Page 201 of 2339

CAUTION
The ABS uses an electronic control module, the
CAB. This module is designed to withstand normal
current draws associated with vehicle operation.
Care must be taken to avoid overloading the CAB
circuits.
CAUTION: In testing for open or short circuits, do
not ground or apply voltage to any of the circuits
unless instructed to do so for a diagnostic proce-
dure.
CAUTION: These circuits should only be tested
using a high impedance multi-meter or the DRBIIIT
scan tool as described in this section. Power
should never be removed or applied to any control
module with the ignition in the ON position. Before
removing or connecting battery cables, fuses, or
connectors, always turn the ignition to the OFF
position.
CAUTION: The CAB 24-way connector should never
be connected or disconnected with the ignition
switch in the ON position.
CAUTION: This vehicle utilizes active wheel speed
sensors. Do not apply voltage to wheel speed sen-
sors at any time.
CAUTION: Use only factory wiring harnesses. Do
not cut or splice wiring to the brake circuits. The
addition of aftermarket electrical equipment (car
phone, radar detector, citizen band radio, trailer
lighting, trailer brakes, etc.) on a vehicle equipped
with antilock brakes may affect the function of the
antilock brake system.
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: 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: If welding work is to be performed on the
vehicle using an electric arc welder, the CAB con-nector should be disconnected during the welding
operation.
CAUTION: Many components of the ABS System
are not serviceable and must be replaced as an
assembly. Do not disassemble any component
which is not designed to be serviced.
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: Brake fluid will damage painted surfaces.
If brake fluid is spilled on any painted surface,
wash off with water immediately.
STANDARD PROCEDURE - 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.
5 - 90 BRAKES - ABSRS
BRAKES - ABS (Continued)
Page 202 of 2339

(1) Make sure all hydraulic fluid lines are installed
and properly torqued.
(2) Connect the DRBIIItscan tool to the diagnos-
tics 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. (Refer
to 5 - BRAKES - BASE - STANDARD PROCEDURE)
(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.
SPECIFICATIONS
ABS FASTENER TORQUE
Refer to BRAKE FASTENER TORQUE. (Refer to 5
- BRAKES - BASE - SPECIFICATIONS)
TONE WHEEL RUNOUT
DESCRIPTION SPECIFICATION
Front Tone Wheel
Maximum Runout0.15 mm (0.006 in.)
Rear Tone Wheel
Maximum Runout0.15 mm (0.006 in.)
WHEEL SPEED SENSOR AIR GAP
DESCRIPTION SPECIFICATION
Front Sensor0.35 ± 1.20 mm
0.014 ± 0.047 in.
Rear Sensor0.40 ± 1.20 mm
0.016 ± 0.047 in.
FRONT WHEEL SPEED
SENSOR
REMOVAL
(1)Raise vehicle. (Refer to LUBRICATION & MAIN-
TENANCE/HOISTING - STANDARD PROCEDURE)
(2) Remove the tire and wheel assembly.
(3) Remove the sensor cable routing clamp screws.
CAUTION: When disconnecting the wheel speed
sensor from vehicle wiring harness, be careful not
to damage pins on connector
(4) Remove speed sensor cable grommets from
intermediate bracket on strut.
(5) Disconnect speed sensor cable from vehicle wir-
ing harness behind fender well shield.
(6) Remove the wheel speed sensor head mounting
bolt (Fig. 1).
(7) Remove sensor head from steering knuckle. If
sensor has seized due to corrosion,DO NOT USE
PLIERS ON SENSOR HEAD.Use a hammer and a
punch and tap edge of sensor ear, rocking the sensor
side-to-side until free.
Fig. 1 Front Wheel Speed Sensor Attaching Bolt
1 - MOUNTING BOLT
2 - WHEEL SPEED SENSOR
3 - DRIVESHAFT
4 - TONE WHEEL
5 - STEERING KNUCKLE
RSBRAKES - ABS5-91
BRAKES - ABS (Continued)
Page 203 of 2339

(8) Remove front wheel speed sensor from vehicle.
INSTALLATION
CAUTION: Proper installation of wheel speed sen-
sor cables is critical to continued system operation.
Be sure that cables are installed in retainers. Fail-
ure to install cables in retainers as shown in this
section may result in contact with moving parts and
over extension of cables, resulting in an open cir-
cuit.
(1) Connect the front wheel speed sensor cable to
the vehicle wiring harness connector. Be sure speed
sensor cable connector is fully seated and locked into
vehicle wiring harness connector.
(2) Install the bolts attaching the routing clamps
to the body of the vehicle. Tighten the bolts to a
torque of 14 N´m (125 in. lbs.).
(3) Insert speed sensor cable grommets into inter-
mediate bracket on strut.
(4) Install the wheel speed sensor head mounting
bolt (Fig. 1). Tighten the bolt to a torque of 13 N´m
(115 in. lbs.)
(5) Install the wheel and tire assembly on vehicle.
(6) Lower vehicle.
(7) Road test vehicle to ensure proper operation of
the base and ABS brake systems.
REAR WHEEL SPEED SENSOR
-AWD
REMOVAL
(1) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE)
CAUTION: When disconnecting speed sensor cable
from vehicle wiring harness be careful not to dam-
age pins on the electrical connectors. Also, inspect
connectors for any signs of previous damage.
(2) Remove grommet from floor pan of vehicle and
disconnect speed sensor cable connector from vehicle
wiring harness.
CAUTION: When removing rear wheel speed sensor
cable from routing clips, be sure not to damage the
routing clips. Routing clips that are molded onto
the brake hose will require replacement of the brake
hose if damaged during removal or installation of
the speed sensor cable.
(3) Carefully remove speed sensor cable from
press-in routing clips along brake hose and tubing.(4) Remove bolt securing wheel speed sensor cable
metal clip to rear of axle. Remove metal clip from
cable if necessary.
CAUTION: If speed sensor head has seized due to
corrosion, do not use pliers on speed sensor head
in an attempt to remove it. Use a hammer and a
punch and tap mounting flange edge side-to-side,
rocking the sensor until free.
(5) Remove wheel speed sensor head attaching
bolt.
(6) Remove wheel speed sensor head from the axle,
and remove sensor from vehicle.
INSTALLATION
CAUTION: Proper installation of wheel speed sen-
sor cables is critical to continued system operation.
Be sure that cables are installed in retainers. Fail-
ure to install cables in retainers as indicated may
result in contact with moving parts or over-exten-
sion of cables, resulting in an open circuit.
(1) Install wheel speed sensor head in axle flange.
CAUTION: Prior to installing the speed sensor head
attaching bolt, the plastic anti-rotation pin must be
fully seated into the bearing flange.
(2) Install wheel speed sensor head attaching bolt.
Tighten bolt to a torque 10 N´m (90 in. lbs.).
(3) Check the air gap between the face of the
wheel speed sensor and the top surface of the tone
wheel. (Refer to 5 - BRAKES - SPECIFICATIONS)
CAUTION: When installing wheel speed sensor
cable in the routing clips on rear brake flex hose,
be sure not to damage the routing clips. Routing
clips are molded onto the hose and will require
replacement of the brake hose if damaged.
(4) Install speed sensor cable under leaf spring
onto brake hose and tubing utilizing routing clips to
secure it in place.
(5) Install metal routing clip on speed sensor cable
and mount it to rear of axle with mounting bolt.
Tighten mounting bolt to 16 N´m (140 in. lbs.).
(6) Connect wheel speed sensor cable to vehicle
wiring harness.Be sure speed sensor cable con-
nector is fully seated and locked into vehicle
wiring harness connector.
(7) Install speed sensor cable grommet into the
floor pan, being sure the grommet is fully seated into
the access hole.
(8) Lower vehicle.
(9) Road test vehicle to ensure proper operation of
the base and ABS braking systems.
5 - 92 BRAKES - ABSRS
FRONT WHEEL SPEED SENSOR (Continued)
Page 204 of 2339

REAR WHEEL SPEED SENSOR
- FWD
REMOVAL
(1) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE)
CAUTION: When disconnecting speed sensor cable
from vehicle wiring harness be careful not to dam-
age pins on the electrical connectors. Also, inspect
connectors for any signs of previous damage.
(2) Remove grommet from floor pan of vehicle and
disconnect speed sensor cable connector from vehicle
wiring harness (Fig. 2).
CAUTION: When removing rear wheel speed sensor
cable from routing clips, be sure not to damage the
routing clips. Routing clips that are molded onto
the brake hose will require replacement of the brake
hose if damaged during removal or installation of
the speed sensor cable.
(3) Carefully remove speed sensor cable from
press-in routing clips (Fig. 3).
(4) Remove bolt securing metal routing clip to rear
of axle and remove sensor cable from metal clip (Fig.
3).
(5) Remove secondary (yellow) retaining clip at
rear of wheel speed sensor head (Fig. 4).
(6) Push up on metal retaining clip (Fig. 4) until it
bottoms. This will release wheel speed sensor head
from hub and bearing. While holding metal clip up,
pull back on wheel speed sensor head removing it
from hub and bearing.(7) Remove wheel speed sensor assembly from
vehicle.
INSTALLATION
CAUTION: Proper installation of wheel speed sen-
sor cable is critical to continued system operation.
Be sure that cable is installed in routing retainers/
clips. Failure to install cable in retainers may result
in contact with moving parts or over extension of
cable, resulting in an open circuit.
CAUTION: It is important that only MoparTWheel
Bearing Grease be used for the following step appli-
cation. Other lubricants may cause sensor failure.
Fig. 2 Wheel Speed Sensor Connector
1 - CONNECTOR
2 - FLOOR PAN
3 - GROMMET
Fig. 3 SPEED SENSOR CABLE ROUTING
1 - METAL CLIP AND MOUNTING BOLT
2 - ROUTING CLIPS
Fig. 4 SENSOR CONNECTION AT HUB AND
BEARING
1 - SECONDARY SENSOR RETAINING CLIP
2 - METAL SENSOR RETAINING CLIP
3 - HUB AND BEARING
RSBRAKES - ABS5-93
Page 205 of 2339

(1) Lubricate the sensor O-ring with Mopar Wheel
Bearing Grease before installation into the Hub And
Bearing.If not lubricated, an improper seal may
result due to rolling of the O-ring.
(2) If metal sensor retaining clip is not in the neu-
tral installed position on hub and bearing cap, install
from the bottom, if necessary, and push clip upward
until it snaps into position.
(3) Install wheel speed sensor head into rear of
hub and bearing aligning index tab with the notch in
the top of the mounting hole. Push the sensor in
until it snaps into place on the metal retaining clip.
(4)
Install secondary (yellow) retaining clip over wheel
speed sensor head and engage the tabs on each side.
(5) Route sensor cable under leaf spring along rear
of axle. Install speed sensor cable into routing clips
on rear brake flex hose (Fig. 3).
(6) Install cable into metal routing clip and attach
it to the rear axle with mounting bolt (Fig. 3).
Tighten mounting bolt to 16 N´m (140 in. lbs.).
(7) Connect wheel speed sensor cable to vehicle
wiring harness (Fig. 2).Be sure speed sensor
cable connector is fully seated and locked into
vehicle wiring harness connector.
(8)
Install speed sensor cable grommet into hole in
floor pan making sure grommet is fully seated into hole.
(9) Lower vehicle.
(10) Road test vehicle to ensure proper operation
of the base and ABS braking systems.
TONE WHEEL
INSPECTION - TONE WHEEL
NOTE: Rear tone wheels for front-wheel-drive vehi-
cles are sealed within the hub and bearing assem-
bly and cannot be inspected or replaced.
Replacement of the hub and bearing is necessary.
Tone wheels can cause erratic wheel speed sensor
signals. Inspect tone wheels for the following possible
causes.
²missing, chipped, or broken teeth
²contact with the wheel speed sensor
²wheel speed sensor to tone wheel alignment
²wheel speed sensor to tone wheel clearance
²excessive tone wheel runout
²tone wheel loose on its mounting surface
If a front tone wheel is found to need replacement,
the drive shaft must be replaced. No attempt should
be made to replace just the tone wheel. (Refer to 3 -
DIFFERENTIAL & DRIVELINE/HALF SHAFT -
REMOVAL)
If a rear tone wheel is found to need replacement
on an all-wheel-drive model, the drive shaft must be
replaced. No attempt should be made to replace justthe tone wheel. (Refer to 3 - DIFFERENTIAL &
DRIVELINE/HALF SHAFT - REMOVAL)
If wheel speed sensor to tone wheel contact is evi-
dent, determine the cause and correct it before
replacing the wheel speed sensor or tone wheel.
Check the gap between the speed sensor head and
the tone wheel to ensure it is within specifications.
(Refer to 5 - BRAKES - ABS/ELECTRICAL - SPEC-
IFICATIONS)
Excessive wheel speed sensor runout can cause
erratic wheel speed sensor signals. Refer to SPECI-
FICATIONS in this section of the service manual for
the maximum allowed tone wheel runout (Refer to 5 -
BRAKES - ABS/ELECTRICAL - SPECIFICATIONS).
If tone wheel runout is excessive, determine if it is
caused by a defect in the driveshaft assembly or hub
and bearing. Replace as necessary.
Tone wheels are pressed onto their mounting sur-
faces and should not rotate independently from the
mounting surface. Replacement of the front drive-
shaft, rear driveshaft (AWD only) or rear hub and
bearing is necessary.
TRACTION CONTROL SWITCH
DIAGNOSIS AND TESTING - TRACTION
CONTROL SWITCH
(1) Remove lower steering column shroud. (Refer
to 19 - STEERING/COLUMN/LOWER SHROUD -
REMOVAL)
Fig. 5 Traction Control And Autostick Wiring
Connections
1 - TRACTION CONTROL WIRING CONNECTOR
2 - ROUTING CLIP
3 - AUTOSTICK WIRING CONNECTOR
4 - COLUMN WIRING HARNESS
5 - 94 BRAKES - ABSRS
REAR WHEEL SPEED SENSOR - FWD (Continued)
Page 206 of 2339

(2) Disconnect traction control switch harness from
column harness (Fig. 5).
(3) Using an ohmmeter, check for continuity
between pins 1 and 2. With the switch actuated,
there should be continuity between the two pins.
With the switch off, there should be no continuity.
REMOVAL
The traction control switch is located in the upper
shroud. (Refer to 19 - STEERING/COLUMN/UPPER
SHROUD - REMOVAL)
INSTALLATION
The traction control switch is located in the upper
shroud. (Refer to 19 - STEERING/COLUMN/UPPER
SHROUD - INSTALLATION)
HYDRAULIC/MECHANICAL
OPERATION - HYDRAULIC CIRCUITS AND
VALVES
The hydraulic fluid control valves control the flow
of pressurized brake fluid to the wheel brakes during
the different modes of ABS braking. The following
paragraphs explain how this works. For purposes of
explanation only, it is assumed that only the right
front wheel is experiencing antilock braking; the fol-
lowing diagrams show only the right front wheel in
an antilock braking operation.
NORMAL BRAKING HYDRAULIC CIRCUIT AND
SOLENOID VALVE FUNCTION
The hydraulic diagram (Fig. 6) shows the vehicle in
the normal braking mode of the base brake hydraulic
system. The diagram shows no wheel spin or slip
occurring relative to the speed of the vehicle. The
driver is applying the brake pedal which builds pres-
sure in the brake hydraulic system to engage the
brakes and stop the vehicle.
Fig. 6 Normal Braking Hydraulic Circuit
1 - OUTLET VALVE
2 - PUMP PISTON
3 - PUMP MOTOR (OFF)
4 - LOW PRESSURE ACCUMULATOR
5 - NORMALLY CLOSED VALVE (OFF)6 - TO RIGHT FRONT WHEEL
7 - NORMALLY OPEN VALVE (OFF)
8 - MASTER CYLINDER PRESSURE
9 - FROM MASTER CYLINDER
10 - NOISE DAMPER CHAMBER
RSBRAKES - ABS5-95
TRACTION CONTROL SWITCH (Continued)
Page 207 of 2339

ABS PRIMARY HYDRAULIC CIRCUIT AND
SOLENOID VALVE FUNCTION (ABS WITHOUT
TRACTION CONTROL)
The hydraulic diagram (Fig. 7) shows the vehicle in
the ABS braking mode. The diagram shows 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.
²The normally open and normally closed valves
modulate (build/decay) the brake hydraulic pressure
as required.
²The pump/motor is switched on so that the
brake fluid from the low pressure accumulators is
returned to the master cylinder circuits.
²The brake fluid is routed to either the master
cylinder or the wheel brake depending on the posi-
tion of the normally open valve.
Fig. 7 ABS Without Traction Control - Primary Hydraulic Circuit
1 - OUTLET VALVE
2 - PUMP PISTON
3 - PUMP MOTOR (ON)
4 - LOW PRESSURE ACCUMULATOR PRESSURE
5 - LOW PRESSURE ACCUMULATOR
6 - NORMALLY CLOSED VALVE (MODULATING)
7 - TO RIGHT FRONT WHEEL8 - NORMALLY OPEN VALVE (MODULATING)
9 - FROM MASTER CYLINDER
10 - MASTER CYLINDER PRESSURE
11 - CONTROLLED WHEEL PRESSURE
12 - PUMP INTERSTAGE PRESSURE
13 - NOISE DAMPER CHAMBER
5 - 96 BRAKES - ABSRS
HYDRAULIC/MECHANICAL (Continued)
Page 208 of 2339

ABS SECONDARY HYDRAULIC CIRCUIT AND
SOLENOID VALVE FUNCTION (ABS WITHOUT
TRACTION CONTROL)
The hydraulic diagram (Fig. 8) shows the vehicle in
the ABS braking mode. The diagram shows 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.
²The normally open and normally closed valves
modulate (build/decay) the brake hydraulic pressure
as required.²The pump/motor is switched on so that the
brake fluid from the low pressure accumulators is
returned to the master cylinder circuits.
²The brake fluid will then be routed to either the
master cylinder or the wheel brake depending on the
position of the normally open valve.
²In the secondary circuit, 1.2 cc brake fluid is
taken in by the lip seal saver to protect the lip seals
on the master cylinder piston.
Fig. 8 ABS Without Traction Control - Secondary Hydraulic Circuit
1 - OUTLET VALVE
2 - PUMP PISTON
3 - LOW PRESSURE ACCUMULATOR PRESSURE
4 - TO RIGHT FRONT WHEEL
5 - FROM MASTER CYLINDER6 - MASTER CYLINDER PRESSURE
7 - CONTROLLED WHEEL PRESSURE
8 - PUMP INTERSTAGE PRESSURE
9 - LIP SEAL SAVER (SECONDARY CIRCUIT ONLY)
RSBRAKES - ABS5-97
HYDRAULIC/MECHANICAL (Continued)