2002 JEEP GRAND CHEROKEE Head light

EXHAUST MANIFOLD - RIGHT
DESCRIPTION
The exhaust manifolds are log style with a pat-
ented flow enhancing design to maximize perfor-
mance. The exhaust manifolds are made of high
silicon molybdenum cast iron. A perforated core
graphite exhaust manifold gasket is used to improve
sealing to the cylinder head. The exhaust manifolds
are covered by a three layer laminated heat shield
for thermal protection and noise reduction. The heat
shields are fastened with a torque prevailing nut
that is backed off slightly to allow for the thermal
expansion of the exhaust manifold.
REMOVAL
(1) Disconnect negative cable for battery.
(2) Remove battery from vehicle.
(3) Remove Power Distribution Center (PDC) fas-
teners and set aside.
(4) Remove battery tray assembly.
(5) Remove washer bottle assembly
(6) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
Fig. 107 Exhaust ManifoldÐLeft
ITEM DESCRIPTION TORQUE ITEM DESCRIPTION TORQUE
1 Stud (Qty 2)
25 N´m (18 ft. lbs.)4 Nut (Qty 2) 8 N´m (72 in. lbs.),
then loosen 45
degrees 2 Bolt (Qty 4) 5 Nut (Qty 2)
3 Stud (Qty 2)
WJENGINE - 4.7L 9 - 139
EXHAUST MANIFOLD - LEFT (Continued)

INSPECTION
Inspect the following components:
²Sprockets for excessive tooth wear. Some tooth
markings are normal and not a cause for sprocket
replacement.
²Idler sprocket assembly bushing and shaft for
excessive wear.
²Idler sprocket assembly spline joint. The joint
should be tight with no backlash or axial movement.
²Chain guides and tensioner arms. Replace these
parts if grooving in plastic face is more than 1 mm
(0.039 in.) deep. If plastic face is severely grooved or
melted, the tensioner lube jet may be clogged. The
tensioner should be replaced.
²secondary chain tensioner piston and ratcheting
device. Inspect for evidence of heavy contact between
tensioner piston and tensioner arm. If this condition
exist the tensioner and tensioner arm should be
replaced.
²Primary chain tensioner plastic faces. Replace as
required (Fig. 127).
INSTALLATION
(1) Using a vise, lightly compress the secondary
chain tensioner piston until the piston step is flush
with the tensioner body. Using a pin or suitable tool,
release ratchet pawl by pulling pawl back against
spring force through access hole on side of tensioner.
While continuing to hold pawl back, Push ratchet
device to approximately 2 mm from the tensioner
Fig. 124 Camshaft Position SensorÐRemoval
1 - CRANKSHAFT POSITION SENSOR
2 - CYLINDER HEAD COVER
3 - CAMSHAFT POSITION SENSOR
4 - RIGHT SIDE CYLINDER BLOCK
Fig. 125 Camshaft RotationÐLeft Side
1 - CAMSHAFT SPROCKET AND CHAIN
2 - ADJUSTABLE PLIERS
3 - CAMSHAFT
Fig. 126 Camshaft RotationÐRight Side
1 - ADJUSTABLE PLIERS
2 - CAMSHAFT DOWEL
WJENGINE - 4.7L 9 - 149
TIMING BELT/CHAIN AND SPROCKETS (Continued)

(8) Align primary chain double plated links with
the timing mark at 12 o'clock on the idler sprocket.
Align the primary chain single plated link with the
timing mark at 6 o'clock on the crankshaft sprocket
(Fig. 127).
(9) Lubricate idler shaft and bushings with clean
engine oil.
(10) Install all chains, crankshaft sprocket, and
idler sprocket as an assembly (Fig. 130). After guid-
ing both secondary chains through the block and cyl-
inder head openings, affix chains with a elastic strap
or the equivalent, This will maintain tension on
chains to aid in installation.
NOTE: It will be necessary to slightly rotate cam-
shafts for sprocket installation.
(11) Align left camshaft sprocket ªLº dot to plated
link on chain.
(12) Align right camshaft sprocket ªRº dot to
plated link on chain.
CAUTION: Remove excess oil from the camshaft
sprocket bolt. Failure to do so can result in over-
torque of bolt resulting in bolt failure.
Fig. 128 Resetting Secondary Chain Tensioners
1 - VISE
2 - INSERT LOCK PIN
3 - RATCHET PAWL
4 - RATCHET
5 - PISTON
Fig. 129 Installing Secondary Timing Chains on
Idler Sprocket
1 - LOCK ARM
2 - RIGHT CAMSHAFT CHAIN
3 - SECONDARY CHAINS RETAINING PINS (4)
4 - IDLER SPROCKET
5 - LEFT CAMSHAFT CHAIN
6 - SPECIAL TOOL 8515
Fig. 130 Installing Idler Gear, Primary and
Secondary Timing Chains
1 - SPECIAL TOOL 8515
2 - PRIMARY CHAIN IDLER SPROCKET
3 - CRANKSHAFT SPROCKET
WJENGINE - 4.7L 9 - 151
TIMING BELT/CHAIN AND SPROCKETS (Continued)

(9) Disconnect speed control cable at throttle body
(if equipped). Refer to Speed Control Cable.
(10) Disconnect automatic transmission cable at
throttle body (if equipped).
(11) Remove cable routing bracket at intake mani-
fold.
(12) Clean dirt/debris from each fuel injector at
intake manifold.
(13) Remove fuel rail mounting nuts/bolts (Fig.
24).
(14) Remove fuel rail by gently rocking until all
fuel injectors have cleared machined holes at intake
manifold.
(15) If fuel injectors are to be removed, refer to
Fuel Injector Removal/Installation.
INSTALLATION
INSTALLATION - 4.7L
(1) If fuel injectors are to be installed, refer to Fuel
Injector Removal/Installation.
(2) Apply a small amount of engine oil to each fuel
injector o-ring. This will help in fuel rail installation.
(3) Position fuel rail/fuel injector assembly to
machined injector openings in cylinder head.
(4) Guide each injector into cylinder head. Be care-
ful not to tear injector o-rings.(5) Pushrightside of fuel rail down until fuel
injectors have bottomed on cylinder head shoulder.
Pushleftfuel rail down until injectors have bot-
tomed on cylinder head shoulder.
(6) Install 4 fuel rail mounting bolts and tighten to
27 N´m (20 ft. lbs.).
(7) Install ignition coils. Refer to Ignition Coil
Removal/Installation.
(8) Connect electrical connectors to throttle body.
(9) Connect electrical connectors to MAP and IAT
sensors.
(10) Connect electrical connectors at all fuel injec-
tors. To install connector, refer to (Fig. 23). Push con-
nector onto injector (1) and then push and lock red
colored slider (2). Verify connector is locked to injec-
tor by lightly tugging on connector.
(11) Connect vacuum lines to throttle body.
(12) Connect fuel line latch clip and fuel line to
fuel rail. Refer to Quick-Connect Fittings.
(13) Connect wiring to rear of generator.
(14) Install air box to throttle body.
(15) Install air duct to air box.
(16) Connect battery cable to battery.
(17) Start engine and check for leaks.
INSTALLATION - 4.0L
(1) If fuel injectors are to be installed, refer to Fuel
Injector Removal/Installation.
(2) Clean each injector bore at intake manifold.
(3) Apply a small amount of clean engine oil to
each injector o-ring. This will aid in installation.
(4) Position tips of all fuel injectors into the corre-
sponding injector bore in intake manifold. Seat injec-
tors into manifold.
(5) Install and tighten fuel rail mounting bolts to
11  3 N´m (100  25 in. lbs.) torque.
(6) Connect electrical connectors at all fuel injec-
tors. To install connector, refer to (Fig. 25). Push con-
nector onto injector (1) and then push and lock red
colored slider (2). Verify connector is locked to injec-
tor by lightly tugging on connector.
(7) Connect fuel line and fuel line latch clip to fuel
rail. Refer Quick-Connect Fittings.
(8) Install protective cap to pressure test port fit-
ting (if equipped).
(9) Install cable routing bracket to intake mani-
fold.
(10) Connect throttle cable at throttle body.
(11) Connect speed control cable at throttle body (if
equipped).
(12) Connect automatic transmission cable at
throttle body (if equipped).
(13) Install oxygen sensor wiring clip nuts to fuel
rail mounting studs (certain emissions packages
only).
Fig. 25 Remove/Install Injector ConnectorÐ4.0L
Engine
14 - 18 FUEL DELIVERYWJ
FUEL RAIL (Continued)

(5) Push sensor against flywheel/drive plate. With
sensor pushed against flywheel/drive plate, tighten
mounting bolt to 7 N´m (60 in. lbs.) torque.
(6) Route sensor wiring harness into wire shield.
(7) Connect sensor pigtail harness electrical con-
nector to main wiring harness.
INSTALLATION - 4.7L
(1) Clean out machined hole in engine block.
(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into engine block with a slight
rocking action. Do not twist sensor into position as
damage to o-ring may result.
CAUTION: Before tightening sensor mounting bolt,
be sure sensor is completely flush to cylinder
block. If sensor is not flush, damage to sensor
mounting tang may result.
(4) Install mounting bolt and tighten to 28 N´m
(21 ft. lbs.) torque.
(5) Connect electrical connector to sensor.
(6) Install starter motor. Refer to Starter Removal/
Installation.
FUEL INJECTOR
DESCRIPTION
A separate fuel injector (Fig. 24) is used for each
individual cylinder.
OPERATION
OPERATION
The fuel injectors are electrical solenoids. The
injector contains a pintle that closes off an orifice at
the nozzle end. When electric current is supplied to
the injector, the armature and needle move a short
distance against a spring, allowing fuel to flow out
the orifice. Because the fuel is under high pressure, a
fine spray is developed in the shape of a pencil
stream. The spraying action atomizes the fuel, add-
ing it to the air entering the combustion chamber.
The top (fuel entry) end of the injector (Fig. 24) is
attached into an opening on the fuel rail.
The nozzle (outlet) ends of the injectors are posi-
tioned into openings in the intake manifold just
above the intake valve ports of the cylinder head.
The engine wiring harness connector for each fuel
injector is equipped with an attached numerical tag
(INJ 1, INJ 2 etc.). This is used to identify each fuel
injector.
The injectors are electrically energized, individu-
ally and in a sequential order by the Powertrain Con-
trol Module (PCM). The PCM will adjust injector
pulse width by switching the ground path to each
individual injector on and off. Injector pulse width is
the period of time that the injector is energized. The
PCM will adjust injector pulse width based on vari-
ous inputs it receives.
Battery voltage is supplied to the injectors through
the ASD relay.
The PCM determines injector pulse width based on
various inputs.
OPERATION - PCM OUTPUT
The nozzle ends of the injectors are positioned into
openings in the intake manifold just above the intake
valve ports of the cylinder head. The engine wiring
harness connector for each fuel injector is equipped
with an attached numerical tag (INJ 1, INJ 2 etc.).
This is used to identify each fuel injector with its
respective cylinder number.
The injectors are energized individually in a
sequential order by the Powertrain Control Module
(PCM). The PCM will adjust injector pulse width by
switching the ground path to each individual injector
on and off. Injector pulse width is the period of time
that the injector is energized. The PCM will adjust
injector pulse width based on various inputs it
receives.
Battery voltage (12 volts +) is supplied to the injec-
tors through the ASD relay. The ASD relay will shut-
down the 12 volt power source to the fuel injectors if
the PCM senses the ignition is on, but the engine is
not running. This occurs after the engine has not
been running for approximately 1.8 seconds.
Fig. 24 Fuel InjectorÐ4.0L/4.7L Engines
1 - FUEL INJECTOR
2 - NOZZLE
3 - TOP (FUEL ENTRY)
WJFUEL INJECTION 14 - 43
CRANKSHAFT POSITION SENSOR (Continued)

(4) Close flip up glass panel and verify proper
operation.
(5)
Install liftgate trim panel, refer to (Refer to 23 -
BODY/DECKLID/HATCH/LIFTGATE/TAILGATE/TRIM
PANEL - INSTALLATION).
FLIP-UP GLASS LATCH
STRIKER
REMOVAL
(1) Raise flip up glass panel.
(2) Mark the position of the handle/striker on the
glass panel.
(3) Remove the screws attaching the handle/striker
to the glass.
INSTALLATION
(1) Position the handle/striker on the glass panel
and align the reference marks.
(2) Install the screws attaching the handle/striker
to the glass panel. Tighten the fasteners to 6 N´m (60
in. lbs.).
FLIP-UP GLASS SWITCH
REMOVAL
(1) Remove license plate lamp housing/trim panel
from liftgate, refer to (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - EXTERIOR/LICENSE PLATE
LAMP UNIT - REMOVAL).
(2) Squeeze the locking tabs inward to release the
switch from the housing.
(3) Disconnect the switch harness connector,
remove the switch from the housing.
INSTALLATION
(1) Install switch harness connector.(2) Position switch in housing, snap switch into
place.
(3) Install license plate lamp housing/trim panel
onto liftgate, refer to (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - EXTERIOR/LICENSE PLATE
LAMP UNIT - INSTALLATION).
HINGE
REMOVAL
NOTE: It is not necessary to remove the liftgate to
replace one or both hinges. The hinges can be
replaced one at a time.
(1) Open the liftgate. Support the liftgate for ease
of repair.
(2) Remove the liftgate header trim panel.
(3) Mark the hinge location with a grease pencil or
other suitable device.
(4) Remove the hinge screws (Fig. 5).
(5) Remove hinge.
INSTALLATION
NOTE: It is not necessary to remove the liftgate to
replace one or both hinges. The hinges can be
replaced one at a time.
(1) Position the hinge on the roof panel and on the
liftgate. (Use 3MŸ Fast and Firm or equivalent on
the hinge to body mating surfaces as a sealant.
(2) Install and tighten hinge screws at roof panel
to 28N´m (21 ft. lbs.).
(3) Install hinge screws at liftgate. Tighten screws
to 28N´m (21 ft. lbs.).
(4) Install liftgate header trim panel.
(5) Check the liftgate for proper alignment and
operation.
WJDECKLID/HATCH/LIFTGATE/TAILGATE 23 - 7
FLIP-UP GLASS LATCH (Continued)

INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) If the vehicle is not equipped with the optional
automatic headlamps light sensor/vehicle theft secu-
rity system indicator, be certain that the hole plug is
installed in the clearance hole located to the out-
board side of the driver side defroster outlet in the
instrument panel top cover (Fig. 22).
(2) Before installing the top cover onto the top of
the instrument panel, be certain that the rubber top
cover seal is properly positioned on the forward edge
of the top cover panel.
(3) Position the top cover onto the top of the
instrument panel.
(4) Align the four snap clips on the top cover with
the snap clip receptacles in the instrument panel top
pad.
(5) Press firmly downward on the top cover over
each of the four snap clip locations until each of the
snap clips is fully seated in their receptacles in the
instrument panel top pad.
(6) Reconnect the battery negative cable.
INSTRUMENT PANEL TOP PAD
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.(1) Disconnect and isolate the battery negative
cable.
(2) Remove the trim from the right and left A-pil-
lars. (Refer to 23 - BODY/INTERIOR/A-PILLAR
TRIM - REMOVAL).
(3) Remove the top cover from the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL TOP COVER - REMOVAL).
(4) Remove the four nuts that secure the instru-
ment panel top pad to the studs on the dash panel
near the windshield fence line (Fig. 23).
(5) Remove the speakers from the instrument
panel top pad. (Refer to 8 - ELECTRICAL/AUDIO/
SPEAKER - REMOVAL - INSTRUMENT PANEL
SPEAKER).
(6) Disengage the retainer that secures each of the
two instrument panel wire harness speaker take outs
to the mounting hole in the instrument panel top
pad. Tuck the loose ends of these speaker take outs
down the defroster ducts to keep them out of the way
during the remainder of this procedure.
(7) If the vehicle is so equipped, remove the two
screws that secure the automatic headlamp light sen-
sor/vehicle theft security system indicator unit to the
instrument panel top pad just outboard of the driver
side defroster outlet. Move the sensor/indicator unit
towards the windshield to keep it out of the way dur-
ing the remainder of this procedure.
(8) Remove the cluster bezel from the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
CLUSTER BEZEL - REMOVAL).
(9) Remove the instrument cluster from the instru-
ment panel. (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - REMOVAL).
(10) Remove the steering column opening cover
from the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - REMOVAL).
(11) Roll the glove box down from the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
GLOVE BOX - STANDARD PROCEDURE - GLOVE
BOX ROLL DOWN).
(12) Remove the end cap from the passenger side
lower outboard end of the instrument panel. (Refer to
23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL END CAP - REMOVAL).
(13) Remove the lower right center bezel from the
instrument panel. (Refer to 23 - BODY/INSTRU-
MENT PANEL/IP LOWER RIGHT CENTER BEZEL
- REMOVAL).
(14) Remove the glove box lamp and switch from
the instrument panel. (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - INTERIOR/GLOVE BOX
LAMP/SWITCH - REMOVAL).
23 - 52 INSTRUMENT PANEL SYSTEMWJ
INSTRUMENT PANEL TOP COVER (Continued)

(6) Reach through the front bin opening of the
floor console to access and tighten the two nuts that
secure the center floor tunnel bracket to the studs on
the floor panel transmission tunnel. Tighten the nuts
to 11.8 N´m (105 in. lbs.).
(7) Reinstall the front bin into the floor console.
(Refer to 23 - BODY/INTERIOR/FLOOR CONSOLE -
INSTALLATION).
(8) Install and tighten all of the screws that secure
the perimeter of the top pad to the instrument panel
structural duct. Tighten the screws to 2.2 N´m (20 in.
lbs.).
(9) Install and tighten the four screws that secure
the heater-A/C control to the instrument panel struc-
tural duct. Tighten the screws to 2.2 N´m (20 in.
lbs.).
(10) Install and tighten the four screws that secure
the radio to the instrument panel structural duct.
Tighten the screws to 2.2 N´m (20 in. lbs.).
(11) Reinstall the center lower bezel onto the
instrument panel. (Refer to 23 - BODY/INSTRU-
MENT PANEL/IP CENTER BEZEL - LOWER -
INSTALLATION).
(12) Reinstall the center upper bezel onto the
instrument panel. (Refer to 23 - BODY/INSTRU-
MENT PANEL/IP CENTER BEZEL - UPPER -
INSTALLATION).
(13) Install and tighten the two large screws on
the glove box opening upper reinforcement that
secure the top pad to the instrument panel structural
duct (Fig. 24). Tighten the screws to 11.8 N´m (105
in. lbs.).
(14) Install and tighten the two small screws on
the glove box opening upper reinforcement that
secure the panel outlets to the instrument panel
structural duct. Tighten the screws to 2.2 N´m (20 in.
lbs.).
(15) Reinstall the glove box lamp and switch into
the instrument panel. (Refer to 8 - ELECTRICAL/
LAMPS/LIGHTING - INTERIOR/GLOVE BOX
LAMP/SWITCH - INSTALLATION).
(16) Reinstall the lower right center bezel onto the
instrument panel. (Refer to 23 - BODY/INSTRU-
MENT PANEL/IP LOWER RIGHT CENTER BEZEL
- INSTALLATION).(17) Reinstall the end cap onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL END CAP - INSTALLA-
TION).
(18) Roll the glove box back up into the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
GLOVE BOX - STANDARD PROCEDURE - GLOVE
BOX ROLL DOWN).
(19) Reinstall the steering column opening cover
onto the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).
(20) Reinstall the instrument cluster into the
instrument panel. (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - INSTALLATION).
(21) Reinstall the cluster bezel onto the instru-
ment panel. (Refer to 23 - BODY/INSTRUMENT
PANEL/CLUSTER BEZEL - INSTALLATION).
(22) If the vehicle is so equipped, position the
automatic headlamp light sensor/vehicle theft secu-
rity system indicator unit to the instrument panel
top pad just outboard of the driver side defroster out-
let. Install and tighten the two screws that secure
the sensor/indicator unit. Tighten the screws to 2.2
N´m (20 in. lbs.).
(23) Engage the retainer that secures each of the
two instrument panel wire harness speaker take outs
to the mounting hole in the instrument panel top
pad.
(24) Reinstall the speakers onto the instrument
panel top pad. (Refer to 8 - ELECTRICAL/AUDIO/
SPEAKER - INSTALLATION - INSTRUMENT
PANEL SPEAKER).
(25) Install and tighten the four nuts that secure
the instrument panel top pad to the studs on the
dash panel near the windshield fence line (Fig. 23).
Tighten the nuts to 11.8 N´m (105 in. lbs.).
(26) Reinstall the top cover onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL TOP COVER - INSTALLA-
TION).
(27) Reinstall the trim onto the right and left
A-pillars. (Refer to 23 - BODY/INTERIOR/A-PILLAR
TRIM - INSTALLATION).
(28) Reconnect the battery negative cable.
WJINSTRUMENT PANEL SYSTEM 23 - 55
INSTRUMENT PANEL TOP PAD (Continued)