lock CHRYSLER VOYAGER 1996 Workshop Manual

fluid accumulators temporarily store brake fluid that
is decayed from the wheel brakes during an ABS
cycle. This stored brake fluid is then used by the
pump in the HCU to provide build pressure for the
brake hydraulic system.
Additionally on vehicles that are equipped with
only ABS (non-traction control vehicles) there is a
mini brake fluid accumulator on the secondary
hydraulic circuit which protects the master cylinder's
seals during an ABS stop. There is also a noise
damping chamber on the primary hydraulic circuit.
On ABS equipped vehicles with traction control, in
addition to the brake fluid accumulators there are
also two noise damping chambers in the HCU.
HCU PUMP/MOTOR
The HCU (Fig. 4) contains 2 pump assemblies, one
for the primary and one for the secondary hydraulic
circuit of the brake system. Both pumps are driven
by a common electric motor (Fig. 4) which is part of
the HCU. The pumps draw brake fluid from the fluid
accumulators to supply build pressure to the brakes
during an ABS stop. The pump motor runs during
the drive-off cycle as a check and during an ABS stop
and is controlled by the CAB. The Pump/Motor
Assembly is not a serviceable item. If the pump/mo-
tor requires replacement the complete HCU (Fig. 4)
(minus the CAB) must be replaced.
ABS FUSES
The fuse for the ABS pump motor and the ABS system
are located in the power distribution center (PDC) (Fig. 5).
The PDC is located on the drivers side of the engine com-
partment forward of the strut tower. The fuse for the ABS
warning lamp in the instrument panel message center is
located in the junction block.
On vehicles equipped with traction control, the
fuse for the traction control switch is also located in
the junction block.The junction block is located on the left hand front
cowl panel on the vehicle.
ABS RELAYS
On the Teves Mark 20 Antilock Brake System both
the pump motor relay and the system relay are
located in the CAB. If either of the relays is diag-
nosed as not functioning properly the CAB will need
to be replaced. Refer to Controller Antilock Brakes in
the Removal And Installation Section in this group of
the service manual for the procedure.
PROPORTIONING VALVES
One assembly containing two proportioning valves
are used in the system, one for each rear brake
hydraulic circuit. The proportioning valve is located
on the frame rail next to the fuel tank, forward of the
right rear shock absorber (Fig. 6). Be sure replace-
ment proportioning valve assemblies have the same
split point and slope as the proportioning valve being
replaced.
WHEEL SPEED SENSORS
One Wheel Speed Sensor WSS is located at each
front and rear wheel of the vehicle (Fig. 7), (Fig. 8)
and (Fig. 9). The wheel speed sensor sends a small
AC signal to the CAB. This signal is generated by
magnetic induction created when a toothed sensor
ring (tone wheel) (Fig. 7), (Fig. 8) and (Fig. 9) passes
the stationary magnetic wheel speed sensor. The
CAB converts the AC signal generated at each wheel
into a digital signal. 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.
Fig. 4 Teves Mark 20 HCU Pump/Motor
Fig. 5 Fuse Locations In Power Distribution Center
NSBRAKES 5 - 89
DESCRIPTION AND OPERATION (Continued)

The front wheel speed sensor is attached to a boss
in the steering knuckle (Fig. 7). The front tone wheel
(Fig. 7) is part of the driveshafts outboard constant
velocity joint. The rear wheel speed sensor ismounted through the rear axle, rear brake support
plate and directly to the rear bearing (Fig. 8) (Fig. 9).
The rear tone wheel on a front wheel drive vehicle is
an integral part of the rear wheel hub/bearing
assembly. If damaged though, the rear tone wheel on
a front wheel drive vehicle can be replaced as a indi-
vidual component of the rear hub/bearing assembly.
Refer to Rear Tone Wheel in the Remove And Install
Section in this group of the service manual for the
required procedure. The wheel speed sensor air gap
is NOT adjustable.
The rear tone wheel on a all wheel drive vehicle, is
part of the outboard constant velocity joint on the
rear driveshaft (Fig. 9).
The four wheel speed sensors are all serviced indi-
vidually, but the front tone wheel on all vehicles and
the rear tone wheel on all wheel drive vehicles are
serviced as part of the front or rear driveshaft out-
board constant velocity joint (Fig. 7) and (Fig. 9).
Correct ABS system operation is dependent on
accurate wheel speed signals. The vehicle's wheels
and tires must all be the same size and type to gen-
erate accurate signals. Variations in wheel and tire
size can produce inaccurate wheel speed signals,
which can cause false ABS cycles to occur.
CONTROLLER ANTILOCK BRAKES (CAB)
The Controller Antilock Brakes (CAB) is a micro-
processor based device which monitors the ABS sys-
tem during normal braking and controls it when the
vehicle is in an ABS stop. The CAB is mounted to the
bottom of the HCU (Fig. 10). 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 CCD BUS
Fig. 6 Proportioning Valve Mounting Location
Fig. 7 Front Wheel Speed Sensor
Fig. 8 Rear Wheel Speed Sensor (FWD)
Fig. 9 Rear Wheel Speed Sensor (AWD)
5 - 90 BRAKESNS
DESCRIPTION AND OPERATION (Continued)

The primary functions of the (CAB) are:
(1) Detect wheel locking or wheel slipping tenden-
cies by monitoring the speed of all four wheels of the
vehicle.
(2) Illuminate the TRAC lamp in the message cen-
ter on the instrument panel when a traction control
event is occurring.
(3) Control fluid modulation to the wheel brakes
while the system is in an ABS mode or the traction
control system is activated.
(4) Monitor the system for proper operation.
(5) Provide communication to the DRB Scan Tool
while in diagnostic mode.
(6) Store diagnostic information.
(7)The CAB continuously communicates with
the body controller by sending out a message to
the body controller on the CCD Bus. This mes-
sage is used for illumination of the yellow
antilock warning lamp. This is used if the ABS
controller communication is lost in the hard
wire between the body controller and the yel-
low antilock warning lamp. If the body control-
ler does not receive this message from the CAB,
the body controller will illuminate the antilock
yellow warning lamp.
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 which 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 ABS system is constantly monitored by the
CAB for proper operation. If the CAB detects a fault,
it will turn on the Amber ABS Warning Lamp anddisable the ABS braking system. The normal base
braking system will remain operational.
The CAB contains a self-diagnostic program which
will turn on the Amber ABS Warning Lamp when a
ABS system fault is detected. Faults are then stored
in a diagnostic program memory. There are multiple
fault messages which may be stored in the CAB and
displayed through the DRB Scan Tool. These fault
messages will remain in the CAB memory even after
the ignition has been turned off. The fault messages
can be read and or cleared from the CAB memory by
a technician using the DRB Scan Tool. The fault
occurrence and the fault code will also be automati-
cally cleared from the CAB memory after the identi-
cal fault has not been seen during the next 3500
miles of vehicle operation. Mileage though of the last
fault occurrence will not be automatically cleared.CONTROLLER ANTILOCK BRAKE INPUTS
²Four wheel speed sensors.
²Stop lamp switch.
²Ignition switch.
²System relay voltage.
²Ground.
²Traction Control Switch (If Equipped).
²Diagnostics Communications (CCD)
CONTROLLER ANTILOCK BRAKE OUTPUTS
²C2D Communication To Body Controller And
Instrument Cluster
²ABS warning lamp actuation.
²Traction Control Light (If Equipped).
²Diagnostic communication. (CCD)
ABS WARNING LAMP (YELLOW)
The ABS system uses a yellow colored ABS Warn-
ing Lamp. The ABS warning lamp is located on the
right side of the message center located at the top of
the instrument panel. The purpose of the warning
lamp is discussed in detail below.
The ABS warning lamp will turn on when the CAB
detects a condition which results in a shutdown of
ABS function or when the body controller does not
receive C2D messages from the CAB. When the igni-
tion key is turned to the on position, the ABS Warn-
ing Lamp is on until the CAB completes its self tests
and turns the lamp off (approximately 4 seconds
after the ignition switch is turned on). Under most
conditions, when the ABS warning lamp is on, only
the ABS function of the brake system is affected. The
standard brake system and the ability to stop the car
will not be affected when only the ABS warning lamp
is on.
The ABS warning lamp is controlled by the CAB
and the body controller through a diode located in
the wiring harness junction block. The junction block
is located under the instrument panel to the left of
Fig. 10 Controller Antilock Brake (CAB)
NSBRAKES 5 - 91
DESCRIPTION AND OPERATION (Continued)

the steering column. The CAB and the body control-
ler, controls the yellow ABS warning lamp by directly
grounding the circuit.
HYDRAULIC CIRCUITS AND VALVE OPERATION
Through the following operation descriptions the
function of the various hydraulic control valves in the
ABS will be described. The fluid control valves men-
tioned below, control the flow of pressurized brake
fluid to the wheel brakes during the different modes
of ABS braking.
For explanation purposes, all wheel speed sensors
except the right front are sending the same wheel
speed information. The following diagrams show only
the right front wheel in a antilock braking condition.
NORMAL BRAKING HYDRAULIC CIRCUIT AND
SOLENOID VALVE FUNCTION
This condition is the normal operation of the vehi-
cles base brake hydraulic system. The hydraulic sys-
tem circuit diagram (Fig. 11) shows a situation where
no wheel spin or slip is occurring relative to the
speed of the vehicle. The driver is applying the brake
pedal to build pressure in the brake hydraulic system
to apply the brakes and stop the vehicle.
TEVES MARK 20 ABS CIRCUIT AND
SOLENOID VALVE FUNCTION
This hydraulic circuit diagram (Fig. 12) shows the
vehicle in the ABS braking mode. This hydraulic cir-
cuit (Fig. 12) shows a situation where one wheel is
slipping because the driver is attempting to stop the
vehicle at a faster rate than the surface the vehicle's
tires are on will allow. The normally open and nor-
mally closed valves modulate the brake hydraulic
pressure as required. The pump/motor is switched on
so that the brake fluid from the low pressure accu-
mulators is returned to the master cylinder circuits.
The brake fluid will then be routed to either the mas-
ter cylinder or the wheel brake depending on the
position of the normally open valve.
TEVES MARK 20 SECONDARY ABS CIRCUIT
AND SOLENOID VALVE FUNCTION
This hydraulic circuit diagram (Fig. 13) shows the
vehicle in the ABS braking mode. This hydraulic cir-
cuit (Fig. 13) shows a situation where one wheel is
slipping because the driver is attempting to stop the
vehicle at a faster rate than the surface the vehicle's
tires are on will allow. The normally open and nor-
mally closed valves modulate the brake hydraulic
pressure as required. The pump/motor is switched on
so that the brake fluid from the low pressure accu-
Fig. 11 Normal Braking Hydraulic Circuit
5 - 92 BRAKESNS
DESCRIPTION AND OPERATION (Continued)

TEVES MARK 20 ABS WITH TRACTION
CONTROL± TRACTION CONTROL HYDRAULIC
CIRCUIT ± SOLENOID AND SHUTTLE VALVE
FUNCTION
This hydraulic circuit diagram (Fig. 16) shows a
vehicle equipped with ABS and traction control in
the traction control mode. The hydraulic circuit (Fig.
16) shows a situation where a driven wheel is spin-
ning and brake pressure is required to reduce its
speed. The normally open ASR valve (Fig. 16) is ener-
gized to isolate the brake fluid being pumped from
the master cylinder and to isolate the driven wheel.
Also, the normally open ASR valve bypasses the
pump output back to the master cylinder at a fixed
pressure setting. The normally open and normally
closed valves (Fig. 16) modulate the brake pressure
as required to the spinning wheel.
DIAGNOSIS AND TESTING
ABS GENERAL DIAGNOSTICS INFORMATION
This section contains the information necessary to
diagnose the ITT Teves Mark 20 ABS Brake System.
Specifically, this section should be used to help diag-
nose conditions which result in any of the following:
(1) ABS Warning Lamp turned on.(2) Brakes Lock-up on hard application
Diagnosis of base brake conditions which are obvi-
ously mechanical in nature should be directed to
Group 5 Brakes in this service manual. This includes
brake noise, brake pulsation, lack of power assist,
parking brake, Red BRAKE Warning Lamp lighting,
or vehicle vibration during normal braking.
Many conditions that generate customer com-
plaints may be normal operating conditions, but are
judged to be a problem due to not being familiar with
the ABS system. These conditions can be recognized
without performing extensive diagnostic work, given
adequate understanding of the operating principles
and performance characteristics of the ABS. See the
ABS System Operation Section in this group of the
service manual to familiarize yourself with the oper-
ating principles of the ABS system.
ABS WIRING DIAGRAM INFORMATION
During the diagnosis of the antilock brake system
it may become necessary to reference the wiring dia-
grams covering the antilock brake system and its
components. For wiring diagrams refer to Antilock
Brakes in Group 8W of this service manual. This
group will provide you with the wiring diagrams and
the circuit description and operation information cov-
ering the antilock brake system.
Fig. 15 ABS With Traction Control ABS Braking Hydraulic Circuit
NSBRAKES 5 - 95
DESCRIPTION AND OPERATION (Continued)

START-UP CYCLE
The self diagnostic ABS start up cycle begins when
the ignition switch is turned to the on position. Elec-
trical checks are completed on ABS components, such
as the Controller, solenoid continuity, and the system
relay operation. During this check the Amber ABS
Warning Light is turned on for approximately 4 sec-
onds and the brake pedal may emit a popping sound
and move slightly when the solenoid valves are
checked.
DRIVE-OFF CYCLE
Further Functional testing is accomplished once
the vehicle is set in motion and reaches a speed of
about 20 kph (12 mph.). This cycle is performed only
once after each ignition on/off cycle.
²The pump/motor is activated briefly to verify
function. When the pump/motor is activated a whirl-
ing or buzzing sound may be heard by the driver,
which is normal when the pump/motor is running.
²The wheel speed sensor output is verified to be
within the correct operating range.
ONGOING TESTS
Other tests are performed on a continuous basis.
These include checks for solenoid continuity, wheel
speed sensor continuity and wheel speed sensor out-
put.
ABS DIAGNOSTIC TROUBLE CODES
Diagnostic trouble codes (DTC) are kept in the con-
troller's memory until either erased by the technician
using the DRB or erased automatically after 3500
miles. DTC's are retained by the controller even if
the ignition is turned off or the battery is discon-
nected. More than one DTC can be stored at a time.
The mileage of the most recent occurrence, number of
occurrences and the DTC that was stored is also dis-
played. Most functions of the CAB and the ABS sys-
tem can be accessed by the technician for testing and
diagnostic purposes by using the DRB.
LATCHING VERSUS NON-LATCHING
DIAGNOSTIC TROUBLE CODES
Some DTC's detected by the CAB are latching; the
DTC is latched and ABS braking is disabled 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 lights
that are turned on, are only turned on as long as the
DTC condition exists. As soon as the condition goes
away, the ABS Warning Light is turned off, although
a DTC will be set in most cases.
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. When an
intermittent fault is encountered, check suspect cir-
cuits for:
A visual inspection for loose, disconnected, or mis-
routed wires should be done before attempting to
diagnose or service the ITT Teves Mark 20 antilock
brake system. A visual inspection will eliminate
unnecessary testing and diagnostics time. A thorough
visual inspection will include the following compo-
nents and areas of the vehicle.
(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 wring junc-
tion block. A label on the underside of the PDC cover
identifies the locations of the ABS fuses in the PDC.
(2) Inspect the 25-way electrical connector at the
CAB for damage, spread or backed-out wiring termi-
nals. Verify that the 25-way connector is fully
inserted in the socket on the CAB. Be sure that wires
are not stretched tight or pulled out of the connector.
(3) Verify that all the wheel speed sensor connec-
tions are secure.
(4) Poor mating of connector halves or terminals
not fully seated in the connector body.
(5) Improperly formed or damaged terminals. All
connector terminals in a suspect circuit should be
carefully reformed to increase contact tension.
(6) Poor terminal to wire connection. This requires
removing the terminal from the connector body to
inspect.
(7) Pin presence in the connector assembly
(8) Proper ground connections. Check all ground
connections for signs of corrosion, tight fasteners, or
other potential defects. Refer to wiring diagram man-
ual for ground locations.
(9) Problems with main power sources of the vehi-
cle. Inspect battery, generator, ignition circuits and
other related relays and fuses.
(10) If a visual check does not find the cause of the
problem, operate the car in an attempt to duplicate
the condition and record the trouble code.
(11) Most failures of the ABS system will disable
ABS function for the entire ignition cycle even if the
fault clears before key-off. There are some failure
conditions, however, which will allow ABS operation
to resume during the ignition cycle in which a failure
occurred if the failure conditions are no longer
present. The following conditions may result in inter-
mittent illumination of the ABS Warning Lamp. All
other failures will cause the lamp to remain on until
the ignition switch is turned off. Circuits involving
NSBRAKES 5 - 97
DIAGNOSIS AND TESTING (Continued)

these inputs to the CAB should be investigated if a
complaint of intermittent warning system operation
is encountered.
(12) Low system voltage. If Low System Voltage is
detected by the CAB, the CAB will turn on the ABS
Warning Lamp until normal system voltage is
achieved. Once normal voltage is seen at the CAB,
normal operation resumes.
(13) High system voltage. If high system voltage is
detected by the CAB, the CAB will turn on the
Amber ABS Warning Lamp until normal system volt-
age is achieved. Once normal voltage is again
detected by the CAB, normal ABS operation will be
resumed at the next key on cycle.
(14) Additionally, any condition which results in
interruption of electrical current to the CAB or mod-
ulator assembly may cause the ABS Warning Lamp
to turn on intermittently.
(15) The body controller can turn on the (yellow)
ABS warning lamp if CCD communication between
the body controller and the CAB is interupted.
TONEWHEEL INSPECTION
CAUTION: The tone wheels used on this vehicle
equipped with the Teves Mark 20 Antilock Brake
System are different then those used on past mod-
els of this vehicle equipped with antilock brakes.
Reduced braking performance will result if this part
is used on earlier model vehicles and an accident
could result. Do not use on pre-1998 model year
vehicles.
Carefully inspect tonewheel at the suspected faulty
wheel speed sensor for missing, chipped or broken
teeth, this can cause erratic speed sensor signals.
Tonewheels should show no evidence of contact
with the wheel speed sensors. If contact was made,
determine cause and correct before replacing the
wheel speed sensor.
Excessive runout of the tonewheel can cause
erratic wheel speed sensor signals. Refer to Tone-
wheel Runout in the Specification Section in this sec-
tion of the service manual for the tonewheel runout
specification. Replace drive shaft assembly or rear
hub/bearing assembly if tonewheel runout exceeds
the specification.
Inspect tonewheels for looseness on their mounting
surfaces. Tonewheels are pressed onto their mounting
surfaces and should not rotate independently from
the mounting surface.
Check the wheel speed sensor head alignment to
the tone wheel. Also check the gap between the speed
sensor head and the tone wheel to ensure it is at
specification. Refer to Wheel Speed Sensor Clearance
in the Specification Section in this section of the ser-
vice manual.
PROPORTIONING VALVE
CAUTION: Proportioning valves (Fig. 18) should
never be disassembled.
If premature rear wheel skid occurs on hard brake
application, it could be an indication that a malfunc-
tion has occurred with one of the proportioning
valves.
If a malfunctioning proportioning valve is sus-
pected on a vehicle, refer to Proportioning Valve Test
in the Proportioning Valves Section in this group of
the service manual for the required test procedure.
BRAKE FLUID CONTAMINATION
Indications of fluid contamination are swollen or
deteriorated rubber parts.
Swollen rubber parts indicate the presence of
petroleum in the brake fluid.
To test for contamination, put a small amount of
drained brake fluid in clear glass jar. If fluid sepa-
rates into layers, there is mineral oil or other fluid
contamination of the brake fluid.
If brake fluid is contaminated, drain and thor-
oughly flush system. Replace master cylinder, propor-
tioning valve, caliper seals, wheel cylinder seals,
Antilock Brakes hydraulic unit and all hydraulic
fluid hoses.
TEST DRIVING ABS COMPLAINT VEHICLE
Most ABS complaints will require a test drive as a
part of the diagnostic procedure. The purpose of the
test drive is to duplicate the condition.
NOTE: Remember conditions that result in the
turning on of the Red BRAKE Warning Lamp may
indicate reduced braking ability. The following pro-
cedure should be used to test drive an ABS com-
plaint vehicle.
Fig. 18 Brake Proportioning Valve Identification
5 - 98 BRAKESNS
DIAGNOSIS AND TESTING (Continued)

Before test driving a brake complaint vehicle, note
whether the Red or Amber Brake Warning Lamp is
turned on. If it is the Red Brake Warning Lamp,
refer to the hydraulic system section in the brake
group of this manual. If the ABS Warning lamp
was/is on, test drive the vehicle as described below, to
verify the complaint. While the ABS Warning Lamp
is on, the ABS is not functional. The standard brake
system and the ability to stop the car may not be
affected if only the ABS Warning Lamp is on.
Discuss with the owner of the vehicle or note any
other electrical problems or conditions that may be
occurring on the vehicle. They may have an effect on
the antilock brake system's function.
(1) Turn the key to the off position and then back
to the on position. Note whether the ABS Warning
Lamp continues to stay on. If it does, refer to the
diagnostic manual covering the ITT Teves Mark 20
ABS system for the required test procedures.
(2) If the ABS Warning Lamp goes out, shift into
gear and drive the car to a speed of 20 kph (12 mph)
to complete the ABS start up cycle. If at this time the
ABS Warning Lamp goes on refer to the ITT Teves
Mark 20 Diagnostic Manual.
(3) If the ABS Warning Lamp remains OUT, drive
the vehicle a short distance. During this test drive be
sure that the vehicle achieves at least 40 mph. Brake
to at least one complete stop in an ABS cycle, and
again accelerate to 25 mph.
(4) If a functional problem with the ABS system is
determined while test driving a vehicle, refer to the
diagnostic manual covering the ITT Teves Mark 20
ABS system for the required test procedures and
proper use of the DRB diagnostic scan tool.
ABS SERVICE PRECAUTIONS
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.In testing for open or short circuits, do
not ground or apply voltage to any of the cir-
cuits unless instructed to do so for a diagnostic
procedure.These circuits should only be tested
using a high impedance multi-meter or the DRB
tester 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: Use only factory wiring harnesses. Do
not cut or splice wiring to the brake circuits. The
addition of after-market electrical equipment (car
phone, radar detector, citizen band radio, trailer
lighting, trailer brakes, ect.) on a vehicle equippedwith antilock brakes may affect the function of the
antilock brake system.
SERVICE PROCEDURES
BRAKE FLUID LEVEL INSPECTION
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.
For the specific procedure covering the inspection
of the brake fluid level and adding brake fluid to the
reservoir, refer to the Service Adjustments Section in
this group of the service manual.
BLEEDING TEVES MARK 20 HYDRAULIC SYSTEM
The base brake system must be bled anytime air is
permitted to enter the hydraulic system, due to dis-
connection of brake lines, hoses or components. The
ABS system, particularly the HCU, should only be
bled when the HCU is replaced or removed from the
vehicle, or if there is reason to believe the HCU has
ingested air. Under most circumstances that would
require brake bleeding, only the base brake 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 bleeding operations, be sure that the brake
fluid level remains close to the FULL level in the res-
ervoir. Check the fluid level periodically during the
bleeding procedure and add DOT 3 brake fluid as
required.
The Teves Mark 20 ABS hydraulic system and the
base brake hydraulic system must be bled as two
independent braking systems. The non ABS portion
of the brake system is to be bled the same as any
non ABS system. Refer to the Service Adjustments
section in this manual for the proper bleeding proce-
dure to be used. This brake system can be either
pressure bled or manually bled.
The ABS portion of the brake system MUST be
bled separately. This bleeding procedure requires the
use of the DRB Diagnostic Tester and the bleeding
sequence procedure outlined below.
ABS BLEEDING PROCEDURE
When bleeding the ABS system, the following
bleeding sequenceMUSTbe followed to insure com-
plete and adequate bleeding. The ABS system can be
bled using a manual bleeding procedure or standard
pressure bleeding equipment.
NSBRAKES 5 - 99
DIAGNOSIS AND TESTING (Continued)

If the brake system is to be bled using pressurized
bleeding equipment, refer to Bleeding Brake System
in the Service Adjustments section at the beginning
of this group for proper equipment usage and proce-
dures.
(1) Assemble and install all brake system compo-
nents on the vehicle making sure all hydraulic fluid
lines are installed and properly torqued.
(2) Connect the DRB Diagnostics Tester to the
diagnostics connector. The Teves Mark 20 ABS diag-
nostic connector is located under the instrument
panel to the left of the steering column cover.
(3) Using the DRB, check to make sure the CAB
does not have any fault codes stored. If it does,
remove them using the DRB.
WARNING: WHEN BLEEDING THE BRAKE SYS-
TEM WEAR SAFETY GLASSES. A CLEAR BLEED
TUBE MUST BE ATTACHED TO THE BLEEDER
SCREWS AND SUBMERGED IN A CLEAR CON-
TAINER FILLED PART WAY WITH CLEAN BRAKE
FLUID. DIRECT THE FLOW OF BRAKE FLUID AWAY
FROM THE PAINTED SURFACES OF THE VEHICLE.
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 the Service Adjustments section of this
service manual.
(5) Using the DRB, go to the9Bleed ABS9routine.
Apply the brake pedal firmly and initiate the9Bleed
ABS9cycle one time. Release the brake pedal.
(6) Bleed the base brake system again, as in step
Step 4 above.
(7) Repeat steps Step 5 and Step 6 above until
brake fluid flows clear and is free of any air bubbles.
Check brake fluid level in reservoir periodically to
prevent reservoir from running low on brake fluid.
(8) Test drive the vehicle to be sure brakes are
operating correctly and that brake pedal is solid.
REMOVAL AND INSTALLATION
ABS GENERAL SERVICE PRECAUTIONS
CAUTION: Review this entire section prior to per-
forming any mechanical work on a vehicle equipped
with the ITT Tevis Mark 20 ABS brake system. This
section contains information on precautions per-
taining to potential component damage, vehicle
damage 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: Certain components of the ABS System
are not intended to be serviced individually.
Attempting to remove or disconnect certain system
components may result in improper system opera-
tion. 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 CAB. Doing this will damage the pump
motor and will require replacement of the HCU.
The following are general cautions which should be
observed when servicing the ABS system and/or
other vehicle systems. Failure to observe these pre-
cautions may result in ABS System component dam-
age.
If welding work is to be performed on the vehicle,
using an electric arc welder, the CAB connector
should be disconnected during the welding operation.
The CAB 25 way connector 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.
HYDRAULIC CONTROL UNIT
REMOVE
(1) Disconnect the negative (ground) cable from
the battery and isolate cable.
(2) Using a brake pedal depressor, move and lock
the brake pedal to a position past the first inch of
pedal travel.This will prevent brake fluid from
draining out of the master cylinder when the
brake tubes are removed from the HCU.
(3) Raise vehicle. Vehicle is to be raised and sup-
ported on jackstands or on a frame contact type
5 - 100 BRAKESNS
SERVICE PROCEDURES (Continued)

hoist. See Hoisting in the Lubrication And Mainte-
nance section of this service manual.
(4) Remove the routing clip attaching the HCU
wiring harness to the HCU mounting bracket (Fig.
19).
CAUTION: Do not apply a 12 volt power source to
any terminals of the 25 way HCU connector when
disconnected.
(5) Remove the 25 way connector (Fig. 19) from
the CAB. The 25 way connector is removed from the
CAB using the following procedure. Grasp the lock
on the 25 way connector (Fig. 19) and pull it as far
out as possible (Fig. 20). This will raise and unlock
the 25 way connector from the socket on the CAB.
CAUTION: Before removing the brake tubes from
the HCU, the HCU must be thoroughly cleaned. This
must be done to prevent dirt particles from falling
into the ports of HCU or entering the brake tubes.(6) Thoroughly clean all surfaces of the HCU, and
all brake tube nuts located on the HCU. Use only a
solvent such as Mopar Brake Parts Cleaner or an
equivalent to clean the HCU.
(7) Remove the brake tubes (6) from the inlet and
outlet ports on the HCU. (Fig. 21).
(8) Remove the 3 bolts (Fig. 22) attaching the
HCU mounting bracket to the front suspension cross-
member.
(9) Remove HCU and the mounting bracket as a
unit from the vehicle.
(10) Remove the 3 bolts (Fig. 23) mounting the
HCU to the mounting bracket. Separate the HCU
from the mounting bracket.
(11) Remove the CAB (Fig. 19) from the bottom of
the HCU for installation on the replacement HCU.
Refer to Controller Antilock Brakes (CAB) in the
Removal And Installation Section in this group of the
service manual for the required procedure.
Fig. 19 CAB 25 Way Connector
Fig. 20 Unlocked 25 Way CAB Connector
Fig. 21 Brake Tube Connections To HCU
Fig. 22 HCU To Suspension Cradle Mounting Bolts
NSBRAKES 5 - 101
REMOVAL AND INSTALLATION (Continued)