Chrysler Voyager. Manual — part 428

1.0

INTRODUCTION

The procedures contained in this manual include

all the specifications, manuals, and graphics
needed to diagnose the 2003 Chrysler Town &
Country, Dodge Caravan, and Chrysler Voyager
Mark 20e Antilock Braking System (ABS), and
Mark 20e Antilocke Braking System with Traction
Control. The diagnostics in this instruction are based
on the failure condition or symptom being present
at time of diagnosis.

Please follow the recommendations below when

choosing your diagnostic path.

1. First make sure the DRBIII

t is communicating

with the CAB. If the DRBIII

t displays a “No

Response” condition, you must diagnose that
first.

2. Read DTC’s (diagnostic trouble codes) with the

DRBIII

t.

3. If no DTC’s are present, identify the customer

complaint.

4. Once the DTC or customer complaint is identi-

fied, locate the matching test in the Table of
Contents and begin to diagnose the symptom.

All component location views are in Section 8.0.

All connector pinouts are in Section 9.0. All sche-
matics are in Section 10.0.

An asterisk (*) placed before the symptom de-

scription indicates a concern with no associated
DTC.

When repairs are required, refer to the appropri-

ate service manual for the proper removal and
repair procedure.

Diagnostic procedures change every year. New

diagnostic systems may be added; carry over sys-
tems may be enhanced. READ THIS MANUAL
BEFORE TRYING TO DIAGNOSE A VEHICLE
CODE. It is recommended that you review the
entire manual to become familiar with all new and
changed diagnostic procedures.

After using this book, if you have any comments

or recommendations, please fill out the form at the
back of the book and mail it back to us.

1.1

SYSTEM COVERAGE

This diagnostic procedure manual covers the an-

tilock braking system (ABS), and the traction con-
trol system found on: Chrysler Town and Country,
Dodge Caravan, and Chrysler Voyager.

1.2

SIX-STEP TROUBLESHOOTING
PROCEDURE

Diagnosis of the controller antilock brake module

is done in six basic steps:

•

verification of complaint

•

verification of any related symptoms

•

symptom analysis

•

problem isolation

•

repair of isolated problem

•

verification of proper operation

2.0

IDENTIFICATION OF
SYSTEM

Vehicles equipped with the Teves Mark 20e an-

tilock brake system can be identified by the pres-
ence of the controller antilock brake module located
beneath the master cylinder.

The presence of the Traction Control system is

indicated by the TRAC OFF switch on top of the
steering column shroud.

3.0

SYSTEM DESCRIPTION AND
FUNCTIONAL OPERATION

3.1

TEVES MARK 20e SYSTEM
DESCRIPTION

The controller antilock brake module is used to

monitor wheel speeds and to modulate (control)
hydraulic pressure in each brake channel. The
modulated hydraulic pressure is used to prevent
wheel lock-up during braking.

The Teves Mark 20e system uses a diagonal split

hydraulic brake system. In the standard brake
mode the master cylinder primary circuit supplies
pressure to the right front and left rear wheel
brakes, and the secondary master cylinder circuit
supplies pressure to the left front and right rear
wheel brakes.

All vehicles equipped with ABS use Electronic

Variable Brake Proportioning (EVPB) to balance
front-to-rear braking when brakes are applied in
the partial braking range.

3.2

TRACTION CONTROL SYSTEM (TCS)
DESCRIPTION (IF EQUIPPED)

The main purpose of traction control is to reduce

wheel slip and maintain traction at the driven
wheels when road surfaces are slippery. The trac-
tion control system reduces wheel slip by braking
the wheel that is losing traction. The system is
designed to operate at speeds below 56 km/h (35
mph).

1

GENERAL INFORMATION

3.3

SYSTEM COMPONENTS

ABS

•

controller antilock brake (CAB)

•

vacuum booster

•

master cylinder

•

ABS

integrated

electronic

control

module/

hydraulic control unit (HCU), valve block assem-
bly: 8 valve solenoids (4 inlet valves, 4 outlet
valves, 2 accumulators) 1 pump.

•

4 wheel speed sensor/tone wheel assemblies

•

ABS warning indicator

•

fuses and wiring harness

•

fluid reservoir

ABS With Traction Control

•

CAB with Traction Control programming

•

HCU with two additional control valves.

•

TRAC ON/OFF Switch

•

TRAC/TRAC OFF indicators

3.3.1

ABS AND BRAKE WARNING
INDICATORS

The amber ABS warning indicator is located in

the instrument cluster. It is used to inform the
driver that the antilock function has been turned
off. The ABS warning indicator is controlled by the
CAB. The CAB controls the lamp with a command
over the PCI bus.

The ABS Warning Indicator will remain lit during

every key cycle until a circuit or component fault is
repaired and the CAB no longer detects the fault.
After repair of a sensor signal fault or a pump motor
fault, the CAB must sense all four wheels at 25
km/h (15 mph) before it will extinguish the ABS and
TRAC OFF Indicators.

The Instrument Cluster will illuminate the ABS

Warning Indicator if it loses communication with
the CAB.

The red BRAKE warning indicator is also located

in the instrument cluster. It can be activated in
several ways. Application of the parking brake or a
low fluid signal from the fluid level switch located in
the master cylinder reservoir will cause the indica-
tor to come on.

3.3.2

CONTROLLER ANTILOCK BRAKE
(CAB)

The Controller Antilock Brake (CAB) is a

microprocessor-based device that monitors wheel
speeds and controls the antilock functions. The
CAB contains two microprocessors that receive
identical sensor signals and then independently

process the information. The results are then com-
pared to make sure that they agree. Otherwise, the
CAB will turn off the antilock and turn on the ABS
amber warning indicator.

The primary functions of the CAB are to:

•

detect wheel locking tendencies

•

control fluid pressure modulation to the brakes
during antilock stop

•

monitor the system for proper operation

•

manage traction control functions

•

provide communication to the DRBIII

t while in

diagnostic mode

•

store diagnostic information in non-volatile mem-
ory

The CAB continuously monitors the speed of each

wheel. When a wheel locking tendency is detected,
the CAB will command the appropriate valve to
modulate brake fluid pressure in its hydraulic unit.
Brake pedal position is maintained during an an-
tilock stop by being a closed system. The CAB
continues to control pressure in individual hydrau-
lic circuits until a wheel locking tendency is no
longer present. The CAB turns on the pump motor
during an antilock stop.

The antilock brake system is constantly moni-

tored by the CAB for proper operation. If the CAB
detects a system malfunction, it can disable the
antilock system and turn on the ABS warning
indicator. If the antilock function is disabled, the
system will revert to standard base brake system
operation.
The CAB inputs include the following:

•

diagnostic communication

•

four wheel speed sensors

•

three power feeds: valve, pump, and microproces-
sor

•

brake switch

•

traction control switch

The CAB outputs include the following:

•

ABS warning indicator actuation

•

12 volts power to wheel speed sensors

•

eight valves

•

ten valves with traction control

•

diagnostic communication

•

PCI bus communication

•

traction control lamp illumination

3.3.3

HYDRAULIC CONTROL UNIT

The hydraulic control unit (HCU) contains the

valve block assembly, and pump/motor assembly.
The HCU is attached to the CAB.

Valve Block Assembly: The valve block assem-

bly contains valves with four inlet valves and four

2

GENERAL INFORMATION

outlet valves. The inlet valves are spring-loaded in
the open position and the outlet valves are spring
loaded in the closed position. During an antilock
stop, these valves are cycled to maintain the proper
slip ratio for each wheel. If a wheel detects slip, the
inlet valve is closed to prevent and further pressure
increase. Then the outlet valve is opened to release
the pressure to the accumulators until the wheel is
no longer slipping. Once the wheel is no longer
slipping, the outlet valve is closed and the inlet
valve is opened to reapply pressure. If the wheel is
decelerating within its predetermined limits (prop-
er slip ratio), the inlet valve will close to hold the
pressure constant. On vehicles which are equipped
with a traction control system, there are two addi-
tional valves that isolate the master cylinder and
rear wheels. During a traction control event the
brakes are applied to reduce wheel slippage.

Pump Motor Assembly: The pump motor as-

sembly provides the extra amount of fluid needed
during antilock braking. The pump is supplied fluid
that is released to the accumulators when the outlet
valve is opened during an antilock stop. The pump
is also used to drain the accumulator circuits after
the antilock stop is complete. The pump is operated
by an integral electric motor. This motor is con-
trolled by the CAB. The CAB may turn on the pump
motor when an antilock stop is detected. The pump
continues to run during the antilock stop and is
turned off after the stop is complete. Under some
conditions, the pump motor will run to drain the
accumulators during the next drive off. The CAB
monitors the pump motor operation internally.

3.3.4

ABS SWITCHES/SENSORS

Master Cylinder: The master cylinder is a stan-

dard tandem compensating port design for ABS and
non ABS systems. Traction control vehicles use a
dual center port master cylinder. For proper trac-
tion control operation the standard master cylinder
must not be used.

A fluid level switch is located in the master

cylinder fluid reservoir. The switch closes when a
low fluid level is detected. The fluid level switch
turns on the brake warning indicator by grounding
the indicator circuit. This switch does not disable
the ABS system.

Wheel Speed Sensors and Tone Wheels: One

active wheel speed sensor (WSS) is located at each
wheel and sends a small DC signal to the control
module (CAB). This signal is generated when a
toothed sensor ring (tone wheel) passes by a station-
ary wheel speed sensor. The CAB converts the
signals for each wheel.

Because of internal circuitry, correct wheel speed

sensor function cannot be determined by a continu-
ity or resistance check through the sensor.

The front wheel speed sensor is attached to a boss

in the steering knuckle. The tone wheel is an
integral part of the front axle shaft. The rear speed
sensor is mounted though the bearing cover and the
rear tone wheel is an integral part of the rear
bearing hub. The wheel speed sensor air gap is not
adjustable. Refer to the service manual for wheel
speed sensor air gap and resistance specifications.

The four wheel speed sensors are serviced indi-

vidually. The front tone wheels are serviced as an
assembly with the outer constant velocity (C.V.)
joint housing. The rear tone wheels are serviced as
an assembly.

Correct antilock system operation is dependent

on tone wheel speed signals from the wheel speed
sensors. The vehicle’s wheels and tires should all be
the same size and type to generate accurate signals.
In addition, the tires should be inflated to the
recommended pressure for optimum system opera-
tion. Variation in wheel and tire size or significant
variations in inflation pressure can produce inaccu-
rate wheel speed signals; however, the system will
continue to function when using the correct factory
mini-spare.

3.3.5

ABS INITIALIZATION

System initialization starts when the key is

turned to “run”. At this point, the CAB performs a
complete self-check of all electrical components in
the antilock systems.

Between 8-17 km/h (5-10 mph), a dynamic test is

performed. This will momentarily cycle the inlet
and outlet valves, check wheel speed sensor cir-
cuitry, and run the pump motor at 25 km/h (15
mph). The CAB will try to test the pump motor. If
the brake pedal is applied the test will be run at 40
km/h (24 mph) regardless of brake switch state. If,
during the dynamic test, the brake pedal is applied,
the driver may feel the test through brake pedal
pulsations. This is a normal condition.

If any component exhibits a trouble condition

during system initialization or dynamic check, the
CAB will illuminate the ABS warning indicator and
TRAC OFF lamp if equipped.

3.3.6

ABS DIAGNOSTIC MODE

To enter diagnostic mode, a vehicle speed must be

below 10 km/h (6 mph) and no ABS condition
present. If vehicle speed is not below 10 km/h
(6 mph), a “No Response” message could be dis-
played by the DRBIII

t. The following are charac-

teristics of diagnostic mode:

– The amber ABS warning indicator will blink

rapidly. If a hard trouble code, such as Valve
Power Feed Failure code is present, the indi-
cator will be illuminated without blinking un-
til the trouble condition is cleared.

3

GENERAL INFORMATION

– Antilock operation is disabled.

– The HCU valves cannot be actuated when the

vehicle speed is above 8 km/h (5 mph). If valve
actuation is attempted above 8 km/h (5 mph), a
“No Response” message will be displayed on
the DRBIII

t.

3.3.7

TRACTION CONTROL OPERATION
(IF EQUIPPED)

The Controller Antilock Brake (CAB) monitors

wheel speeds. If, during acceleration, the module
detects front (drive) wheel slip and the brakes are
not applied, the CAB will enter traction control
mode. Traction control works in the following order
when drive wheel slip is detected.

1. Close the (normally open) isolation valves.

2. Start pump/motor and supply volume/pressure

to front hydraulic circuits (pump runs continu-
ously during traction control).

3. Open and close build and decay valves to main-

tain minimum wheel slip and maximum trac-
tion.

The cycling of the build and decay valves is

similar to the ABS except that they work to control
wheel spin by applying brakes. ABS function is to
control wheel skid by releasing brakes.

Two pressure relief valves allow excess fluid vol-

ume to return to the reservoir when not used by the
build/decay cycles. These are required because the
pump supplies more volume than the traction con-
trol system requires.

If at any time the brake pedal is applied during a

traction control cycle, the brake lamp switch will
trigger the CAB to switch off the traction control.

The traction control system will be enabled at

each ignition cycle. It may be turned off by depress-
ing the Traction Control Switch. The traction con-
trol system function lamp will illuminate “TRAC
OFF” immediately upon depressing the traction
control switch button. Only the “TRAC” portion of
the “TRAC OFF” indicator will illuminate during a
traction control event.

If the CAB calculates that the brake tempera-

tures are high, the traction control system will
become inoperative until a time-out period has
elapsed. When in this thermal protection mode, the
traction control “TRAC OFF” lamp will illuminate;
however, a fault will not be registered.

3.5

DIAGNOSTIC TROUBLE CODES

The Controller Antilock Brake may report any of

several Diagnostic Trouble Codes (DTC)s. For a list
of the DTCs diagnosed in this manual, refer to the
Table of Contents.

3.6

FREEZE FRAME

Freeze Frame takes a “snapshot” of specific vehi-

cle information the instant an ABS failure is recog-
nized and stores this information into the CAB
memory. This information can be accessed using the
DRBIII

t to help diagnose the fault. Freeze Frame

will capture the first time failure or only a new
failure that occurs during the current ignition cycle.

3.7

TIRE PRESSURE MONITORING
SYSTEM

If equipped with the Tire Pressure Monitoring

System, each of the vehicle’s four wheels will have a
valve stem with a pressure sensor and radio trans-
mitter built in. Signals from the tire pressure
Sensor/Transmitters are received and interpreted
by the Electronic Vehicle Information Center
(EVIC).

A Sensor/Transmitter in a mounted wheel will

broadcast its detected pressure once per minute when
the vehicle is moving faster than 32 km/h (20 mph).
Each Sensor/Transmitter’s broadcast is uniquely
coded so that the EVIC can determine location.

3.7.1

TRAINING THE EVIC

The EVIC can be trained to recognize the source

locations of Sensor/Transmitter signals. The train-
ing procedure is given below:

1. From the Programmable Features List select

“RETRAIN TIRE SENSORS Y/N” using the
EVIC MENU button.
Use the STEP button to select and the MENU
button to confirm “YES”. The EVIC will initiate
the following procedure.

2. A display will prompt the user to: “TRAIN

DRIVER FRONT SENSOR”. At this point the
user must set the left front tire Sensor/
Transmitter to learn mode by positioning a mag-
net (Relearn Magnet special tool 8821) over the
valve stem for at least 5 seconds. The Sensor/
Transmitter in the front left tire will transmit a
message indicating to the EVIC that it is in learn
mode. When the EVIC has received this message
and is assured that it has learned an ID, the
EVIC will request a horn chirp via a bus mes-
sage and then display the next train request.
Note: The EVIC will allow 60 seconds from
the first train request display to the receipt
of a unique learn ID message from the first
Sensor/Transmitter and 30 seconds for
each succeeding wheel. If either of these
timers expires, the EVIC will abort the
training procedure and revert to previous
settings. The EVIC will not store one ID for
multiple locations.

4

GENERAL INFORMATION