rear lamp CHRYSLER VOYAGER 2005 Owner's Manual

Vehicles with Fold-in-floor seating have three flex-
ible steel parking brake cables. They are:
²Front
²Left rear
²Right rear
The front parking brake cable extends from the
parking brake lever. A steel equalizer bracket con-
nects the front parking brake cable to the left rear
and intermediate cables on vehicles without Fold-in-
floor seating. The equalizer bracket connects the
front parking brake cable to the left rear and right
rear cables on vehicles with Fold-in-floor seating. The
intermediate cable is connected to the right rear
cable on vehicles without Fold-in-floor seating. A
standard cable connector is used to accomplish this
connection.
On vehicles equipped with rear drum brakes, the
rear service brakes also act as the vehicle's parking
brakes.
Vehicles equipped with rear disc brakes use a
small duo-servo brake assembly mounted to the each
rear disc brake caliper adapter as the parking brake.
The inside of the brake rotor (hat section of drum-in-
hat style brake rotor) is used as the parking brake
drum.
DESCRIPTION - EXPORT
The parking brake system on this vehicle features
a hand-operated parking brake lever. The lever is
located between the two front seats and requires a
special front cable.
OPERATION
The automatic-adjusting feature in the foot oper-
ated parking brake lever continuously applies mini-
mal tension to the parking brake cables when the
parking brake lever is in the released position to
keep them in adjustment at all times. Due to this
feature, the parking brake cables require no periodic
adjustment.
When the parking brake lever is applied, the
cables are pulled, thus applying the brake shoes
(rear drum brakes) or parking brake shoes (rear disc
brakes) at each rear wheel.
The brake shoes are mechanically operated by an
internal lever and strut connected to the rear park-
ing brake cables.
An equalizer bracket is used at the rear end of the
front parking brake cable to distribute tension
equally to each parking brake cable.
STANDARD PROCEDURE
STANDARD PROCEDURE - PARKING BRAKE
AUTOMATIC ADJUSTER TENSION RELEASE
The parking brake lever (pedal) mechanism used
in this vehicle is designed so that the automatic
adjuster is not required to be locked out when servic-
ing the parking brake lever (pedal) or the parking
brake cables.
This parking brake lever (pedal) mechanism is
designed so that the adjuster mechanism will rotate
only half a turn when the tension is released from
the parking brake cable. This eliminates the require-
ment to lock out the automatic adjuster when servic-
ing the parking brake lever (pedal) mechanism and
cables.
Use the following procedure to release the tension
from the parking brake cables and the automatic
adjuster in the parking brake lever (pedal) mecha-
nism.
(1) Release the parking brake.
(2) Raise and support the vehicle. (Refer to
LUBRICATION & MAINTENANCE/HOISTING -
STANDARD PROCEDURE)
(3) If equipped with Fold-in-floor seating, perform
the following:
(a) Clamp an appropriate pair of locking pliers
on the front parking brake cable strand approxi-
mately 25 mm (1 inch) forward of the button at the
equalizer (Fig. 95).
Fig. 95 Location To Grasp Cable At
RSBRAKES - BASE5-63
PARKING BRAKE (Continued)

(b) Grasp the equalizer and pull rearward on it
until enough slack is present to disconnect the
equalizer from front or rear cables. While holding
the front cable in this position using the locking
pliers, disconnect the equalizer from cables (Fig.
96).
(c) Ease up on the front cable tension allowing
the lever automatic self-adjusting mechanism to
pull the front cable strand forward. This action
allows the adjuster mechanism to rotate around to
its stop, removing tension from the adjuster and
front parking brake cable.
(d) Remove the locking pliers from the front
parking brake cable as necessary.
(4) If not equipped with Fold-in-floor seating, per-
form the following:
(a) Grasp the exposed section of the front park-
ing brake cable and pull rearward on it.
(b) While holding the cable in this position,
(c) Clamp an appropriate pair of locking pliers
on the front parking brake cable strand just rear-
ward of the second body outrigger bracket (Fig.
97).
(d) Disconnect the parking brake cables from the
parking brake cable equalizer (Fig. 98).
(e) Remove the locking pliers from the front
parking brake cable as necessary. This action
allows the adjuster mechanism to rotate around to
its stop, removing tension from the adjuster and
front parking brake cable.
STANDARD PROCEDURE - PARKING BRAKE
AUTOMATIC ADJUSTER TENSION RESET
NOTE: This procedure is designed for vehicles
without Fold-in-floor seating.
The parking brake lever (pedal) mechanism used
in this vehicle is designed so that the automatic
adjuster is not required to be locked out when servic-
ing the parking brake lever (pedal) or the parking
brake cables.
(1) Grasp the exposed section of the front parking
brake cable and pull rearward on it. While holding
Fig. 96 Parking Brake Cable Equalizer
1 - INTERMEDIATE BRACKET
2 - EQUALIZER
3 - LEFT REAR CABLE
4 - RIGHT REAR CABLE
5 - FRONT CABLE
Fig. 97 Locking Out Automatic Adjuster
1 - PARK BRAKE CABLE
2 - REAR BODY OUTRIGGER BRACKET
3 - LOCKING PLIERS
Fig. 98 Parking Brake Cable Attachment To
Equalizer
1 - EQUALIZER
2 - LEFT REAR PARKING BRAKE CABLE
3 - LOCKING NUT
4 - INTERMEDIATE PARKING BRAKE CABLE
5 - FRONT PARKING BRAKE CABLE
5 - 64 BRAKES - BASERS
PARKING BRAKE (Continued)

CABLE - PARKING BRAKE
FRONT
REMOVAL
REMOVAL
(1) Raise and support the vehicle. (Refer to
LUBRICATION & MAINTENANCE/HOISTING -
STANDARD PROCEDURE).
(2) Manually release the automatic self-adjusting
mechanism tension of the parking brake lever (pedal)
assembly. (Refer to 5 - BRAKES - STANDARD PRO-
CEDURE).
(3)
Remove the intermediate and left rear park brake
cable from the park brake cable equalizer (Fig. 100).
(4) Remove the front park cable housing retainer
from body outrigger bracket (Fig. 101). Cable is
removable by sliding a 14 mm box wrench over cable
retainer and compressing the three retaining fingers.
Alternate method is to use an aircraft type hose
clamp and screwdriver.
(5) Lower vehicle.
(6) Remove the left front door sill molding.
(7) Remove the left front kick panel for access to
the park brake cable and park brake pedal assembly.
(8) Lift floor mat for access to park brake cable
and floor pan. Pull the seal and the park brake cable
(Fig. 102) out of the floor pan of vehicle.
(9) Pull parking brake cable strand end forward
and disconnect button from clevis. Tap cable housing
end fitting out of pedal assembly bracket.
(10) Remove cable retainer from the parking brake
lever (pedal) assembly bracket.(11) Pull front parking brake cable assembly out of
vehicle through hole in floor pan.
REMOVAL - FOLD-IN-FLOOR SEATING
(1) Release the parking brake.
(2) Raise and support the vehicle. (Refer to
LUBRICATION & MAINTENANCE/HOISTING -
STANDARD PROCEDURE)
(3) Manually release the automatic self-adjusting
mechanism tension of the parking brake lever (pedal)
assembly. (Refer to 5 - BRAKES - STANDARD PRO-
CEDURE).
Fig. 100 Park Brake Cable Attachment To Equalizer
1 - EQUALIZER
2 - LEFT REAR PARKING BRAKE CABLE
3 - LOCKING NUT
4 - INTERMEDIATE PARKING BRAKE CABLE
5 - FRONT PARKING BRAKE CABLE
Fig. 101 Front Park Brake Cable Attachment To
Body
1 - CABLE HOUSING RETAINER
2 - BODY OUTRIGGER BRACKET
3 - PUSH WRENCH OVER END OF RETAINER HERE
4 - FRONT PARK BRAKE CABLE
Fig. 102 Front Park Brake Cable At Floor Pan
1 - PARK BRAKE PEDAL ASSEMBLY
2 - PARK BRAKE PEDAL
3 - CARPET
4 - FRONT PARK BRAKE CABLE
5 - SEAL
6 - FLOOR PAN
5 - 66 BRAKES - BASERS

CABLE - PARKING BRAKE
REAR
REMOVAL
REMOVAL - RIGHT REAR
(1) Raise and support the vehicle. (Refer to
LUBRICATION & MAINTENANCE/HOISTING -
STANDARD PROCEDURE).
(2) Remove rear tire and wheel assembly.
(3) Remove rear brake drum from the rear wheel
of the vehicle requiring service to the rear park
brake cable.
(4) Create slack in the rear parking brake cables
by locking out the automatic adjuster as described
here. Grasp an exposed section of front parking
brake cable near the equalizer and pull down on it.
At this time install a pair of locking pliers on the
cable just rearward of the second body outrigger
bracket (Fig. 110).(5) Disconnect the right rear parking brake cable
from the connector on the intermediate cable (Fig.
111).
(6) To remove the right parking brake cable hous-
ing from the body bracket, slide a 14 mm box end
wrench over the end of cable retainer to compress the
retaining fingers (Fig. 112). The alternate method
using an aircraft type hose clamp will not work on
the right side of the vehicle.
Fig. 110 Locking Out Automatic Adjuster
1 - PARK BRAKE CABLE
2 - REAR BODY OUTRIGGER BRACKET
3 - LOCKING PLIERS
Fig. 111 Right Rear Cable Connection To
Intermediate Cable
1 - RIGHT REAR PARKING BRAKE CABLE
2 - LOCKING NUT
3 - INTERMEDIATE PARKING BRAKE CABLE
Fig. 112 Right Park Brake Cable Removal From
Body Bracket
1 - RIGHT REAR BODY BRACKET
2 - PARK BRAKE CABLE
3 - 14MM WRENCH
4 - LEAF SPRING AND BRACKET
5 - 70 BRAKES - BASERS

(6) To remove parking brake cable housing from
the body bracket, slide a 14 mm box end wrench over
retainer end compressing the three fingers (Fig. 116).
Alternate method is to use an aircraft type hose
clamp.
(7) Remove the brake shoes from the brake sup-
port plate. (Refer to 5 - BRAKES/HYDRAULIC/ME-
CHANICAL/BRAKE PADS/SHOES - REMOVAL).
(8) Disconnect parking brake cable from parking
brake actuator lever.
(9) Remove the parking brake cable housing
retainer from the brake support plate using a 14mm
wrench to compress the retaining fingers (Fig. 117).
REMOVAL - FOLD-IN-FLOOR SEATING
(1) Release the parking brake.
(2) Raise and support the vehicle. (Refer to
LUBRICATION & MAINTENANCE/HOISTING -
STANDARD PROCEDURE)
(3) Manually release the automatic self-adjusting
mechanism tension of the parking brake lever (pedal)
assembly. (Refer to 5 - BRAKES - STANDARD PRO-
CEDURE)
(4) Remove the equalizer (Fig. 118).
(5) Remove the cable from the routing bracket fas-
tened to the underbody of the vehicle (Fig. 119).
(6) If the right rear cable is being serviced, remove
the screws fastening the cable routing clamps to the
rear axle (Fig. 120).
Fig. 116 Parking Brake Cable Removal From Body
Bracket
1 - LEFT REAR PARK BRAKE CABLE
2 - BODY BRACKET
3 - LEAF SPRING MOUNTING BRACKET
4 - CABLE RETAINER
5 - 14MM BOX WRENCH
Fig. 117 Removing Parking Brake Cable From Brake
Support Plate
1 - PARK BRAKE CABLE RETAINER
2 - PARK BRAKE CABLE
3 - 14MM BOX WRENCH
4 - BRAKE SUPPORT PLATE
Fig. 118 Parking Brake Cable Equalizer
1 - INTERMEDIATE BRACKET
2 - EQUALIZER
3 - LEFT REAR CABLE
4 - RIGHT REAR CABLE
5 - FRONT CABLE
5 - 72 BRAKES - BASERS
CABLE - PARKING BRAKE REAR (Continued)

Fig. 119 Left Rear Cable Routing
1 - ROUTING BRACKET
2 - LEFT REAR CABLE3 - RIGHT REAR CABLE
4 - SCREW
Fig. 120 Right Rear Cable Routing
1 - SCREWS
2 - ROUTING CLAMPS3 - REAR AXLE
RSBRAKES - BASE5-73
CABLE - PARKING BRAKE REAR (Continued)

INSTALLATION - LEFT REAR
(1) Install the rear parking brake cable in the
brake support plate. Insert cable housing retainer
into brake support plate making certain that cable
housing retainer fingers lock the housing and
retainer firmly into place.
(2) Attach the parking brake cable onto the park
brake actuator lever.
(3) Install the brake shoes on the rear brake sup-
port plate. (Refer to 5 - BRAKES/HYDRAULIC/ME-
CHANICAL/BRAKE PADS/SHOES -
INSTALLATION).
(4) Insert cable housing retainer into body outrig-
ger bracket making certain that cable housing
retainer fingers lock the housing firmly into place.
(5) Connect rear parking brake cable to the equal-
izer bracket (Fig. 115).
(6) Install brake drum, and wheel and tire assem-
bly.
(7) Remove the locking pliers from the front park
brake cable. This will automatically adjust the park
brake cables.
(8) Apply and release park brake pedal 1 time.
This will seat the park brake cables.
INSTALLATION - FOLD-IN-FLOOR SEATING
(1) Pass the leading end of the rear parking brake
cable through the hole in the end of the intermediate
bracket (Fig. 123). Press the cable housing retainer
through the hole until the fingers on the retainer
lock it into place.
(2) Route the cable back toward the brake assem-
bly placing it in the routing clip fastened to the
underbody of the vehicle (Fig. 119). Make sure to
stay to the inside of the left stabilizer bar link while
routing either cable.
(3) If the right rear cable is being serviced, install
screws, attaching the cable routing clamps to the
rear axle (Fig. 120).
(4) Pass the cable through the hole in the brake
adapter and hook the cable eyelet to the shoe lever
(Fig. 121).
(5) Install the screw fastening the cable to the rear
brake adapter (Fig. 121).
(6) Pull straight back on the front cable button
(and pliers) and properly attach the equalizer to all
three parking brake cables (Fig. 118).
(7) Remove the locking pliers from the front park-
ing brake cable and allow the automatic self-adjust-
ing mechanism in the lever to take up any slack.
(8) Lower the vehicle.
(9) Apply and release park brake pedal 1 time.
This will seat the parking brake cables.
LEVER - PARKING BRAKE
REMOVAL
(1) Manually release the automatic self-adjusting
mechanism tension of the parking brake lever (pedal)
assembly. (Refer to 5 - BRAKES/PARKING BRAKE -
STANDARD PROCEDURE).
(2) Disconnect negative (ground) cable from the
battery and isolate cable from battery terminal.
(3) Remove sill scuff plate from left door sill.
(4) Remove the left side kick panel.
(5) Remove the steering column cover from the
lower instrument panel.
(6) Remove the reinforcement from the lower
instrument panel.
(7) Remove the three bolts mounting the wiring
junction block to the instrument panel.
NOTE: When removing the lower mounting bolt,
push the park brake pedal down 5 clicks to access
the lower mounting bolt.
(8) Remove the lower bolt mounting the parking
brake lever (pedal) to the body (Fig. 124).
(9) Remove the forward nut mounting the parking
brake lever to the body (Fig. 124).
(10) Remove the upper bolt mounting the parking
brake lever to the body (Fig. 124).
(11) Pull downward on front parking brake cable
while rotating lever assembly out from behind junc-
tion block.
(12) Remove the release link from the parking
brake lever assembly.
(13) Disconnect the wiring connector from the indi-
cator lamp ground switch (Fig. 124) (Fig. 125).
Fig. 124 Parking Brake Lever Mounting
1 - WIRE HARNESS CONNECTOR
2 - LEVER MECHANISM
3 - FRONT CABLE
RSBRAKES - BASE5-75
CABLE - PARKING BRAKE REAR (Continued)

LEVER - PARKING BRAKE
(EXPORT)
REMOVAL - PARKING BRAKE LEVER AND
FRONT CABLE
(1) Raise vehicle. (Refer to LUBRICATION &
MAINTENANCE/HOISTING - STANDARD PROCE-
DURE)
(2) Grasp the exposed section of the front parking
brake cable and pull rearward on it. While holding
the park brake in this position, install a pair of lock-
ing pliers on the front parking brake cable just rear-
ward of the second body outrigger bracket (Fig. 126).
(3) Remove the left rear and intermediate parking
brake cables from the parking brake cable equalizer
(Fig. 127).
(4) Remove the equalizer from the front parking
brake cable.
(5) Remove the locking pliers from the front park-
ing brake cable. This will allow the adjuster in the
parking brake lever mechanism to rotate around to
its stop and remove the tension from the adjuster
and front park brake cable.
(6) Remove the front parking brake cable housing
from body outrigger bracket. Cable is removable by
sliding a 14 mm box wrench over the cable retainer
and compressing the three retaining fingers.Alter-
nate method:Use an aircraft type hose clamp and
screwdriver.
(7) Remove the four mounting nuts from the bot-
tom of the parking brake lever bracket.
(8) Lower vehicle.
(9) Remove the floor console. (Refer to 23 - BODY/
INTERIOR/FLOOR CONSOLE - REMOVAL)(10) If equipped with a manual transaxle, remove
the gearshift mechanism. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/MANUAL/SHIFT MECHANISM
- REMOVAL)
(11) Unhook the end of the parking brake cable
from the lever mechanism.
(12) Compress the parking brake cable retainer by
sliding a 14 mm wrench over the cable retainer and
compress the three (3) retaining fingers.
(13) Remove the three screws from the parking
brake grommet on the floor pan of the passenger
compartment.
(14) Lift the parking brake lever and slide the
parking brake cable out.
(15) Pull the cable through the floor pan from
inside the vehicle.
INSTALLATION - PARKING BRAKE LEVER AND
FRONT CABLE
(1) Pass the parking brake cable down through the
hole in the floor pan from inside of vehicle.
(2) Pass cable end button through the hole in the
lever bracket and press the cable housing into the
hole until all three retaining fingers lock the cable to
the lever bracket.
(3) Hook the end of the parking brake cable on the
parking brake lever mechanism.
(4) Press the cable grommet into the hole in the
floor pan and install the three screws securing it to
the floor pan.
(5) If equipped with a manual transaxle, install
the gearshift mechanism. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/MANUAL/SHIFT MECHANISM
- INSTALLATION)
Fig. 126 Locking Out Automatic Adjuster
1 - PARK BRAKE CABLE
2 - REAR BODY OUTRIGGER BRACKET
3 - LOCKING PLIERS
Fig. 127 Parking Brake Cable Equalizer
1 - EQUALIZER
2 - LEFT REAR PARKING BRAKE CABLE
3 - LOCKING NUT
4 - INTERMEDIATE PARKING BRAKE CABLE
5 - FRONT PARKING BRAKE CABLE
RSBRAKES - BASE5-77

DESCRIPTION - ELECTRONIC VARIABLE
BRAKE PROPORTIONING
Vehicles equipped with ABS use electronic variable
brake proportioning (EVBP) to balance front-to-rear
braking. The EVBP is used in place of a rear propor-
tioning valve. The EVBP system uses the ABS system
to control the slip of the rear wheels in partial brak-
ing 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 (ICU).
EVBP activation is invisible to the customer since
there is no pump motor noise or brake pedal feedback.
DESCRIPTION - TRACTION CONTROL SYSTEM
Traction control reduces wheel slip and maintains
traction at the driving wheels at speeds below 56
km/h (35 mph) when road surfaces are slippery. The
traction control system reduces wheel slip by braking
the wheel that is losing traction.
HYDRAULIC SHUTTLE VALVES
Two pressure relief hydraulic shuttle valves are
included on vehicles with traction control. These
valves are located inside the HCU and cannot be ser-
viced separately from the HCU.
TRACTION CONTROL LAMP
The traction control function lamp is located in the
transmission range indicator display of the instru-
ment cluster, displaying TRAC, TRAC OFF or nei-
ther depending on system mode.
The TRAC OFF lamp is controlled by a Traction
Control Off switch that is a momentary contact type
switch. The Traction Control Off switch is located on
the steering column upper shroud.
OPERATION
OPERATION - ANTILOCK BRAKE SYSTEM
There are a few performance characteristics of the
Mark 20e Antilock Brake System that may at first
seem abnormal, but in fact are normal. These char-
acteristics are described below.
NORMAL BRAKING
Under normal braking conditions, the ABS func-
tions the same as a standard base brake system with
a diagonally split master cylinder and conventional
vacuum assist.
ABS BRAKING
ABS operation is available at all vehicle speeds above
3±5 mph. If a wheel locking tendency is detected during
a brake application, the brake system enters the ABS
mode. During ABS braking, hydraulic pressure in thefour wheel circuits is modulated to prevent any wheel
from locking. Each wheel circuit is designed with a set of
electric solenoids to allow modulation, although for vehi-
cle stability, both rear wheel solenoids receive the same
electrical signal. Wheel lockup may be perceived at the
very end of an ABS stop and is considered normal.
During an ABS stop, the brakes hydraulic system
is still diagonally split. However, the brake system
pressure is further split into three control channels.
During antilock operation of the vehicle's brake sys-
tem, the front wheels are controlled independently
and are on two separate control channels, and the
rear wheels of the vehicle are controlled together.
The system can build and release pressure at each
wheel, depending on signals generated by the wheel
speed sensors (WSS) at each wheel and received at
the controller antilock brake (CAB).
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 surface 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.
5 - 88 BRAKES - ABSRS
BRAKES - ABS (Continued)

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 - ABS5-89
BRAKES - ABS (Continued)