ignition CHRYSLER VOYAGER 2002 Service Manual

GROUP TAB LOCATOR
INIntroduction
0Lubrication & Maintenance
2Suspension
3Differential & Driveline
5Brakes
6Clutch
7Cooling
7aCooling - 2.5L Turbo Diesel
8AAudio
8BChime/Buzzer
8EElectronic Control Modules
8EaElectronic Control Modules
8FEngine Systems
8FaEngine Systems
8GHeated Systems
8HHorn
8IIgnition Control
8IaIgnition Control
8JInstrument Cluster
8LLamps
8MMessage Systems
8NPower Systems
8ORestraints
8PSpeed Control
8QVehicle Theft Security
8RWipers/Washers
8WWiring
9Engine
9aEngine
11Exhaust System
11aExhaust System and Turbocharger
13Frame & Bumpers
14Fuel System
14aFuel System
19Steering
21Transmission
22Tires/Wheels
23Body
24Heating & Air Conditioning
25Emissions Control
25aEmissions Control 2.5L Turbo Diesel
Service Manual Comment Forms
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Light spark knock at low engine speeds is not
harmful to your engine. However, continued heavy
spark knock at high speeds can cause damage and
immediate service is required. Engine damage result-
ing from operation with a heavy spark knock may
not be covered by the new vehicle warranty.
Poor quality gasoline can cause problems such as
hard starting, stalling and hesitations. If you experi-
ence these symptoms, try another brand of gasoline
before considering service for the vehicle.
Over 40 auto manufacturers world-wide have
issued and endorsed consistent gasoline specifications
(the Worldwide Fuel Charter, WWFC) to define fuel
properties necessary to deliver enhanced emissions,
performance and durability for your vehicle. We rec-
ommend the use of gasolines that meet the WWFC
specifications if they are available.
REFORMULATED GASOLINE
Many areas of the country require the use of
cleaner burning gasoline referred to as ªreformulat-
edº gasoline. Reformulated gasoline contain oxygen-
ates, and are specifically blended to reduce vehicle
emissions and improve air quality.
We strongly support the use of reformulated gaso-
line. Properly blended reformulated gasoline will pro-
vide excellent performance and durability for the
engine and fuel system components.
GASOLINE/OXYGENATE BLENDS
Some fuel suppliers blend unleaded gasoline with
oxygenates such as 10% ethanol, MTBE, and ETBE.
Oxygenates are required in some areas of the country
during the winter months to reduce carbon monoxide
emissions. Fuels blended with these oxygenates may
be used in your vehicle.
CAUTION: DO NOT use gasoline containing METH-
ANOL. Gasoline containing methanol may damage
critical fuel system components.
MMT IN GASOLINE
MMT is a manganese-containing metallic additive
that is blended into some gasoline to increase octane.
Gasoline blended with MMT provide no performance
advantage beyond gasoline of the same octane num-
ber without MMT. Gasoline blended with MMT
reduce spark plug life and reduce emission system
performance in some vehicles. We recommend that
gasoline free of MMT be used in your vehicle. The
MMT content of gasoline may not be indicated on the
gasoline pump; therefore, you should ask your gaso-
line retailer whether or not his/her gasoline contains
MMT.
It is even more important to look for gasoline with-
out MMT in Canada because MMT can be used atlevels higher than allowed in the United States.
MMT is prohibited in Federal and California refor-
mulated gasoline.
SULFUR IN GASOLINE
If you live in the northeast United States, your
vehicle may have been designed to meet California
low emission standards with Cleaner-Burning Cali-
fornia reformulated gasoline with low sulfur. If such
fuels are not available in states adopting California
emission standards, your vehicles will operate satis-
factorily on fuels meeting federal specifications, but
emission control system performance may be
adversely affected. Gasoline sold outside of California
is permitted to have higher sulfur levels which may
affect the performance of the vehicle's catalytic con-
verter. This may cause the Malfunction Indicator
Lamp (MIL), Check Engine or Service Engine Soon
light to illuminate. We recommend that you try a dif-
ferent brand of unleaded gasoline having lower sulfur
to determine if the problem is fuel related prior to
returning your vehicle to an authorized dealer for
service.
CAUTION: If the Malfunction Indicator Lamp (MIL),
Check Engine or Service Engine Soon light is flash-
ing, immediate service is required; see on-board
diagnostics system section.
MATERIALS ADDED TO FUEL
All gasoline sold in the United States and Canada
are required to contain effective detergent additives.
Use of additional detergents or other additives is not
needed under normal conditions.
FUEL SYSTEM CAUTIONS
CAUTION: Follow these guidelines to maintain your
vehicle's performance:
²The use of leaded gas is prohibited by Federal
law. Using leaded gasoline can impair engine perfor-
mance, damage the emission control system, and
could result in loss of warranty coverage.
²An out-of-tune engine, or certain fuel or ignition
malfunctions, can cause the catalytic converter to
overheat. If you notice a pungent burning odor or
some light smoke, your engine may be out of tune or
malfunctioning and may require immediate service.
Contact your dealer for service assistance.
²When pulling a heavy load or driving a fully
loaded vehicle when the humidity is low and the tem-
perature is high, use a premium unleaded fuel to
help prevent spark knock. If spark knock persists,
lighten the load, or engine piston damage may result.
RSLUBRICATION & MAINTENANCE0-5
FLUID TYPES (Continued)
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(2) When using another vehicle as a booster
source, park the booster vehicle within cable reach.
Turn off all accessories, set the parking brake, place
the automatic transmission in PARK or the manual
transmission in NEUTRAL and turn the ignition
OFF.
(3) On disabled vehicle, place gear selector in park
or neutral and set park brake. Turn off all accesso-
ries.
(4) Connect jumper cables to booster battery. RED
clamp to positive terminal (+). BLACK clamp to neg-
ative terminal (-). DO NOT allow clamps at opposite
end of cables to touch, electrical arc will result.
Review all warnings in this procedure.
(5) On disabled vehicle, connect RED jumper cable
clamp to positive (+) terminal. Connect BLACK
jumper cable clamp to engine ground as close to the
ground cable attaching point as possible (Fig. 6).
(Refer to 8 - ELECTRICAL/BATTERY SYSTEM/BAT-
TERY - STANDARD PROCEDURE).
(6) Start the engine in the vehicle which has the
booster battery, let the engine idle a few minutes,
then start the engine in the vehicle with the dis-
charged battery.
CAUTION: Do not crank starter motor on disabled
vehicle for more than 15 seconds, starter may over-
heat and could fail.
(7) If engine does not start within 15 seconds, stop
cranking engine and allow starter to cool (15 min-
utes), before cranking again.DISCONNECT CABLE CLAMPS AS FOLLOWS:
²Disconnect BLACK cable clamp from engine
ground on disabled vehicle.
²When using a Booster vehicle, disconnect
BLACK cable clamp from battery negative terminal.
Disconnect RED cable clamp from battery positive
terminal.
²Disconnect RED cable clamp from battery posi-
tive terminal on disabled vehicle.
TOWING
STANDARD PROCEDURE - TOWING
WARNINGS AND CAUTIONS
WARNING: DO NOT ALLOW TOWING ATTACHMENT
DEVICES TO CONTACT THE FUEL TANK OR LINES,
FUEL LEAK CAN RESULT.
DO NOT LIFT OR TOW VEHICLE BY FRONT OR
REAR BUMPER.
DO NOT GO UNDER A LIFTED VEHICLE IF NOT
SUPPORTED PROPERLY ON SAFETY STANDS.
DO NOT ALLOW PASSENGERS TO RIDE IN A
TOWED VEHICLE.
USE A SAFETY CHAIN THAT IS INDEPENDENT
FROM THE TOWING ATTACHMENT DEVICE.
CAUTION: Do not damage brake lines, exhaust sys-
tem, shock absorbers, sway bars, or any other
under vehicle components when attaching towing
device to vehicle.
Do not secure vehicle to towing device by the use
of front or rear suspension or steering components.
Remove or secure loose or protruding objects from
a damaged vehicle before towing.
Refer to state and local rules and regulations before
towing a vehicle.
Do not allow weight of towed vehicle to bear on
lower fascia, air dams, or spoilers.
RECOMMENDED TOWING EQUIPMENT
To avoid damage to bumper fascia and air dams
use:
²FWD vehicles, use of a flat bed towing device or
a wheel lift is recommended (Fig. 7).
²AWD vehicles, a flat bed towing device or a
wheel lift and towing dolly is recommended (Fig. 7).
When using a wheel lift towing device, be sure the
disabled vehicle has at least 100 mm (4 in.) ground
clearance. If minimum ground clearance cannot be
reached, use a towing dolly. If a flat bed device is
used, the approach angle should not exceed 15
degrees.
Fig. 6 JUMPER CABLE CLAMP CONNECTIONS
1 - BATTERY NEGATIVE TERMINAL
2 - POSITIVE JUMPER CABLE
3 - TEST INDICATOR (IF EQUIPPED)
4 - BATTERY POSITIVE TERMINAL
5 - BATTERY
6 - NEGATIVE JUMPER CABLE
0 - 8 LUBRICATION & MAINTENANCERS
JUMP STARTING (Continued)
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(9) Depress retainers on rear of adjustable pedal
switch, then remove switch from lower shroud (Fig.
9).
INSTALLATION
(1) Guide adjustable pedal switch wiring through
mounting hole in lower shroud.
(2) Align switch retainers with notches in mount-
ing hole and snap the switch into place (Fig. 9).
(3) Connect adjustable pedal switch wiring connec-
tor along left side of column (Fig. 8).(4) Install the lower shroud with adjustable pedal
switch. Install screws fastening steering column
shrouds to steering column (Fig. 7).
(5) Install knee blocker reinforcement plate (Fig.
6).
(6) Connect parking brake release link to release
handle.
(7) Install data link diagnostic connector to mount-
ing hole in reinforcement plate.
(8) Install lower steering column cover/knee
blocker (Fig. 6).
(9) Install silencer panel below lower steering col-
umn cover/knee blocker.
(10) Connect ground cable to negative post of bat-
tery.
(11) Connect scan tool (DRBIIIt) to data link diag-
nostic connector located below steering column.
(12) Turn ignition key to ON position.
(13) Using scan tool, check for and clear any exist-
ing adjustable pedal fault codes.
(14) Test operation of adjustable pedals, memory
sets and RKE (if equipped). If applicable, reset radio
and clock.
(15) Recheck for any fault codes.
(16) Turn key to OFF and remove scan tool from
vehicle.
PEDAL POSITION SENSOR
DESCRIPTION
The pedal position sensor is part of the adjustable
pedal assembly. It is mounted to the left of the brake
pedal (Fig. 10). It senses the fore and aft position of
the brake pedal.
Fig. 7 Steering Column Shrouds
1 - FIXED SHROUD
2 - UPPER SHROUD
3 - CLOCKSPRING
4 - LOWER SHROUD
5 - STEERING COLUMN
Fig. 8 Pedal Switch Wiring Connector
1 - STEERING COLUMN FIXED SHROUD
2 - BRAKE TRANSMISSION SHIFT INTERLOCK
3 - B.T.S.I. WIRING CONNECTOR
4 - PEDAL SWITCH WIRING CONNECTOR
Fig. 9 Pedal Switch Retainers
1 - LOWER SHROUD INTERIOR
2 - RETAINERS
5 - 12 BRAKES - BASERS
ADJUSTABLE PEDAL SWITCH (Continued)
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DIAGNOSIS AND TESTING - PEDAL POSITION
SENSOR
Refer to Appropriate Diagnostic Information.
REMOVAL
(1) Remove battery ground cable terminal from
battery negative post and isolate.
(2) Under instrument panel, remove silencer panel
below lower steering column cover.
(3) Press release tab to the left (Fig. 11), then
remove bulkhead connector from bracket by pulling it
toward lower steering column cover.(4) Move bulkhead connector toward left side of
vehicle as far as its wires will allow. Do not over-
stress wiring.
(5) Remove two mounting screws securing pedal
position sensor in place (Fig. 12).
(6) Remove pedal position sensor from bracket.
(7) Disconnect wiring connector and remove pedal
position sensor.
INSTALLATION
(1) Connect wiring connector to pedal position sen-
sor.
NOTE: Make sure pin in pedal assembly fits into
slot in sensor carriage when installing sensor.
(2) Place sensor against mounting bracket and into
brake pedal (Fig. 12). Move carriage as necessary to
align slot with pin. Install two mounting screws.
Tighten screws to 7.5 N´m (66 in. lbs.) torque.
(3) Align the bulkhead connector mounting slot
with its bracket and install it, locking it in place.
(4) Install silencer panel below lower steering col-
umn cover.
(5) Connect ground cable to negative post of bat-
tery.
(6) Connect scan tool (DRBIIIt) to data link diag-
nostic connector located below steering column.
(7) Turn ignition key to ON position.
(8) Using scan tool, check for and clear any exist-
ing adjustable pedal fault codes.
(9) Test operation of adjustable pedals, memory
sets (if equipped), and RKE (if equipped). If applica-
ble, reset radio and clock.
(10) Recheck for any fault codes.
Fig. 10 Pedal Position Sensor Location
1 - PEDAL POSITION SENSOR
2 - BRAKE PEDAL
Fig. 11 Bulkhead Connector Release Tab
1 - RELEASE TAB
2 - PEDAL POSITION SENSOR
3 - BULKHEAD CONNECTOR
Fig. 12 Pedal Position Sensor
1 - WIRING CONNECTOR
2 - GEAR BOX
3 - PEDAL POSITION SENSOR
RSBRAKES - BASE5-13
PEDAL POSITION SENSOR (Continued)
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ing pedal adjustment, the APM will monitor pedal
position sensor voltage. If the APM does not detect
expected voltage change within 3 seconds, it will cut
power to the adjustable pedal motor.
An optional memory feature is available. This
allows storing of one or two preferred pedal positions
in the APS. A preferred position can be stored and
recalled using the door-mounted switches. A stored
pedal position can be recalled (but not stored) using
the Remote Keyless Entry (RKE) if equipped with
the memory feature.
DIAGNOSIS AND TESTING - ADJUSTABLE
PEDAL SYSTEM
Refer to Appropriate Diagnostic Information.
REMOVAL
NOTE: Before proceeding, review all Steering Col-
umn and Airbag Warnings and Cautions. (Refer to
19 - STEERING/COLUMN - WARNING)(Refer to 8 -
ELECTRICAL/RESTRAINTS - WARNING)
(1) Remove battery ground cable terminal from
battery negative post and isolate.
(2) Under instrument panel, remove silencer panel
below lower steering column cover.
(3) Remove screws securing lower steering column
cover/knee blocker, then remove it (Fig. 62).(4) Disconnect parking brake release link at
release handle.
(5) Compress tabs on sides of data link diagnostic
connector and remove it from knee blocker reinforce-
ment plate.
(6) Remove screws securing knee blocker reinforce-
ment plate in place, then remove reinforcement plate
(Fig. 62).
(7) Remove screws securing instrument panel
lower left reinforcement in place, then remove rein-
forcement (Fig. 63).
(8) Remove brake lamp switch. Discard the origi-
nal switch; it must not be reused (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/BRAKE
LAMP SWITCH - REMOVAL)
(9) Remove screws fastening upper and lower
steering column shrouds to steering column (Fig. 64).
(10) Remove the lower shroud with adjustable
pedal switch; disconnect switch wiring connector
along left side of column as shroud is removed (Fig.
65).
(11) Disconnect traction control off switch wiring
connector; Remove upper shroud with traction con-
trol off switch.
(12) Disconnect wiring harness connectors (as
equipped) from clockspring, multi-function switch,
halo lamp, SKIM module, ignition switch and BTSI
solenoid (Fig. 65).
(13) Disconnect column wiring harness routing clip
from column.
Fig. 62 Lower Steering Column Cover And
Reinforcement
1 - INSTRUMENT PANEL
2 - REINFORCEMENT PLATE
3 - LOWER STEERING COLUMN COVER/KNEE BLOCKER
Fig. 63 Instrument Panel Lower Left Reinforcement
1 - INSTRUMENT PANEL LOWER REINFORCEMENT
2 - STEERING WHEEL
3 - LOWER LEFT REINFORCEMENT
RSBRAKES - BASE5-43
PEDAL - ADJUSTABLE (Continued)
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(4) Tighten four booster mounting nuts and two
pedal bracket upper mounting bolts to 28 N´m (21 ft.
lbs.) torque.
(5) Install accelerator cable to pedal; install cable
retainer at accelerator pedal.
(6) Install booster input rod on brake pedal pin
and install a NEW retaining clip (Fig. 72).
(7) Install wiring harness in clips along pedal
bracket, then connect harness to pedal wiring har-
ness connector (Fig. 69).
(8) Install brake lamp switch bracket on pedal
assembly (Fig. 69). Tighten mounting nuts to 6 N´m
(50 in. lbs.) torque.(9) Install dash seal silencer shell over steering
column intermediate shaft and fasten in place (Fig.
68).
(10) Install the steering column on the mounting
studs. Install the two upper and two lower mounting
nuts. Tighten the upper, then lower mounting nuts to
12 N´m (105 in. lbs.) torque.
(11) Install the column shaft coupling onto the
intermediate shaft and install the pinch bolt (steer-
ing column should still be locked position it was
placed in during removal). Make sure the rounded
side of the intermediate shaft is matched to the cur-
vature of the coupling. Tighten the pinch bolt to 28
N´m (250 in. lbs.).
(12) Attach shift cable housing to bracket on col-
umn.
(13) Connect shift cable end to shift lever mecha-
nism pin (Fig. 66).
(14) Connect PRNDL cable to end of shift lever
mechanism pin and column bracket (Fig. 66).
(15) Connect column wiring harness connectors to
SKIM (if equipped), BTSI solenoid, ignition switch,
halo lamp, multi-function switch, and clockspring.
(16) Install the upper shroud (Refer to 19 -
STEERING/COLUMN/LOWER SHROUD - INSTAL-
LATION).
(17) If equipped, connect traction control off switch
wiring connector.
(18) Install upper shroud (with traction control off
switch if equipped) (Fig. 64).
(19) Connect adjustable pedal switch wiring con-
nector along left side of column (Fig. 65).
(20) Install the lower shroud with adjustable pedal
switch. Install screws fastening steering column
shrouds to steering column (Fig. 64).
CAUTION: Do not reuse the original brake lamp
switch. The switch can only be adjusted once. That
is during initial installation of the switch. If the
switch is not adjusted properly or has been
removed for some service, a new switch must be
installed and adjusted.
(21) Install and adjust NEW brake lamp switch.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/BRAKE LAMP SWITCH - INSTALLA-
TION)
(22) Install instrument panel lower left reinforce-
ment (Fig. 63).
(23) Attach hood release to lower left reinforce-
ment.
(24) Install knee blocker reinforcement plate (Fig.
62).
(25) Connect parking brake release link to release
handle.
(26) Install data link diagnostic connector to
mounting hole in reinforcement plate.
Fig. 71 Booster Mounting (Typical)
1 - DASH BRACKET
2 - POWER BRAKE BOOSTER
3 - BRAKE PEDAL ASSEMBLY
Fig. 72 Retaining Pin Installed On Brake Pedal Pin
1 - BRAKE PEDAL
2 - RETAINING CLIP
3 - BOOSTER INPUT ROD
5 - 46 BRAKES - BASERS
PEDAL - ADJUSTABLE (Continued)
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(27) Install lower steering column cover/knee
blocker (Fig. 62).
(28) Install silencer panel below lower steering col-
umn cover/knee blocker.
NOTE: When reconnecting the battery on a vehicle
that has had the airbag module removed, the fol-
lowing procedure should be used.
(29) Reconnect ground cable to negative post of
battery in following manor:
(a) Connect scan tool (DRBIIIt) to data link
diagnostic connector located below steering column.
(b) Turn ignition key to ON position. Exit vehi-
cle with scan tool leaving scan tool harness
plugged in.
(c) Ensuring that there are no occupants in vehi-
cle, connect ground (-) cable to the negative post of
the battery.
(d) Using scan tool, read and record any airbag
fault codes. Refer to Appropriate Diagnostic Infor-
mation if any faults are found.
(e) Through drivers open window, Reach around
back of steering wheel (between steering wheel and
instrument cluster) and turn ignition key to OFF,
then back ON while observing instrument cluster
airbag indicator lamp. It should go on for six to
eight seconds, then go out. This action indicates
that airbag system is functioning normally. If air-
bag indicator lamp fails to light, blinks on and off,
or goes on and stays on, there is an airbag system
malfunction. Refer to Appropriate Diagnostic Infor-
mation to diagnose the system malfunction.
(30) Using scan tool (DRBIIIt), check for and clear
any existing adjustable pedal fault codes. The adjust-
able pedal system is now activated.
(31) Turn key to OFF and remove scan tool from
vehicle.
(32) Test operation of adjustable pedals, memory
seats (if equipped), RKE (if equipped), and all func-
tions that are steering column operated. If applica-
ble, reset the radio and the clock.
(33) Road test the vehicle to ensure proper opera-
tion of the steering and brake systems.
PEDAL TORQUE SHAFT - RHD
REMOVAL
(1) Remove the instrument panel. (Refer to 23 -
BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL ASSEMBLY - REMOVAL)
(2) Remove the HVAC housing. (Refer to 24 -
HEATING & AIR CONDITIONING/DISTRIBUTION/
HVAC HOUSING - REMOVAL)
(3) Remove the retaining clip at the torque shaft
end of the brake pedal-to-torque shaft link. Removethe link from the torque shaft. Discard the retaining
clip. It is not to be reused. Replace with a new clip
when reassembled.
(4) Locate the booster input rod-to-brake pedal
torque shaft connection and remove the retaining clip
(Fig. 73). Discard the retaining clip. It is not to be
reused. Replace with a new clip when reassembled.
(5) Remove the four (4) brake booster retaining
nuts from inside the passenger compartment (Fig.
74).
(6) Remove the retaining nut from the brake
booster bracket located above the booster in the
engine compartment (Fig. 74).
(7) Remove the power brake booster bracket.
(8) Rotate the pedal torque shaft and remove it out
the left side of the vehicle.
INSTALLATION
(1) Lubricate both ends of the torque shaft with
MS-4517 Lubricant or equivalent and install the
torque shaft from the left side reversing the removal
procedure.
(2) Install the brake booster bracket on the left
end of the shaft.
(3) Install the four brake booster retaining nuts
inside the passenger compartment. Tighten the
mounting nuts to a torque of 29 N´m (250 in. lbs.).
(4) Install the retaining nut for the brake booster
bracket in the engine compartment. Tighten the
mounting nuts to a torque of 29 N´m (250 in. lbs.).
(5) Using lubriplate, or equivalent, coat the sur-
face of the brake pedal torque shaft pin where it con-
tacts the booster input rod. Also coat the surface of
Fig. 73 POWER BRAKE BOOSTER BRACKET
1 - BOOSTER BRACKET
2 - PEDAL TORQUE SHAFT
3 - RETAINING CLIP
4 - BOOSTER MOUNTING NUTS
RSBRAKES - BASE5-47
PEDAL - ADJUSTABLE (Continued)
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black tire marks since the wheel never reaches a
fully locked condition. However, tire marks may be
noticeable as light patched marks.
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 thepressure 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 the
master 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
RSBRAKES - ABS5-87
BRAKES - ABS (Continued)
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ªthermo-protection mode,º the traction control func-
tion lamp illuminates TRAC OFF; note that no trou-
ble code is registered.
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.
5 - 88 BRAKES - ABSRS
BRAKES - ABS (Continued)
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