egr valve JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual

BRAKES - ABS
TABLE OF CONTENTS
page page
BRAKES - ABS
DESCRIPTION.........................41
OPERATION...........................41
DIAGNOSIS AND TESTING - ANTILOCK
BRAKES............................42
STANDARD PROCEDURE - BLEEDING ABS
BRAKE SYSTEM......................42
SPECIFICATIONS
TORQUE CHART......................42
ELECTRIC BRAKE
DESCRIPTION.........................43
OPERATION...........................43
FRONT WHEEL SPEED SENSOR
DESCRIPTION.........................43
OPERATION...........................43
REMOVAL.............................43INSTALLATION.........................43
G-SWITCH
DESCRIPTION.........................44
OPERATION...........................44
REMOVAL.............................44
INSTALLATION.........................44
REAR WHEEL SPEED SENSOR
DESCRIPTION.........................45
OPERATION...........................45
REMOVAL.............................45
INSTALLATION.........................46
HCU (HYDRAULIC CONTROL UNIT)
DESCRIPTION.........................46
OPERATION...........................46
REMOVAL.............................47
INSTALLATION.........................47
BRAKES - ABS
DESCRIPTION
The purpose of the antilock system is to prevent
wheel lockup during periods of high wheel slip. Pre-
venting lockup helps maintain vehicle braking action
and steering control.
The hydraulic system is a three channel design.
The front brakes are controlled individually and the
rear brakes in tandem.
The ABS electrical system is separate from other
vehicle electrical circuits. A separate controller oper-
ates the system.
OPERATION
The antilock CAB activates the system whenever
sensor signals indicate periods of high wheel slip.
High wheel slip can be described as the point where
wheel rotation begins approaching 20 to 30 percent of
actual vehicle speed during braking. Periods of high
wheel slip occur when brake stops involve high pedal
pressure and rate of vehicle deceleration.
Battery voltage is supplied to the CAB ignition ter-
minal when the ignition switch is turned to Run posi-
tion. The CAB performs a system initialization
procedure at this point. Initialization consists of a
static and dynamic self check of system electrical
components.
The static check occurs after the ignition switch is
turned to Run position. The dynamic check occurs
when vehicle road speed reaches approximately 30kph (18 mph). During the dynamic check, the CAB
briefly cycles the pump and solenoids to verify oper-
ation.
If an ABS component exhibits a fault during ini-
tialization, the CAB illuminates the amber warning
light and registers a fault code in the microprocessor
memory.
ANTILOCK BRAKING
The antilock system prevents lockup during high
slip conditions by modulating fluid apply pressure to
the wheel brake units.
Brake fluid apply pressure is modulated according
to wheel speed, degree of slip and rate of decelera-
tion. A sensor at each wheel converts wheel speed
into electrical signals. These signals are transmitted
to the CAB for processing and determination of
wheel slip and deceleration rate.
The ABS system has three fluid pressure control
channels. The front brakes are controlled separately
and the rear brakes in tandem. A speed sensor input
signal indicating a high slip condition activates the
CAB antilock program.
Two solenoid valves are used in each antilock con-
trol channel. The valves are all located within the
HCU valve body and work in pairs to either increase,
hold, or decrease apply pressure as needed in the
individual control channels.
The solenoid valves are not static during antilock
braking. They are cycled continuously to modulate
pressure. Solenoid cycle time in antilock mode can be
measured in milliseconds.
WJBRAKES - ABS 5 - 41

(1) Position sensor into the coolant recovery pres-
sure container (Fig. 1).
(2) Connect the coolant level sensor electrical con-
nector (Fig. 2).
(3) Close hood.
COOLANT RECOVERY PRESS
CONTAINER
DESCRIPTION
This system works along with the radiator pres-
sure cap. This is done by using thermal expansion
and contraction of the coolant to keep the coolant
free of trapped air. It provides:
²A volume for coolant expansion and contraction.
²A convenient and safe method for checking/ad-
justing coolant level at atmospheric pressure. This is
done without removing the radiator pressure cap.
²Some reserve coolant to the radiator to cover
minor leaks and evaporation or boiling losses.
As the engine cools, a vacuum is formed in the
cooling system of both the radiator and engine. Cool-
ant will then be drawn from the coolant tank and
returned to a proper level in the radiator.
The coolant reservoir/overflow system has a radia-
tor mounted pressurized cap, an overflow tube and a
plastic coolant reservoir/overflow tank (Fig. 3)
mounted to the right inner fender.
RADIATOR FAN - 4.7L
DESCRIPTION
The hydraulic fan (Fig. 4) used on vehicles
equipped the 4.7L engine, replaces both the electric
fan and the engine driven mechanical fan. The
hydraulic cooling fan is integral to the fan shroud
and is located between the radiator and the engine.
The power steering pump supplies the hydraulic
fluid and pressure to rotate the cooling fan blade,
while the electrical part of the fan is controlled by
the JTEC.
The hydraulic fan drive (motor) consists of the
three major following components:
²Steering flow control valve
Fig. 1 COOLANT LEVEL SENSOR ELECTRICAL
CONNECTOR
Fig. 2 COOLANT LEVEL SENSOR REMOVAL/
INSTALLATION
Fig. 3 Coolant Reservoir / Overflow Tank
1 - COOLANT OVERFLOW HOSE
2 - COOLANT RESERVOIR/OVERFLOW TANK
3 - COOLANT LEVEL SENSOR
4 - BOLT
WJENGINE 7 - 27
COOLANT LEVEL SENSOR (Continued)

DESCRIPTION - POWER GROUNDS
The Powertrain Control Module (PCM) has 2 main
grounds. Both of these grounds are referred to as
power grounds. All of the high-current, noisy, electri-
cal devices are connected to these grounds as well as
all of the sensor returns. The sensor return comes
into the sensor return circuit, passes through noise
suppression, and is then connected to the power
ground.
The power ground is used to control ground cir-
cuits for the following PCM loads:
²Generator field winding
²Fuel injectors
²Ignition coil(s)
²Certain relays/solenoids
²Certain sensors
DESCRIPTION - SENSOR RETURN
The Sensor Return circuits are internal to the Pow-
ertrain Control Module (PCM).
Sensor Return provides a low±noise ground refer-
ence for all engine control system sensors. Refer to
Power Grounds for more information.
OPERATION
OPERATION - PCM
(1) Also refer to Modes of Operation.
The PCM operates the fuel system. The PCM is a
pre-programmed, triple microprocessor digital com-
puter. It regulates ignition timing, air-fuel ratio,
emission control devices, charging system, certain
transmission features, speed control, air conditioning
compressor clutch engagement and idle speed. The
PCM can adapt its programming to meet changing
operating conditions.
The PCM receives input signals from various
switches and sensors. Based on these inputs, the
PCM regulates various engine and vehicle operations
through different system components. These compo-
nents are referred to as Powertrain Control Module
(PCM) Outputs. The sensors and switches that pro-
vide inputs to the PCM are considered Powertrain
Control Module (PCM) Inputs.
The PCM adjusts ignition timing based upon
inputs it receives from sensors that react to: engine
rpm, manifold absolute pressure, engine coolant tem-
perature, throttle position, transmission gear selec-
tion (automatic transmission), vehicle speed and the
brake switch.
The PCM adjusts idle speed based on inputs it
receives from sensors that react to: throttle position,
vehicle speed, transmission gear selection, engine
coolant temperature and from inputs it receives from
the air conditioning clutch switch and brake switch.Based on inputs that it receives, the PCM adjusts
ignition coil dwell. The PCM also adjusts the gener-
ator charge rate through control of the generator
field and provides speed control operation.
NOTE: PCM Inputs:
²A/C request
²Auto shutdown (ASD) sense
²Battery temperature
²Battery voltage
²Brake switch
²J1850 bus circuits
²Camshaft position sensor signal
²Crankshaft position sensor
²Data link connections for DRB scan tool
²Engine coolant temperature sensor
²Five volts (primary)
²Five volts (secondary)
²Fuel level
²Generator (battery voltage) output
²Ignition circuit sense (ignition switch in on/off/
crank/run position)
²Intake manifold air temperature sensor
²Leak detection pump (switch) sense (if equipped)
²Manifold absolute pressure (MAP) sensor
²Oil pressure
²Overdrive/override switch
²Oxygen sensors
²Park/neutral switch (auto. trans. only)
²Power ground
²Sensor return
²Signal ground
²Speed control multiplexed single wire input
²Throttle position sensor
²Transmission governor pressure sensor
²Transmission temperature sensor
²Vehicle speed (from ABS module)
NOTE: PCM Outputs:
²A/C clutch relay
²Auto shutdown (ASD) relay
²J1850 (+/-) circuits for: speedometer, voltmeter,
fuel gauge, oil pressure gauge/lamp, engine temp.
gauge and speed control warn. lamp
²Data link connection for DRBIIItscan tool
²EGR valve control solenoid (if equipped)
²EVAP canister purge solenoid
²Fuel injectors
²Fuel pump relay
²Generator field driver (-)
²Generator field driver (+)
²Generator lamp (if equipped)
²Idle air control (IAC) motor
²Ignition coil
²Leak detection pump
WJELECTRONIC CONTROL MODULES 8E - 15
POWERTRAIN CONTROL MODULE (Continued)

STANDARD PROCEDURE
STANDARD PROCEDURE - TCM QUICK LEARN
The quick learn procedure requires the use of the
DRBIIItscan tool.
This program allows the electronic transmission
system to recalibrate itself. This will provide the
proper transmission operation. The quick learn pro-
cedure should be performed if any of the following
procedures are performed:
²Transmission Assembly Replacement
²Transmission Control Module Replacement
²Solenoid Pack Replacement
²Clutch Plate and/or Seal Replacement
²Valve Body Replacement or ReconditionTo perform the Quick Learn Procedure, the follow-
ing conditions must be met:
²The brakes must be applied
²The engine speed must be above 500 rpm
²The throttle angle (TPS) must be less than 3
degrees
²The shift lever position must stay in PARK until
prompted to shift to overdrive
²The shift lever position must stay in overdrive
after the Shift to Overdrive prompt until the DRBt
indicates the procedure is complete
²The calculated oil temperature must be above
60É and below 200É
8E - 22 ELECTRONIC CONTROL MODULESWJ
TRANSMISSION CONTROL MODULE (Continued)

²Front Check Valve- The front washer system
check valve is integral to the wye fitting located in
the washer plumbing between the cowl plenum
washer hose and the front washer nozzles, and is
concealed beneath the cowl plenum cover/grille panel
at the base of the windshield.
²Front Washer Nozzle- Two fluidic front
washer nozzles are secured with integral snap fea-
tures to dedicated openings in the cowl plenum cover/
grille panel located near the base of the windshield.
²Front Washer Plumbing- The plumbing for
the front washer system consists of rubber hoses and
molded plastic fittings. The plumbing is routed along
the left side of the engine compartment from the
washer reservoir, and through the dash panel into
the cowl plenum to the front washer nozzle fittings
beneath the cowl plenum cover/grille panel.
²Front Washer Pump/Motor- The front washer
pump/motor unit is located in a dedicated hole on the
lower outboard side of the washer reservoir, behind
the inner fender liner ahead of the left front wheel.
The front washer pump is located ahead of and below
the rear washer pump.
²Front Wiper Arm- The two front wiper arms
are secured with nuts to the threaded studs on the
ends of the two wiper pivot shafts, which extend
through the cowl plenum cover/grille panel located
near the base of the windshield.
²Front Wiper Blade- The two front wiper
blades are secured to the two front wiper arms with
an integral latch, and are parked on the glass near
the bottom of the windshield when the front wiper
system is not in operation.
²Front Wiper Module- The front wiper pivot
shafts are the only visible components of the front
wiper module. The remainder of the module is con-
cealed within the cowl plenum beneath the cowl ple-
num cover/grille panel. The front wiper module
includes the module bracket, four rubber-isolated
wiper module mounts, the front wiper motor, the
wiper motor crank arm, the two wiper drive links,
and the two front wiper pivots.
²Rain Sensor Module- Models equipped with
the optional automatic wiper feature have a Rain
Sensor Module (RSM) located behind a trim cover on
a bracket bonded to the inside surface of the wind-
shield glass, just above the inside rear view mirror
mounting button.
²Right Multi-Function Switch- The right
(wiper) multi-function switch is secured to the right
side of the multi-function switch mounting housing
near the top of the steering column, just below the
steering wheel. Only the control stalk for the right
multi-function switch is visible, while the remainder
of the switch is concealed beneath the steering col-
umn shrouds. The right multi-function switch con-tains all of the switches and control circuitry for both
the front and rear wiper and washer systems.
²Washer Fluid Level Switch- The washer fluid
level switch is located in a dedicated hole near the
center of the forward surface of the washer reservoir,
behind the left front wheel house splash shield.
²Washer Reservoir- The washer reservoir is
concealed between the left inner fender shield and
the left outer fender panel, behind the inner fender
liner and ahead of the left front wheel. The washer
reservoir filler neck is the only visible portion of the
reservoir, and it is accessed from the left front corner
of the engine compartment.
²Wiper High-Low Relay- The wiper high-low
relay is an International Standards Organization
(ISO) micro relay located in the Power Distribution
Center (PDC) in the engine compartment near the
battery.
²Wiper On-Off Relay- The wiper on-off relay is
an International Standards Organization (ISO) micro
relay located in the Power Distribution Center (PDC)
in the engine compartment near the battery.
Hard wired circuitry connects the front wiper and
washer system components to the electrical system of
the vehicle. These hard wired circuits are integral to
several wire harnesses, which are routed throughout
the vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the front wiper and
washer system components through the use of a com-
bination of soldered splices, splice block connectors,
and many different types of wire harness terminal
connectors and insulators. Refer to the appropriate
wiring information. The wiring information includes
wiring diagrams, proper wire and connector repair
procedures, further details on wire harness routing
and retention, as well as pin-out and location views
for the various wire harness connectors, splices and
grounds.
OPERATING MODES
The components of the front wiper and washer sys-
tem are designed to work in concert to provide the
following operating modes:
²Automatic Wiper- In models equipped with
the optional automatic wiper feature, the internal
circuitry of both the right (wiper) multi-function
switch, the rain sensor module, and the BCM work
in concert to provide an automatic wiper mode with
five sensitivity selections. The BCM tells the Rain
Sensor Module (RSM) when the automatic wiper
mode is selected and the manually selected sensitiv-
ity level, then the rain sensor module tells the BCM
each time enough water droplets have accumulated
within the wipe pattern on the windshield to require
front wiper operation. The BCM then automatically
WJFRONT WIPERS/WASHERS 8R - 3
FRONT WIPERS/WASHERS (Continued)

WASHER SYSTEM
The washer system components should be
inspected periodically, not just when washer perfor-
mance problems are experienced. This inspection
should include the following points:
(1) Check for ice or other foreign material in the
washer reservoir. If contaminated, clean and flush
the washer system. (Refer to 8 - ELECTRICAL/
FRONT WIPERS/WASHERS - CLEANING).
(2) Inspect the washer plumbing for pinched, leak-
ing, deteriorated, or incorrectly routed hoses and
damaged or disconnected hose fittings. Replace dam-
aged or deteriorated hoses and hose fittings. Leaking
washer hoses can sometimes be repaired by cutting
the hose at the leak and splicing it back together
using an in-line connector fitting. Similarly, sections
of deteriorated hose can be cut out and replaced by
splicing in new sections of hose using in-line connec-
tor fittings. Whenever routing a washer hose or a
wire harness containing a washer hose, it must be
routed away from hot, sharp, or moving parts. Also,
sharp bends that might pinch the washer hose must
be avoided.
FRONT CHECK VALVE
DESCRIPTION
A front washer system check valve is standard
equipment on this model. The front check valve is
integral to the front washer nozzle plumbing wye fit-
ting located in the cowl plenum beneath the cowl ple-
num cover/grille panel near the base of the
windshield. The check valve consists of a molded
plastic body with a round center section. Three
barbed hose nipples are formed in a wye configura-
tion on the outside circumference of the center sec-
tion of the valve body. Within the check valve body, a
small check valve operated by a small coiled spring
restricts flow through the unit until the valve is
unseated by a predetermined inlet fluid pressure.
The front check valve cannot be adjusted or repaired
and, if faulty or damaged, it must be replaced.
OPERATION
The front check valve provides more than one func-
tion in this application. It serves as a wye connector
fitting between the cowl grille panel and washer noz-
zle sections of the front washer supply hose. It also
prevents washer fluid from draining out of the front
washer supply hoses back to the washer reservoir.
This drain-back would result in a lengthy delay from
when the front washer switch is actuated until
washer fluid was dispensed through the front washer
nozzles, because the front washer pump would have
to refill the front washer plumbing from the reservoir
to the nozzles. Finally, the front check valve prevents
washer fluid from siphoning through the front
washer nozzles after the front washer system is
turned Off. When the front washer pump pressurizes
and pumps washer fluid from the reservoir through
the front washer plumbing, the fluid pressure over-
rides the spring pressure applied to the check valve
and unseats the valve, allowing washer fluid to flow
toward the front washer nozzles. When the front
washer pump stops operating, spring pressure seats
the check valve and fluid flow in either direction
within the front washer plumbing is prevented.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the wiper arms from the wiper pivots.
(Refer to 8 - ELECTRICAL/FRONT WIPERS/WASH-
ERS/FRONT WIPER ARMS - REMOVAL).
(3) Open the hood and pull the hood to plenum
seal off of the forward flanges of the cowl grille cover
and the plenum panel.
Fig. 2 Wiper Blade Inspection
1 - WORN OR UNEVEN EDGES
2 - ROAD FILM OR FOREIGN MATERIAL DEPOSITS
3 - HARD, BRITTLE, OR CRACKED
4 - DEFORMED OR FATIGUED
5 - SPLIT
6 - DAMAGED SUPPORT COMPONENTS
WJFRONT WIPERS/WASHERS 8R - 9
FRONT WIPERS/WASHERS (Continued)

(4) Remove the six plastic nuts (2 short and 4
long) that secure the cowl grille cover to the studs on
the cowl top panel near the base of the windshield
(Fig. 3).
(5) Lift the left end of the cowl grille cover off of
the cowl plenum panel far enough to access the front
washer plumbing.
(6) Disconnect the engine compartment washer
hose from the cowl grille cover washer hose at the
plastic elbow connector.
(7) Remove the cowl grille cover from the cowl ple-
num and cowl top panels through the opening
between the hood and the base of the windshield.
(8) From the underside of the cowl grille cover, dis-
connect the washer hoses from the three barbed nip-
ples of the wye fitting/check valve unit.
(9) Remove the wye fitting/check valve unit from
the underside of the cowl grille cover.
INSTALLATION
(1) Position the wye fitting/check valve unit to the
underside of the cowl grille cover.
(2) From the underside of the cowl grille cover,
reconnect the three washer hoses to the barbed nip-
ples of the wye fitting/check valve unit.
(3) Reinstall the washer hoses for the front washer
nozzles into their routing clips on the underside of
the cowl grille cover.
(4) Position the cowl grille cover onto the cowl ple-
num and cowl top panels through the opening
between the hood and the base of the windshield
(Fig. 3).(5) Lift the left end of the cowl grille cover off of
the cowl plenum panel far enough to access the front
washer plumbing.
(6) Reconnect the cowl grille cover washer hose to
the engine compartment washer hose at the elbow
connector.
(7) Install the six plastic nuts that secure the cowl
grille cover to the studs on the cowl top panel near
the base of the windshield. These nuts are to be
installed by pushing them onto the studs in the fol-
lowing sequence:
(a) First, install the short nuts to the third stud
from the right, then the second stud from the left.
(b) Next, install the long nuts to the right out-
board stud, then the left outboard stud.
(c) Finally, install the two remaining long nuts
to the third stud from the left, then the second
stud from the right.
(8) Starting at the ends and working toward the
center, push the hood to plenum seal onto the for-
ward flanges of the cowl grille cover and the plenum
panel.
(9) Reinstall the wiper arms onto the wiper pivots.
(Refer to 8 - ELECTRICAL/FRONT WIPERS/WASH-
ERS/FRONT WIPER ARMS - INSTALLATION).
(10) Reconnect the battery negative cable.
FRONT WASHER HOSES/
TUBES
DESCRIPTION
The front washer plumbing consists of a small
diameter rubber hose that is routed from the barbed
outlet nipple of the front washer pump/motor on the
washer reservoir along the filler neck into the engine
compartment. In the engine compartment, a molded
plastic in-line fitting with barbed nipples joins the
washer hose to another section of hose that is routed
near the left headlamp and dash wire harness to the
cowl plenum area. The engine compartment washer
hose passes from the engine compartment into the
cowl plenum area through a dedicated hole with a
rubber grommet near the left end of the cowl plenum
panel. A molded plastic elbow fitting with barbed nip-
ples joins the engine compartment hose to the cowl
grille cover hose. The cowl grille cover washer hose is
routed through routing clips on the underside of the
cowl grille cover to a molded plastic wye fitting with
barbed nipples and an integral check valve. The cowl
grille cover hose is connected to one nipple on the
wye fitting and the two washer nozzle hoses are con-
nected to the other two wye fitting nipples. The
washer nozzle hoses are routed along the underside
of the cowl grille cover to the two washer nozzles.
Fig. 3 Cowl Grille Cover Remove/Install
1 - WASHER HOSE CONNECTION
2 - STUDS (6)
3 - COWL GRILLE COVER
4 - PLASTIC NUT (6)
8R - 10 FRONT WIPERS/WASHERSWJ
FRONT CHECK VALVE (Continued)

REAR WIPERS/WASHERS
TABLE OF CONTENTS
page page
REAR WIPERS/WASHERS
DESCRIPTION.........................33
OPERATION...........................34
DIAGNOSIS AND TESTING - REAR WIPER &
WASHER SYSTEM....................35
CLEANING - REAR WIPER & WASHER
SYSTEM............................37
INSPECTION - REAR WIPER & WASHER
SYSTEM............................37
REAR WASHER HOSES/TUBES
DESCRIPTION.........................38
OPERATION...........................39
REAR WASHER NOZZLE
DESCRIPTION.........................39
OPERATION...........................39
REMOVAL.............................39
INSTALLATION.........................40
REAR WASHER PUMP/MOTOR
DESCRIPTION.........................40
OPERATION...........................40REMOVAL.............................41
INSTALLATION.........................41
REAR WIPER ARM
DESCRIPTION.........................41
OPERATION...........................42
REMOVAL.............................42
INSTALLATION.........................42
REAR WIPER BLADE
DESCRIPTION.........................43
OPERATION...........................43
REMOVAL.............................44
INSTALLATION.........................44
REAR WIPER MODULE
DESCRIPTION.........................44
OPERATION...........................45
REMOVAL.............................45
INSTALLATION.........................45
WIPER ARM PARK RAMP
REMOVAL.............................46
INSTALLATION.........................46
REAR WIPERS/WASHERS
DESCRIPTION
An electrically operated fixed interval intermittent
rear wiper and washer system is standard factory-in-
stalled equipment on this model. The rear wiper and
washer system includes the following major compo-
nents, which are described in further detail else-
where in this service information:
²Rear Washer Nozzle- The rear washer nozzle
is secured by a snap fit onto the top of the liftgate
outer panel above the liftgate glass. The rear washer
nozzle includes an integral check valve. The rear
washer system plumbing is concealed within and
routed through the interior of the vehicle.
²Rear Washer Pump/Motor- The rear washer
pump/motor unit is located in a dedicated hole on the
lower outboard side of the washer reservoir, ahead of
the left front wheel housing. The rear washer pump
mounting hole is located higher on the reservoir than
the front washer pump mounting hole.
²Rear Wiper Arm- The single rear wiper arm is
secured by a nut directly to the rear wiper module
output shaft, which extends through the liftgate
outer panel near the base of the liftgate glass.²Rear Wiper Arm Park Ramp- The molded
rubber rear wiper arm park ramp is secured with a
screw to the liftgate outer panel, just below the right
side of the liftgate glass. When the rear wiper system
is not in operation, the rear wiper arm is parked on
this ramp so that it will not interfere with or be
damaged by liftgate flip-up glass operation.
²Rear Wiper Blade- The single rear wiper
blade is secured to the rear wiper arm, and is moved
off of the liftgate glass when the rear wiper system is
not in operation.
²Rear Wiper Module- The rear wiper module
output shaft is the only visible component of the rear
wiper module. The remainder of the module is con-
cealed within the liftgate beneath the liftgate glass
opening. The rear wiper module includes the module
bracket, the rear wiper motor, and the rear wiper
module electronic control circuitry.
²Right Multi-Function Switch- The right
(wiper) multi-function switch is secured to the right
side of the multi-function switch mounting housing
near the top of the steering column. Only the control
stalk for the right multi-function switch is visible,
the remainder of the switch is concealed beneath the
steering column shrouds. The right multi-function
switch contains all of the switches and control cir-
cuitry for both the front and rear wiper and washer
systems.
WJREAR WIPERS/WASHERS 8R - 33

along the left roof side rail to the rear of the vehicle.
At the rear of the vehicle, the headliner hose is
routed above the headliner and along the upper lift-
gate opening panel toward the right side of the vehi-
cle. The headliner hose then passes through a hole
with a rubber grommet in the upper liftgate opening
panel and through another hole with a rubber grom-
met into the upper inner liftgate panel to the rear
washer nozzle.
Washer hose is available for service only as roll
stock, which must then be cut to length. The head-
liner washer hose is integral to the headliner unit
and, if faulty or damaged, the headliner unit must be
replaced. The molded plastic washer hose fittings
cannot be repaired. If these fittings are faulty or
damaged, they must be replaced.
OPERATION
Washer fluid in the washer reservoir is pressurized
and fed by the rear washer pump/motor through the
rear washer system plumbing and fittings to the rear
washer nozzle on the liftgate outer panel above the
liftgate glass. Whenever routing the washer hose or a
wire harness containing a washer hose, it must be
routed away from hot, sharp, or moving parts; and,
sharp bends that might pinch the hose must be
avoided.
REAR WASHER NOZZLE
DESCRIPTION
The rear washer nozzle is a fluidic type unit that
includes an integral check valve (Fig. 3). The nozzle
is constructed of molded plastic and has a rubber
seal and integral snap features on the back of it. The
nozzle is secured by a snap fit in a dedicated mount-
ing hole in the liftgate outer panel above the liftgate
flip-up glass. Within the rear nozzle body, a small
check ball is held against an integral valve seat at
the inlet end of the nozzle by a small coiled spring.
The rear washer nozzle and check valve unit cannot
be adjusted or repaired. If faulty or damaged, the
entire nozzle and check valve unit must be replaced.
OPERATION
The rear washer nozzle is designed to dispense
washer fluid into the wiper pattern area on the out-
side of the liftgate glass. Pressurized washer fluid is
fed to the nozzle from the washer reservoir by the
rear washer pump/motor through a single hose,
which is attached to a barbed nipple on the back of
the rear washer nozzle. The rear washer nozzle
incorporates a fluidic design, which causes the nozzle
to emit the pressurized washer fluid as an oscillating
stream to more effectively cover a larger area of the
glass area to be cleaned. The integral rear nozzle
check valve prevents washer fluid from draining out
of the rear washer supply hoses back to the washer
reservoir. This drain-back would result in a lengthy
delay from when the rear washer switch is actuated
until washer fluid was dispensed through the rear
washer nozzle, because the rear washer pump would
have to refill the rear washer plumbing from the res-
ervoir to the nozzle. The check valve also prevents
washer fluid from siphoning through the rear washer
nozzle after the rear washer system is turned Off.
When the rear washer pump pressurizes and pumps
washer fluid from the reservoir through the rear
washer plumbing, the fluid pressure overrides the
spring pressure applied to the check ball within the
valve and unseats the check ball, allowing washer
fluid to flow to the rear washer nozzle. When the
rear washer pump stops operating, spring pressure
seats the check ball in the valve and fluid flow in
either direction within the rear washer plumbing is
prevented.
REMOVAL
The check valve for the rear washer nozzle is inte-
gral to the nozzle.
(1) Using a trim stick or another suitable wide
flat-bladed tool, gently pry at the sides of the rear
washer nozzle to release the snap features that
secure it in the mounting hole of the liftgate outer
panel.
Fig. 3 Rear Washer Nozzle
1 - HEADLINER WASHER HOSE
2 - ROOF PANEL
3 - REAR WASHER NOZZLE
4 - LIFTGATE
WJREAR WIPERS/WASHERS 8R - 39
REAR WASHER HOSES/TUBES (Continued)

DESCRIPTION SPECIFICATION
Main Bearing Journal
Width
No. 1 27.58 to 27.89 mm
(1.086 to 1.098 in.)
No. 3 32.28 to 32.33 mm
(1.271 to 1.273 in.)
No. 2-4-5-6-7 30.02 to 30.18 mm
(1.182 to 1.188 in.)
Main Bearing Clearance 0.03 to 0.06 mm
(0.001 to 0.0025 in.)
Preferred 0.051 mm (0.002 in.)
Connecting Rod Journal
Diameter 53.17 to 53.23 mm
(2.0934 to 2.0955 in.)
Connecting Rod Journal
Width27.18 to 27.33 mm
(1.070 to 1.076 in.)
Out-of-Round (MAX) 0.013 mm (0.0005 in.)
Taper (MAX) 0.013 mm (0.0005 in.)
CYLINDER BLOCK
Deck Height 240.03 to 240.18 mm
(9.450 to 9.456 in.)
Deck Clearance (Below
Block)0.546 mm (0.0215 in.)
Cylinder Bore Diameter
Standard 98.45 to 98.48 mm
(3.8759 to 3.8775 in.)
Taper 0.025 mm (0.001 in.)
Out-ofRound 0.025 mm (0.001 in.)
Tappet Bore Diameter 23.000 to 23.025 mm
(0.9055 to 0.9065 in.)
Flatness 0.03 mm per 25 mm
(0.001 in. per 1 in.)
0.05 mm per 152 mm
(0.002 in. per 6 in.)
Flatness Max. 0.20 mm max. for total
lengthDESCRIPTION SPECIFICATION
(0.008 in. max. for total
length)
Main Bearing Bore
Diameter68.3514 to 68.3768 mm
(2.691 to 2.692 in.)
CONNECTING ROD
Total Weight (Less
Bearing)663 to 671 grams
(23.39 to 23.67 oz.)
Length (Center-to-Center) 155.52 to 155.62 mm
(6.123 to 6.127 in.)
Piston Pin Bore Diameter 23.59 to 23.62 mm
(0.9288 to 0.9298 in.)
Bore (Less Bearings) 56.08 to 56.09 mm
(2.2080 to 2.2085 in.)
Bearing Clearance 0.025 to 0.076 mm
(0.001 to 0.003 in.)
Preferred 0.044 to 0.050 mm
(0.0015 to 0.0020 in.)
Side Clearance 0.25 to 0.48 mm
(0.010 to 0.019 in.)
Twist (Max.) 0.002 mm per mm
(0.002 in. per inch)
Bend (Max.) 0.002 mm per mm
(0.002 in. per inch.)
CYLINDER COMPRESSION PRESSURE
Pressure Range 827 to 1,034 kPa
(120 to 150 psi)
Max. Variation Between
Cylinders 206 kPa (30 psi)
CYLINDER HEAD
Combustion Chamber 55.22 to 58.22 cc
(3.37 to 3.55 cu. in.)
Valve Guide I.D.
(Integral)7.95 to 7.97 mm
(0.313 to 0.314 in.)
WJENGINE - 4.0L 9 - 15
ENGINE - 4.0L (Continued)