockup, some wheel slip is desired in order to achieve
optimum braking performance. Wheel slip is defined
as follows: 0 percent slip means the wheel is rolling
freely and 100 percent slip means the wheel is fully
locked. During brake pressure modulation, wheel slip
is allowed to reach up to 25±30 percent. This means
that the wheel rolling velocity is 25±30 percent less
than that of a free rolling wheel at a given vehicle
speed. This slip may result in some tire chirping,
depending on the road surface. This sound should not
be interpreted as total wheel lockup.
Complete wheel lockup normally leaves black tire
marks on dry pavement. The ABS will not leave dark
black tire marks since the wheel never reaches a
fully locked condition. However, tire marks may be
noticeable as light patched marks.
START-UP CYCLE
When the ignition is turned on, a popping sound
and a slight brake pedal movement may be noticed.
The ABS warning lamp will also be on for up to 5
seconds after the ignition is turned on. When the
vehicle is first driven off, a humming may be heard
or felt by the driver at approximately 20±40 kph
(12±25 mph). All of these conditions are a normal
function of ABS as the system is performing a diag-
nosis check.
PREMATURE ABS CYCLING
Symptoms of premature ABS cycling include: click-
ing sounds from the solenoid valves; pump/motor
running; and pulsations in the brake pedal. Prema-ture ABS cycling can occur at any braking rate of the
vehicle and on any type of road surface. Neither the
red BRAKE warning lamp, nor the amber ABS warn-
ing lamp, illuminate and no fault codes are stored in
the CAB.
Premature ABS cycling is a condition that needs to
be correctly assessed when diagnosing problems with
the antilock brake system. It may be necessary to use
a DRB scan tool to detect and verify premature ABS
cycling.
Check the following common causes when diagnos-
ing premature ABS cycling: damaged tone wheels;
incorrect tone wheels; damaged steering knuckle
wheel speed sensor mounting bosses; loose wheel
speed sensor mounting bolts; excessive tone wheel
runout; or an excessively large tone wheel-to-wheel
speed sensor air gap. Give special attention to these
components when diagnosing a vehicle exhibiting
premature ABS cycling.
After diagnosing the defective component, repair or
replace it as required. When the component repair or
replacement is completed, test drive the vehicle to
verify that premature ABS cycling has been cor-
rected.
ANTILOCK BRAKE SYSTEM COMPONENTS
The following is a detailed description of the
antilock brake system components. For information
on servicing base brake system components used in
conjunction with these components, see the BASE
BRAKE SYSTEM found at the beginning of this ser-
vice manual group.
MASTER CYLINDER
A vehicle equipped with ABS uses a different mas-
ter cylinder than a vehicle that is not equipped with
ABS. Vehicles equipped with ABS use a center port
master cylinder with only two outlet ports (Fig. 1).
The brake tubes from the primary and secondary
outlet ports on the master cylinder go directly to the
integrated control unit (ICU).
The master cylinder mounts to the power brake
booster in the same manner a non-ABS master cylin-
der does.
INTEGRATED CONTROL UNIT (ICU)
The hydraulic control unit (HCU) and the control-
ler antilock brake (CAB) used with this antilock
brake system are combined (integrated) into one
unit, which is called the integrated control unit (ICU)
(Fig. 2). The ICU is located on the driver's side of the
vehicle, and is mounted to the left front frame rail
below the master cylinder (Fig. 1).
5 - 66 BRAKESPL
DESCRIPTION AND OPERATION (Continued)

The ABS with traction control ICU consists of the
following components: the CAB, eight (build/decay)
solenoid valves (four inlet valves and four outlet
valves), two hydraulic shuttle valves, two traction
control valves, valve block, fluid accumulators, a
pump, and an electric pump/motor.
The replaceable components of the ICU are the
HCU and the CAB. No attempt should be made to
service any components found inside of the HCU or
CAB.
CONTROLLER ANTILOCK BRAKE (CAB)
The controller antilock brake (CAB) is a micropro-
cessor-based device which monitors the ABS system
during normal braking and controls it when the vehi-
cle is in an ABS stop. The CAB is mounted to the
bottom of the HCU (Fig. 2). The CAB uses a 25-way
electrical connector on the vehicle wiring harness.
The power source for the CAB is through the ignition
switch in the RUN or ON position. The CAB is on
the PCI bus.
The primary functions of the (CAB) are to:
(1) monitor the antilock brake system for proper
operation.
(2) detect wheel locking or wheel slipping tenden-
cies by monitoring the speed of all four wheels of the
vehicle.
(3) control fluid modulation to the wheel brakes
while the system is in an ABS mode or the traction
control system is activated.
(4) store diagnostic information.
(5) provide communication to the DRB scan tool
while in diagnostic mode.
The CAB constantly monitors the antilock brake
system for proper operation. If the CAB detects a
fault, it will send a message to the mechanical instu-
ment cluster (MIC) instructing it to turn on the
amber ABS warning lamp and disable the antilock
braking system. The normal base braking system will
remain operational.
The CAB continuously monitors the speed of each
wheel through the signals generated by the wheel
speed sensors to determine if any wheel is beginning
to lock. When a wheel locking tendency is detected,
the CAB commands the CAB command coils to actu-
ate. The CAB command coils then open and close the
valves in the HCU that modulate brake fluid pres-
sure in some or all of the hydraulic circuits. The CAB
continues to control pressure in individual hydraulic
circuits until a locking tendency is no longer present.
The CAB contains a self-diagnostic program that
monitors the antilock brake system for system faults.
When a fault is detected, the amber ABS warning
lamp is turned on and the fault diagnostic trouble
code (DTC) is then stored in a diagnostic program
memory. These DTC's will remain in the CAB mem-
ory even after the ignition has been turned off. The
DTC's can be read and cleared from the CAB mem-
ory by a technician using the DRB scan tool. If not
cleared with a DRB scan tool, the fault occurrence
and DTC will be automatically cleared from the CAB
memory after the identical fault has not been seen
during the next 3,500 miles of vehicle operation.
Fig. 1 Master Cylinder And ICU
1 ± PRIMARY BRAKE TUBE
2 ± MASTER CYLINDER
3 ± SECONDARY BRAKE TUBE
4 ± ABS ICU
Fig. 2 Integrated Control Unit (ICU)
1 ± HCU
2 ± PUMP/MOTOR
3 ± CAB
PLBRAKES 5 - 67
DESCRIPTION AND OPERATION (Continued)