2004 CHRYSLER VOYAGER brake fluid

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.
OPERATION - ELECTRONIC VARIABLE BRAKE
PROPORTIONING
Upon entry into EVBP 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
the rear brake circuit is pulsed. This allows fluid to
enter the low pressure accumulator (LPA) in the
hydraulic control unit (HCU) resulting in a drop in
fluid pressure to the rear brakes. In order to increase
the rear brake pressure, the outlet valve is switched
off and the inlet valve is pulsed. This increases the
pressure to the rear brakes. This back-and-forth pro-
cess will continue until the required slip difference is
obtained. At the end of EVBP braking (brakes
released) the fluid in the LPA drains back to themaster cylinder by switching on the outlet valve and
draining through the inlet valve check valve. At the
same time the inlet valve is switched on in case of
another brake application.
The EVBP will remain functional during many
ABS fault modes. If both the red BRAKE and amber
ABS warning indicators are illuminated, the EVBP
may not be functioning.
OPERATION - TRACTION CONTROL SYSTEM
The traction control module monitors wheel speed.
During acceleration, if the module detects front
(drive) wheel slip and the brakes are not applied, the
module enters traction control mode. Traction control
operation proceeds in the following order:
(1) Close the normally open isolation valves.
(2) Start the pump/motor and supply volume and
pressure to the front (drive) hydraulic circuit. (The
pump/motor runs continuously during traction con-
trol operation.)
(3) Open and close the build and decay valves to
maintain minimum wheel slip and maximum trac-
tion.
The cycling of the build and decay valves during
traction control is similar to that during antilock
braking, except the valves work to control wheel spin
by applying the brakes, whereas the ABS function is
to control wheel skid by releasing the brakes.
If the brakes are applied at anytime during a trac-
tion control cycle, the brake lamp switch triggers the
controller to switch off traction control.
HYDRAULIC SHUTTLE VALVES
Two pressure relief hydraulic shuttle valves allow
pressure and volume to return to the master cylinder
reservoir when not consumed by the build and decay
valves. These valves are necessary because the
pump/motor supplies more volume than the system
requires.
TRACTION CONTROL LAMP
The traction control system is enabled at each igni-
tion cycle. It may be turned off by depressing the
Traction Control Off switch button when the ignition
is in the ON position. The traction control function
lamp (TRAC OFF) illuminates immediately upon
depressing the button.
The traction control function lamp illuminates dur-
ing a traction control cycle, displaying TRAC.
If the CAB calculates that the brake temperatures
are high, the traction control system becomes inoper-
ative until a time-out period has elapsed. During this
ªthermo-protection mode,º the traction control func-
tion lamp illuminates TRAC OFF; note that no trou-
ble code is registered.
RSBRAKES - ABS5-77
BRAKES - ABS (Continued)

CAUTION
CAUTIONS
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.
5 - 78 BRAKES - ABSRS
BRAKES - ABS (Continued)

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 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 YOURSELF
AND 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. (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 5 - BRAKES - BASE - SPECIFICA-
TIONS)
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 &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE)
(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
Fig. 1 Front Wheel Speed Sensor Attaching Bolt
1 - MOUNTING BOLT
2 - WHEEL SPEED SENSOR
3 - DRIVESHAFT
4 - TONE WHEEL
5 - STEERING KNUCKLE
RSBRAKES - ABS5-79
BRAKES - ABS (Continued)

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 - ABS5-83

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 - 84 BRAKES - ABSRS
HYDRAULIC/MECHANICAL (Continued)

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 - ABS5-85
HYDRAULIC/MECHANICAL (Continued)

ABS BRAKING HYDRAULIC CIRCUIT, SOLENOID
VALVE, AND SHUTTLE VALVE FUNCTION (ABS
WITH TRACTION CONTROL)
The hydraulic diagram (Fig. 10) 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 hydraulic shuttle valve closes upon brake
application so that the pump/motor cannot siphon
brake fluid from the master cylinder.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. 10 ABS With Traction Control - ABS Braking Hydraulic Circuit
1 - OUTLET VALVE
2 - PUMP PISTON
3 - PUMP MOTOR (ON)
4 - SUCTION VALVE
5 - LOW PRESSURE ACCUMULATOR
6 - NORMALLY CLOSED VALVE (MODULATING)
7 - TO RIGHT FRONT WHEEL
8 - NORMALLY OPEN VALVE (MODULATING)9 - NORMALLY OPEN ASR VALVE (OFF)
10 - FROM MASTER CYLINDER
11 - HYDRAULIC SHUTTLE VALVE
12 - MASTER CYLINDER PRESSURE
13 - CONTROLLED WHEEL PRESSURE
14 - LOW PRESSURE ACCUMULATOR PRESSURE
15 - PUMP INTERSTAGE PRESSURE
16 - NOISE DAMPER CHAMBER
RSBRAKES - ABS5-87
HYDRAULIC/MECHANICAL (Continued)

ABS TRACTION CONTROL HYDRAULIC CIRCUIT,
SOLENOID VALVE, AND SHUTTLE VALVE
FUNCTION (ABS WITH TRACTION CONTROL)
The hydraulic diagram (Fig. 11) shows the vehicle
in the ABS braking mode. The diagram shows a drive
wheel is spinning and brake pressure is required to
reduce its speed.²The normally open ASR valve is energized to iso-
late the brake fluid being pumped from the master
cylinder and to isolate the driven wheel.
²The normally open ASR valve bypasses the
pump output back to the master cylinder at a fixed
pressure setting.
²The normally open and normally closed valves
modulate (build/decay) the brake pressure as
required to the spinning wheel.
Fig. 11 Traction Control 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 WHEEL (SPINNING)
8 - NORMALLY OPEN VALVE (MODULATING)
9 - NORMALLY OPEN ASR VALVE ON (REGULATING)10 - FROM MASTER CYLINDER
11 - HYDRAULIC SHUTTLE VALVE
12 - CONTROLLED WHEEL PRESSURE
13 - SUCTION VALVE
14 - PUMP INTERSTAGE PRESSURE
15 - NOISE DAMPER CHAMBER
16 - MASTER CYLINDER PRESSURE
17 - PUMP PRESSURE
5 - 88 BRAKES - ABSRS
HYDRAULIC/MECHANICAL (Continued)