air DODGE NEON 2000 Service Owner's Manual

(4) Fill the reservoir with fresh clean DOT 3 brake
fluid. Refer to BRAKE FLUID LEVEL CHECKING
in the SERVICE PROCEDURES section in this sec-
tion of this service manual group.
BRAKE FLUID LEVEL SWITCH
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
REMOVAL
(1) Remove the vehicle wiring harness connector
from brake fluid level switch in master cylinder
brake fluid reservoir (Fig. 44).
(2) Push together the retaining tabs holding the
brake fluid level switch in place in the brake fluid
reservoir (Fig. 46).
(3) Pull the brake fluid level switch out the other
side of the reservoir.
INSTALLATION
(1) Align the brake fluid level switch with its
mounting hole on the left side of the master cylinder
brake fluid reservoir. Push the switch into the fluid
reservoir until the switch retaining tabs are
expanded on the other side of the reservoir, locking it
in place (Fig. 46).
(2) Connect the brake fluid level switch wiring
connector (Fig. 44).
POWER BRAKE BOOSTER
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
REMOVAL
(1) Disconnect negative (ground) cable from the
battery and isolate the cable.
(2) Disconnect the positive cable from the battery,
then remove the battery from the battery tray. There
is one nut securing the clamp on the backside of the
battery holding it in place.
(3) Remove the one nut and one bolt securing the
air cleaner box in place, then disconnect the wiring
harness connector at the air inlet sensor.
(4) Lift the air cleaner box upward enough to clear
its grommeted alignment post (Fig. 48), then move
the air cleaner box forward just enough to access the
battery tray mounting bolts.(5) Remove the 2 bolts, then the 2 nuts mounting
the battery tray to its bracket (Fig. 48). Remove the
battery tray.
CAUTION: The vacuum in the power brake booster
must be pumped down before removing the master
cylinder to prevent the booster from sucking in any
contamination. This can be done by pumping the
brake pedal 4-5 times while the engine is not run-
ning until a firm brake pedal is achieved.
(6) Remove the master cylinder. For the master
cylinder without ABS removal and installation proce-
dure, refer to MASTER CYLINDER in this section of
this service manual group. For the master cylinder
with ABS removal and installation procedure, refer
to MASTER CYLINDER in the ANTILOCK BRAKE
SYSTEM section of this service manual group.
(7) If the vehicle is equipped with ABS, remove the
integrated control unit (ICU). Refer to INTEGRATED
CONTROL UNIT in REMOVAL AND INSTALLA-
TION within the ANTILOCK BRAKE SYSTEM sec-
tion of this service manual group for the procedure.
(8) If the vehicle is equipped with ABS, remove the
three bolts securing the ICU mounting bracket to the
frame rail.
(9) Disconnect the vacuum hoses from the check
valve on the power brake booster (Fig. 49), but do not
remove the check valve from power brake booster.
(10) Locate the brake pedal-to-power brake booster
input rod attachment under the instrument panel.
Position a small screwdriver (Fig. 50) under the cen-
ter tang of the retaining clip. Rotate the screwdriver
enough to allow the retaining clip tang to pass over
the end of the brake pedal pin. Remove the clip.
Fig. 48 Battery Tray Mounting
1 ± BATTERY TRAY MOUNTING NUTS
2 ± BATTERY TRAY MOUNTING BOLTS
3 ± AIR CLEANER BOX POST
5 - 30 BRAKESPL
REMOVAL AND INSTALLATION (Continued)

CAUTION: Use only a new brake booster input rod-
to-brake pedal retaining clip to ensure proper
retainment.
(4) Connect the power brake booster input rod-to-
brake pedal pin. Install a new retaining clip. Do not
use the old clip.
(5) Connect all previously removed vacuum hoses
to the vacuum check valve (Fig. 49).
(6) If the vehicle is equipped with ABS, install the
ICU mounting bracket on the frame rail using its
three bolts. Tighten the nuts to a torque of 23 N´m
(200 in. lbs.).
(7) If the vehicle is equipped with ABS, reinstall
the ICU. Refer to INTEGRATED CONTROL UNIT in
REMOVAL AND INSTALLATION within the
ANTILOCK BRAKE SYSTEM section of this service
manual group for the procedure.
(8) Install the master cylinder. For the master cyl-
inder without ABS removal and installation proce-
dure, refer to MASTER CYLINDER in this section of
this service manual group. For the master cylinder
with ABS removal and installation procedure, refer
to MASTER CYLINDER in the ANTILOCK BRAKE
SYSTEM section of this service manual group.
(9) Position the battery tray back in place. Install
the two bolts, then the two nuts mounting the bat-
tery tray to its bracket (Fig. 48). Tighten the two
bolts and nuts to a torque of 34 N´m (25 ft. lbs.).
(10) Reinstall the air cleaner box onto its grom-
meted alignment post (Fig. 48).
(11) Install the one nut and one bolt securing the
air cleaner box in place, then connect the wiring har-
ness connector at the air inlet sensor.
(12) Install the battery and clamp it in place.
(13) Connect the positive, then the negative
(ground) cable on the battery.
(14) Adjust the stop lamp switch as necessary.
Refer to STOP LAMP SWITCH in the ADJUST-
MENTS section of this group.
(15) Bleed the base brake system.
(16) Road test the vehicle to ensure proper opera-
tion of the brakes.
PROPORTIONING VALVE
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
REMOVAL
(1) Using a brake pedal holder, depress the brake
pedal past its first one inch of travel and hold it in
this position (Fig. 53). This will isolate the master
cylinder from the brake hydraulic system and willnot allow the brake fluid to drain out of the master
cylinder reservoir.
(2) Disconnect the brake tube from the proportion-
ing valve requiring removal (Fig. 54).
(3) Unscrew the Proportioning valve from the mas-
ter cylinder.
Fig. 53 Brake Pedal Holder
1 ± CLUTCH PEDAL (IF EQUIPPED WITH MANUAL TRANSAXLE)
2 ± THROTTLE PEDAL
3 ± BRAKE PEDAL HOLDING TOOL
4 ± STEERING WHEEL
5 ± DRIVER'S SEAT
6 ± BRAKE PEDAL
Fig. 54 Proportioning Valves On Master Cylinder
1 ± RIGHT FRONT BRAKE TUBE
2 ± LEFT FRONT BRAKE TUBE
3 ± LEFT REAR BRAKE TUBE
4 ± REAR PROPORTIONING VALVES
5 ± RIGHT REAR BRAKE TUBE
5 - 32 BRAKESPL
REMOVAL AND INSTALLATION (Continued)

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)

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

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)

AMBER ABS WARNING LAMP
The amber ABS warning lamp is located in the
instrument cluster. The purpose of the warning lamp
is discussed in detail below.
When the ignition key is turned to the ON posi-
tion, the amber ABS warning lamp is lit until the
CAB completes its self-tests and turns off the lamp
(approximately 4 seconds). The amber ABS warning
lamp will illuminate when the CAB detects a condi-
tion that results in the shutdown of ABS function.
The CAB sends a message to the mechanical instu-
ment cluster (MIC) instructing it to turn on the
amber ABS warning lamp.
Under most conditions, when the amber ABS warn-
ing lamp is on, only the ABS function of the brake
system is affected; The electronic brake distribution
(EBD), the base brake system and the ability to stop
the vehicle are not affected.
WHEEL SPEED SENSOR (WSS)
At each wheel of the vehicle there is one wheel
speed sensor (WSS) and one tone wheel (Fig. 3) (Fig.
4) (Fig. 5) (Fig. 6). Each front wheel speed sensor is
attached to a boss in the steering knuckle. The front
tone wheel is part of the driveshaft outboard con-
stant velocity joint. The rear wheel speed sensor is
mounted to the rear disc brake adapter. The rear
tone wheel is an integral part of the rear wheel hub
and bearing.
The wheel speed sensor operates on electronic
energy supplied by the CAB and outputs a square
wave signal whose current alternates between two
constant levels. Its frequency is proportional to the
speed of the tone wheel. The output is available as
long as the sensor is powered and its state (high or
low) corresponds to the presence or absence of tone
wheel teeth. The output signal is sent to the CAB. If
a wheel locking tendency is detected by the CAB, it
will then modulate hydraulic pressure via the HCU
to prevent the wheel(s) from locking.
Correct ABS operation is dependent on accurate
wheel speed signals. The vehicle's tires and wheels
all must be the same size and type to generate accu-
rate signals. Variations in tire and wheel size can
produce inaccurate wheel speed signals.
Improper speed sensor-to-tone wheel clearance can
cause erratic speed sensor signals. The speed sensor
air gap is not adjustable, but should be checked when
applicable. Wheel speed sensor-to-tone wheel clear-
ance specifications can be found in the SPECIFICA-
TIONS section within this section in this service
manual group.
ELECTRONIC BRAKE DISTRIBUTION
Vehicles equipped with ABS use electronic brake
distribution (EBD) to balance front-to-rear braking.The EBD is used in place of a rear proportioning
valve. The EBD system uses the ABS system to con-
trol the slip of the rear wheels in partial braking
range. The braking force of the rear wheels is con-
trolled electronically by using the inlet and outlet
valves located in the integrated control unit.
Upon entry into EBD the inlet valve for the rear
brake circuit is switched on so that the fluid supply
from the master cylinder is shut off. In order to
decrease the rear brake pressure, the outlet valve for
Fig. 3 Left Front Wheel Speed Sensor
1 ± LEFT FRONT WHEEL SPEED SENSOR
2 ± TONE WHEEL
Fig. 4 Right Front Wheel Speed Sensor
1 ± RIGHT FRONT WHEEL SPEED SENSOR
2 ± TONE WHEEL
PLBRAKES 5 - 69
DESCRIPTION AND OPERATION (Continued)

ABS ELECTRONIC DIAGNOSIS
The following information is presented to give the
technician a general background on the diagnostic
capabilities of the ABS system. Complete electronic
diagnosis of the ABS system used on this vehicle is
covered in the Chassis Diagnostic Procedures manual.
Electronic diagnosis of the ABS system used on
this vehicle is performed using the DRBIIItscan
tool. The vehicle's scan tool diagnostic connector is
located under the steering column lower cover, to the
left side of the steering column (Fig. 10).
ABS SELF-DIAGNOSIS
The ABS system is equipped with a self-diagnosis
capability, which may be used to assist in the isola-
tion of ABS faults. The features are described below.
START-UP CYCLE
The self-diagnosis ABS start-up cycle begins when
the ignition switch is turned to the ON position.
Electrical checks are completed on ABS components,
including the CAB, solenoid continuity, and the relay
system operation. During this check the amber ABS
warning lamp is turned on for approximately 5 sec-
onds and the brake pedal may emit a popping sound,
moving slightly when the solenoid valves are
checked.
DRIVE-OFF CYCLE
The first time the vehicle is set in motion after an
ignition off/on cycle, the drive-off cycle occurs. This
cycle is performed when the vehicle reaches a speed
of approximately 20 kph (12 mph.).²The pump/motor is briefly activated to verify
function. When the pump/motor is briefly activated, a
whirling or buzzing sound may be heard by the
driver. This sound is normal, indicating the pump/
motor is running.
²The wheel speed sensor output correct operating
range is verified.
ONGOING TESTS
While the system is operating, these tests are per-
formed on a continuous basis:
²solenoid continuity
²wheel speed sensor continuity
²wheel speed sensor output
DIAGNOSTIC TROUBLE CODES (DTC's)
Diagnostic trouble codes (DTC's) are kept in the
controller's memory until either erased by the techni-
cian using the DRB, or erased automatically after
3500 miles or 255 ignition key cycles, whichever
occurs first. DTC's are retained by the controller
even if the ignition is turned off or the battery is dis-
connected. More than one DTC can be stored at a
time. When accessed, the number of occurrences
(ignition key cycles) and the DTC that is stored are
displayed. Most functions of the CAB and the ABS
system can be accessed by the technician for testing
and diagnostic purposes using the DRB.
LATCHING VERSUS NON-LATCHING DIAGNOSTIC TROUBLE
CODES
Some DTC's detected by the CAB are ªlatchingº
codes. The DTC is latched and ABS braking is dis-
abled until the ignition switch is reset. Thus, ABS
braking is non-operational even if the original DTC
has disappeared. Other DTC's are non-latching. Any
warning lamps that are turned on are only turned on
as long as the DTC condition exists; as soon as the
condition goes away, the amber ABS warning lamp is
turned off, although, in most cases, a DTC is set.
INTERMITTENT DIAGNOSTIC TROUBLE CODES
As with virtually any electronic system, intermit-
tent electrical problems in the ABS system may be
difficult to accurately diagnose. Most intermittent
electrical problems are caused by faulty electrical
connections or wiring. A visual inspection should be
done before trying to diagnose or service the antilock
brake system; this will eliminate unnecessary diag-
nosis and testing time. Perform a visual inspection
for loose, disconnected, damaged, or misrouted wires
or connectors; include the following components and
areas of the vehicle in the inspection.
(1) Inspect fuses in the power distribution center
(PDC) and the wiring junction block. Verify that all
fuses are fully inserted into the PDC and wiring
Fig. 10 ABS System Diagnostic Connector Location
1 ± DRIVER AIRBAG MODULE
2 ± PASSENGER AIRBAG MODULE
3 ± DATA LINK CONNECTOR
PLBRAKES 5 - 75
DIAGNOSIS AND TESTING (Continued)

SERVICE PROCEDURES
BRAKE FLUID LEVEL CHECKING
CAUTION: Use only Mopar brake fluid or an equiv-
alent from a tightly sealed container. Brake fluid
must conform to DOT 3 specifications. Do not use
petroleum-based fluid because seal damage in the
brake system will result.
Refer to SERVICE PROCEDURES in the BASE
BRAKE SYSTEM section in this group for the proper
procedure to check and adjust the brake fluid level in
the master cylinder fluid reservoir.
ANTILOCK BRAKE SYSTEM BLEEDING
The base brake's hydraulic system must be bled
anytime air enters the hydraulic system. The ABS
though, particularly the ICU (HCU), should only be
bled when the HCU is replaced or removed from the
vehicle. The ABS must always be bled anytime it is
suspected that the HCU has ingested air. Under
most circumstances that require the bleeding of the
brakes hydraulic system, only the base brake
hydraulic system needs to be bled.
It is important to note that excessive air in the
brake system will cause a soft or spongy feeling
brake pedal.
During the brake bleeding procedure, be sure the
brake fluid level remains close to the FULL level in
the master cylinder fluid reservoir. Check the fluid
level periodically during the bleeding procedure and
add DOT 3 brake fluid as required.
The ABS must be bled as two independent braking
systems. The non-ABS portion of the brake system
with ABS is to be bled the same as any non-ABS sys-
tem.
The ABS portion of the brake system must be bled
separately. Use the following procedure to properly
bleed the brake hydraulic system including the ABS.
BLEEDING
When bleeding the ABS system, the following
bleeding sequence must be followed to insure com-
plete and adequate bleeding.
(1) Make sure all hydraulic fluid lines are installed
and properly torqued.
(2) Connect the DRB scan tool to the diagnostics
connector. The diagnostic connector is located under
the lower steering column cover to the left of the
steering column.
(3) Using the DRB, check to make sure the CAB
does not have any fault codes stored. If it does, clear
them using the DRB.WARNING: WHEN BLEEDING THE BRAKE SYSTEM
WEAR SAFETY GLASSES. A CLEAR BLEED TUBE
MUST BE ATTACHED TO THE BLEEDER SCREWS
AND SUBMERGED IN A CLEAR CONTAINER FILLED
PART WAY WITH CLEAN BRAKE FLUID. DIRECT
THE FLOW OF BRAKE FLUID AWAY FROM YOUR-
SELF AND THE PAINTED SURFACES OF THE VEHI-
CLE. BRAKE FLUID AT HIGH PRESSURE MAY
COME OUT OF THE BLEEDER SCREWS WHEN
OPENED.
(4) Bleed the base brake system using the stan-
dard pressure or manual bleeding procedure as out-
lined in SERVICE PROCEDURES in the BASE
BRAKE SYSTEM section at the beginning of this
group.
(5) Using the DRB, select ANTILOCK BRAKES,
followed by MISCELLANEOUS, then BLEED
BRAKES. Follow the instructions displayed. When
the scan tool displays TEST COMPLETED, discon-
nect the scan tool and proceed.
(6) Bleed the base brake system a second time.
Check brake fluid level in the reservoir periodically
to prevent emptying, causing air to enter the hydrau-
lic system.
(7) Fill the master cylinder reservoir to the full
level.
(8) Test drive the vehicle to be sure the brakes are
operating correctly and that the brake pedal does not
feel spongy.
MASTER CYLINDER BLEEDING
(1) Clamp the master cylinder in a vise.
(2) Attach Master Cylinder Bleed Tube, Special
Tool 8358-1, to the primary port of the master cylin-
der and tighten in place (Fig. 11). Attach Master Cyl-
inder Bleed Tube, Special Tool 8358-2, to the
secondary port of the master cylinder and tighten in
place. Position the other end of the tubes into the
master cylinder reservoir so their outlets are below
the surface of the brake fluid in the reservoir when
filled.
(3) Fill the brake fluid reservoir with Mopart
brake fluid, or an equivalent conforming to DOT 3
specifications.
(4) Using a wooden dowel as a pushrod (Fig. 11),
press the pistons inward slowly applying brake pres-
sure, then release the pressure, allowing the pistons
to return to the released position. Repeat this several
times until all air bubbles are expelled out of the
tubes and master cylinder bore.
(5) Remove the bleed tubes from the master cylin-
der and plug the outlet ports.
(6) Install the fill cap on the reservoir.
(7) Remove the master cylinder from the vise.
PLBRAKES 5 - 77

NOTE: It is not necessary to bleed the entire
hydraulic system after replacing just the master cyl-
inder unless the brake system has been open to air
for an excessive amount of time or air is present in
the lines. Only the master cylinder must be bled
and filled.
REMOVAL AND INSTALLATION
SERVICE WARNINGS AND CAUTIONS
Review this entire section prior to performing any
mechanical work on a vehicle equipped with ABS.
This section contains information on precautions per-
taining to potential component damage, vehicle dam-
age and personal injury which could result when
servicing an ABS equipped vehicle.
CAUTION: Only the recommended jacking or hoist-
ing positions for this vehicle are to be used when-
ever it is necessary to lift a vehicle. Failure to raise
a vehicle from the recommended locations could
result in lifting a vehicle by the hydraulic control
unit mounting bracket. Lifting a vehicle by the
hydraulic control unit mounting bracket will result
in damage to the mounting bracket and the hydrau-
lic control unit.
CAUTION: An attempt to remove or disconnect cer-
tain system components may result in improper
system operation. Only those components with
approved removal and installation procedures in
this manual should be serviced.CAUTION: Brake fluid will damage painted sur-
faces. If brake fluid is spilled on any painted sur-
faces, wash off with water immediately.
CAUTION: When performing any service procedure
on a vehicle equipped with ABS do not apply a
12-volt power source to the ground circuit of the
pump motor in the HCU. Doing this will damage the
pump motor and will require replacement of the
entire HCU.
CAUTION: If welding work is to be performed on
the vehicle, using an electric arc welder, the CAB
connector should be disconnected during the weld-
ing operation.
CAUTION: The CAB 25-way connector should never
be connected or disconnected with the ignition
switch in the ON position.
Many components of the ABS System are not ser-
viceable and must be replaced as an assembly. Do not
disassemble any component which is not designed to
be serviced.
MASTER CYLINDER
NOTE: Before proceeding with this procedure,
review SERVICE WARNINGS AND CAUTIONS at the
beginning of REMOVAL AND INSTALLATION in this
section.
REMOVAL
CAUTION: The vacuum in the power brake booster
must be pumped down before removing the master
cylinder to prevent the booster from sucking in any
contamination. This can be done by pumping the
brake pedal while the engine is not running until a
firm brake pedal is achieved.
(1) With the engine not running, pump the brake
pedal 4-5 strokes until the pedal feel is firm.
(2) Disconnect the negative (ground) cable from
the battery and isolate the cable.
(3) Disconnect the positive cable from the battery,
then remove the battery from the battery tray. There
is one nut securing the clamp on the backside of the
battery holding it in place.
(4) Disconnect the wiring harness connector from
the brake fluid level switch on the master cylinder
reservoir (Fig. 12).
Fig. 11 Bleeding Master Cylinder
1 ± WOODEN DOWEL
2 ± MASTER CYLINDER
5 - 78 BRAKESPL
SERVICE PROCEDURES (Continued)