2002 JEEP GRAND CHEROKEE lock

INSTALLATION
INSTALLATION - 4.0L
SENSOR ONLY - 4.0L
The Camshaft Position Sensor (CMP) on the 4.0L
6±cylinder engine is bolted to the top of the oil pump
drive shaft assembly (Fig. 6). The sensor and drive
shaft assembly is located on the right side of the
engine near the oil filter (Fig. 7).
(1) Install sensor to oil pump drive.
(2) Install 2 sensor mounting bolts and tighten to
2 N´m (15 in. lbs.) torque.
(3) Connect electrical connector to CMP sensor.
OIL PUMP DRIVE AND SENSOR - 4.0L
(1) Clean oil pump drive mounting hole area of
engine block.
(2) Install new oil pump drive-to-engine block gas-
ket.
(3) Temporarily install a toothpick or similar tool
through access hole at side of oil pump drive housing.
Align toothpick into mating hole on pulse ring (Fig.
8).(4) Install oil pump drive into engine while align-
ing into slot on oil pump. Rotate oil pump drive back
to its original position and install hold-down clamp
and bolt. Finger tighten bolt. Do not do a final tight-
ening of bolt at this time.
(5) If engine crankshaft or camshaft has been
rotated, such as during engine tear-down, CMP sen-
sor relationship must be reestablished.
(a) Remove ignition coil rail assembly. Refer to
Ignition Coil Removal/Installation.
(b) Remove cylinder number 1 spark plug.
(c) Hold a finger over the open spark plug hole.
Rotate engine at vibration dampener bolt until
compression (pressure) is felt.
(d) Slowly continue to rotate engine. Do this
until timing index mark on vibration damper pul-
ley aligns with top dead center (TDC) mark (0
degree) on timing degree scale (Fig. 9). Always
rotate engine in direction of normal rotation. Do
not rotate engine backward to align timing marks.
(e) Install oil pump drive into engine while
aligning into slot on oil pump. If pump drive will
not drop down flush to engine block, the oil pump
slot is not aligned. Remove oil pump drive and
align slot in oil pump to shaft at bottom of drive.
Install into engine. Rotate oil pump drive back to
its original position and install hold-down clamp
and bolt. Finger tighten bolt. Do not do a final
tightening of bolt at this time.
(f) Remove toothpick from housing.
(6) Install sensor to oil pump drive. After installa-
tion, the CMP sensor should face rear of engine 0É.
(7) Install 2 sensor mounting bolts and tighten to
2 N´m (15 in. lbs.) torque.
(8) Connect electrical connector to CMP sensor.
(9) If removed, install spark plug and ignition coil
rail.
To verify correct rotational position of oil pump
drive, the DRB scan tool must be used.
WARNING: WHEN PERFORMING THE FOLLOWING
TEST, THE ENGINE WILL BE RUNNING. BE CARE-
FUL NOT TO STAND IN LINE WITH THE FAN
BLADES OR FAN BELT. DO NOT WEAR LOOSE
CLOTHING.
(10) Connect DRB scan tool to data link connector.
The data link connector is located in passenger com-
partment, below and to left of steering column.
(11) Gain access to SET SYNC screen on DRB.
(12) Follow directions on DRB screen and start
engine. Bring to operating temperature (engine must
be in ªclosed loopº mode).
(13) With engine running atidle speed, the words
IN RANGE should appear on screen along with 0É.
This indicates correct position of oil pump drive.
Fig. 10 CMP LocationÐ4.7L Engine
1 - RIGHT CYLINDER HEAD
2 - CAMSHAFT POSITION SENSOR
3 - MOUNTING BOLT
4 - ELEC. CONNECTOR
8I - 8 IGNITION CONTROLWJ
CAMSHAFT POSITION SENSOR (Continued)

OPERATION
Although cylinder firing order is the same as 4.0L
Jeep engines of previous years, spark plug firing is
not. The 3 coils dual-fire the spark plugs on cylinders
1-6, 2-5 and/or 3-4. When one cylinder is being fired
(on compression stroke), the spark to the opposite
cylinder is being wasted (on exhaust stroke).
Battery voltage is supplied to the three ignition
coils from the ASD relay. The Powertrain Control
Module (PCM) opens and closes the ignition coil
ground circuit for ignition coil operation.
Base ignition timing is not adjustable.By con-
trolling the coil ground circuit, the PCM is able to set
the base timing and adjust the ignition timing
advance. This is done to meet changing engine oper-
ating conditions.
The ignition coil is not oil filled. The windings are
embedded in an epoxy compound. This provides heat
and vibration resistance that allows the ignition coil
to be mounted on the engine.
Because of coil design, spark plug cables (second-
ary cables) are not used. The cables are integral
within the coil rail.
REMOVAL
A one-piece coil rail assembly containing three
individual coils is used on the 4.0L engine (Fig. 13).
The coil rail must be replaced as one assembly. The
bottom of the coil is equipped with 6 individual rub-
ber boots (Fig. 13) to seal the 6 spark plugs to the
coil. Inside each rubber boot is a spring. The spring
is used for an electrical contact between the coil and
the top of the spark plug. These rubber boots and
springs are a permanent part of the coil and are not
serviced separately.
(1) Disconnect negative battery cable at battery.
(2) The coil is bolted directly to the cylinder head.
Remove 4 coil mounting bolts (Fig. 14).
(3) Carefully pry up coil assembly from spark
plugs. Do this by prying alternately at each end of
coil until rubber boots have disengaged from all
spark plugs. If boots will not release from spark
plugs, use a commercially available spark plug boot
removal tool. Twist and loosen a few boots from a few
spark plugs to help remove coil.
(4) After coil has cleared spark plugs, position coil
for access to primary electrical connector. Disconnect
connector from coil by pushing slide tab outwards to
right side of vehicle (Fig. 15). After slide tab has been
positioned outwards, push in on secondary release
lock (Fig. 15) on side of connector and pull connector
from coil.
(5) Remove coil from vehicle.
Fig. 13 Ignition Coil AssemblyÐ4.0L 6±Cylinder
Engine
1 - CYL. #6
2 - CYL. #5
3 - CYL. #4
4 - CYL. #3
5 - CYL. #2
6 - CYL. #1
7 - COILS (3)
8 - MOUNTING BOLTS (4)
9 - BOLT BASES (4)
10 - RUBBER BOOTS (6)
Fig. 14 Ignition Coil Rail LocationÐ4.0L 6±Cylinder
Engine
1 - COIL RAIL
2 - COIL MOUNTING BOLTS (4)
3 - COIL
4 - COIL ELECTRICAL CONNECTION
8I - 10 IGNITION CONTROLWJ
COIL RAIL (Continued)

INSTALLATION
(1) Connect engine harness connector to coil by
snapping into position. Move slide tab towards
engine (Fig. 15) for a positive lock.
(2) Position ignition coil rubber boots to all spark
plugs. Push down on coil assembly until bolt bases
have contacted cylinder head
(3) Install 4 coil mounting bolts. Loosely tighten 4
bolts just enough to allow bolt bases to contact cylin-
der head. Do a final tightening of each bolt in steps
down to 29 N´m (250 in. lbs.) torque. Do not apply
full torque to any bolt first.
(4) Connect negative battery cable to battery.
IGNITION COIL
DESCRIPTION
The 4.7L V±8 engine uses 8 dedicated, and individ-
ually fired coil (Fig. 16) for each spark plug. Each
coil is mounted directly to the top of each spark plug
(Fig. 17).
Fig. 15 Ignition Coil Electrical ConnectorÐ4.0L
6±Cylinder Engine
1 - REAR OF VALVE COVER
2 - COIL RAIL
3 - SLIDE TAB
4 - RELEASE LOCK
5 - COIL CONNECTOR
Fig. 16 Ignition CoilÐ4.7L Engine
1 - O-RING
2 - IGNITION COIL
3 - ELECTRICAL CONNECTOR
Fig. 17 Ignition Coil LocationÐ4.7L Engine
1 - IGNITION COIL
2 - COIL ELECTRICAL CONNECTOR
3 - COIL MOUNTING STUD/NUT
WJIGNITION CONTROL 8I - 11
COIL RAIL (Continued)

OPERATION
Battery voltage is supplied to the 8 ignition coils
from the ASD relay. The Powertrain Control Module
(PCM) opens and closes each ignition coil ground cir-
cuit at a determined time for ignition coil operation.
Base ignition timing is not adjustable.By con-
trolling the coil ground circuit, the PCM is able to set
the base timing and adjust the ignition timing
advance. This is done to meet changing engine oper-
ating conditions.
The ignition coil is not oil filled. The windings are
embedded in an epoxy compound. This provides heat
and vibration resistance that allows the ignition coil
to be mounted on the engine.
Because of coil design, spark plug cables (second-
ary cables) are not used.
REMOVAL
An individual ignition coil is used for each spark
plug (Fig. 18). The coil fits into machined holes in the
cylinder head. A mounting stud/nut secures each coil
to the top of the intake manifold (Fig. 19). The bot-
tom of the coil is equipped with a rubber boot to seal
the spark plug to the coil. Inside each rubber boot is
a spring. The spring is used for a mechanical contact
between the coil and the top of the spark plug. These
rubber boots and springs are a permanent part of the
coil and are not serviced separately. An o-ring (Fig.
18) is used to seal the coil at the opening into the cyl-
inder head.
(1) Depending on which coil is being removed, the
throttle body air intake tube or intake box may need
to be removed to gain access to coil.
(2) Disconnect electrical connector (Fig. 19) from
coil by pushing downward on release lock on top of
connector and pull connector from coil.
(3) Clean area at base of coil with compressed air
before removal.
(4) Remove coil mounting nut from mounting stud
(Fig. 19).
(5) Carefully pull up coil from cylinder head open-
ing with a slight twisting action.
(6) Remove coil from vehicle.
INSTALLATION
(1) Using compressed air, blow out any dirt or con-
taminants from around top of spark plug.
(2) Check condition of coil o-ring and replace as
necessary. To aid in coil installation, apply silicone to
coil o-ring.
(3) Position ignition coil into cylinder head opening
and push onto spark plug. Do this while guiding coil
base over mounting stud.
(4) Install mounting stud nut and tighten to 8 N´m
(70 in. lbs.) torque.(5) Connect electrical connector to coil by snapping
into position.
(6) If necessary, install throttle body air tube or
box.
Fig. 18 Ignition CoilÐ4.7L V±8
1 - O-RING
2 - IGNITION COIL
3 - ELECTRICAL CONNECTOR
Fig. 19 Ignition Coil
1 - IGNITION COIL
2 - COIL ELECTRICAL CONNECTOR
3 - COIL MOUNTING STUD/NUT
8I - 12 IGNITION CONTROLWJ
IGNITION COIL (Continued)

IGNITION COIL CAPACITOR
DESCRIPTION
Two coil capacitors are used. One of them is
located near the center of, and on the left side of the
intake manifold (Fig. 20). The other capacitor is
located near the center of, and on the right side of
the intake manifold.
OPERATION
The 2 coil capacitors are used to prevent high-volt-
age spikes from interfering with the operation of cer-
tain powertrain sensors. They are also used to help
prevent radio interference.
REMOVAL
Two coil capacitors are used. One of them is
located near the center of, and on the left side of the
intake manifold (Fig. 21). The other capacitor is
located near the center of, and on the right side of
the intake manifold.
(1) Disconnect electrical connector at coil capacitor
(Fig. 21).
(2) Remove mounting nut.
(3) Remove capacitor from mounting stud.
INSTALLATION
(1) Position capacitor to manifold mounting stud.(2) Install nut and tighten to 8 N´m (70 in. lbs.)
torque.
(3) Connect electrical connector to capacitor (Fig.
21).
KNOCK SENSOR
DESCRIPTION
4.7L High-Output Engine
The 2 knock sensors are bolted into the cylinder
block under the intake manifold.
OPERATION
4.7L High-Output Engine
Two knock sensors are used on the 4.7L V-8 engine
if equipped with the high-output package; one for
each cylinder bank. When the knock sensor detects a
knock in one of the cylinders on the corresponding
bank, it sends an input signal to the Powertrain Con-
trol Module (PCM). In response, the PCM retards
ignition timing for all cylinders by a scheduled
amount.
Knock sensors contain a piezoelectric material
which constantly vibrates and sends an input voltage
(signal) to the PCM while the engine operates. As the
intensity of the crystal's vibration increases, the
knock sensor output voltage also increases.
Fig. 20 Coil Capacitor (Left Side Shown)
1 - ELECTRICAL CONNECTOR
2 - COIL CAPACITOR
3 - MOUNTING NUT
Fig. 21 Coil Capacitor (Left Side Shown)
1 - ELECTRICAL CONNECTOR
2 - COIL CAPACITOR
3 - MOUNTING NUT
WJIGNITION CONTROL 8I - 13

The voltage signal produced by the knock sensor
increases with the amplitude of vibration. The PCM
receives the knock sensor voltage signal as an input.
If the signal rises above a predetermined level, the
PCM will store that value in memory and retard
ignition timing to reduce engine knock. If the knock
sensor voltage exceeds a preset value, the PCM
retards ignition timing for all cylinders. It is not a
selective cylinder retard.
The PCM ignores knock sensor input during engine
idle conditions. Once the engine speed exceeds a
specified value, knock retard is allowed.
Knock retard uses its own short term and long
term memory program.
Long term memory stores previous detonation
information in its battery-backed RAM. The maxi-
mum authority that long term memory has over tim-
ing retard can be calibrated.
Short term memory is allowed to retard timing up
to a preset amount under all operating conditions (as
long as rpm is above the minimum rpm) except at
Wide Open Throttle (WOT). The PCM, using short
term memory, can respond quickly to retard timing
when engine knock is detected. Short term memory
is lost any time the ignition key is turned off.
NOTE: Over or under tightening the sensor mount-
ing bolts will affect knock sensor performance, pos-
sibly causing improper spark control. Always use
the specified torque when installing the knock sen-
sors.
REMOVAL
4.7L High-Output Engine Only
The 2 knock sensors are bolted into the cylinder
block under the intake manifold (Fig. 22).
NOTE: The left sensor is identified by an identifica-
tion tag (LEFT). It is also identified by a larger bolt
head. The Powertrain Control Module (PCM) must
have and know the correct sensor left/right posi-
tions. Do not mix the sensor locations.
(1) Disconnect knock sensor dual pigtail harness
connector from engine wiring harness connector. This
connection is made near the right/rear of intake man-
ifold (Fig. 23).
(2) Remove intake manifold. Refer to Engine sec-
tion.
(3) Remove sensor mounting bolts (Fig. 22). Note
foam strip on bolt threads. This foam is used only to
retain the bolts to sensors for plant assembly. It is
not used as a sealant. Do not apply any adhesive,
sealant or thread locking compound to these bolts.
(4) Remove sensors from engine.
Fig. 22 KNOCK SENSOR LOCATION - 4.7L H.O.
1 - KNOCK SENSORS (2)
2 - MOUNTING BOLTS
3 - INTAKE MANIFOLD (CUTAWAY)
4 - PIGTAIL CONNECTOR
Fig. 23 KNOCK SENSOR ELEC. CONNECTOR - 4.7L
H.O.
1 - KNOCK SENSOR PIGTAIL HARNESS CONNECTOR
2 - ENGINE WIRING HARNESS
8I - 14 IGNITION CONTROLWJ
KNOCK SENSOR (Continued)

INSTALLATION
4.7L High-Output Engine Only
NOTE: The left sensor is identified by an identifica-
tion tag (LEFT). It is also identified by a larger bolt
head. The Powertrain Control Module (PCM) must
have and know the correct sensor left/right posi-
tions. Do not mix the sensor locations.
(1) Thoroughly clean knock sensor mounting holes.
(2) Install sensors (Fig. 22) into cylinder block.
NOTE: Over or under tightening the sensor mount-
ing bolts will affect knock sensor performance, pos-
sibly causing improper spark control. Always use
the specified torque when installing the knock sen-
sors. The torque for the knock senor bolt is rela-
tively light for an 8mm bolt.
NOTE: Note foam strip on bolt threads. This foam is
used only to retain the bolts to sensors for plant
assembly. It is not used as a sealant. Do not apply
any adhesive, sealant or thread locking compound
to these bolts.
(3) Install and tighten mounting bolts.Bolt
torque is critical.Refer to torque specification.
(4) Install intake manifold. Refer to Engine sec-
tion.
(5) Connect knock sensor pigtail wiring harness to
engine wiring harness near right / rear of intake
manifold (Fig. 23).
SPARK PLUG
DESCRIPTION
Both the 4.0L 6-cylinder and the 4.7L V-8 engine
use resistor type spark plugs. Standard 4.7L V-8
engines are equipped with ªfired in suppressor sealº
type spark plugs using a copper core ground elec-
trode. High-Output (H.O.) 4.7L V-8 engines are
equipped with unique plugs using a platinum rivet
located on the tip of the center electrode.
Because of the use of an aluminum cylinder head
on the 4.7L engine, spark plug torque is very critical.
To prevent possible pre-ignition and/or mechanical
engine damage, the correct type/heat range/number
spark plug must be used.Do not substitute any
other spark plug on the 4.7L H.O. engine. Seri-
ous engine damage may occur.
Plugs on both engines have resistance values rang-
ing from 6,000 to 20,000 ohms (when checked with at
least a 1000 volt spark plug tester).Do not use an
ohmmeter to check the resistance values of thespark plugs. Inaccurate readings will result.
Remove the spark plugs and examine them for
burned electrodes and fouled, cracked or broken por-
celain insulators. Keep plugs arranged in the order
in which they were removed from the engine. A sin-
gle plug displaying an abnormal condition indicates
that a problem exists in the corresponding cylinder.
Replace spark plugs at the intervals recommended in
Group O, Lubrication and Maintenance.
EXCEPT 4.7L H.O. ENGINE :Spark plugs that
have low mileage may be cleaned and reused if not
otherwise defective, carbon or oil fouled. Also refer to
Spark Plug Conditions.4.7L H.O. ENGINE :Never
clean spark plugs on the 4.7L H.O. engine. Damage
to the platinum rivet will result.
CAUTION: EXCEPT 4.7L H.O. ENGINE : Never use a
motorized wire wheel brush to clean the spark
plugs. Metallic deposits will remain on the spark
plug insulator and will cause plug misfire.
H.O. Gap Adjustment:If equipped with the 4.7L
H.O. engine, do not use a wire-type gapping tool as
damage to the platinum rivet on the center electrode
may occur. Use a tapered-type gauge (Fig. 24).
DIAGNOSIS AND TESTING - SPARK PLUG
CONDITIONS
NORMAL OPERATING
The few deposits present on the spark plug will
probably be light tan or slightly gray in color. This is
evident with most grades of commercial gasoline
Fig. 24 PLUG GAP - 4.7L H.O.
1 - TAPER GAUGE
WJIGNITION CONTROL 8I - 15
KNOCK SENSOR (Continued)

EMIC also uses several hard wired inputs in order to
perform its many functions. The EMIC module incor-
porates a blue-green digital Vacuum Fluorescent Dis-
play (VFD) for displaying odometer and trip
odometer information.
The EMIC houses six analog gauges and has pro-
visions for up to twenty indicators (Fig. 2). The
EMIC includes the following analog gauges:
²Coolant Temperature Gauge
²Fuel Gauge
²Oil Pressure Gauge
²Speedometer
²Tachometer
²Voltage Gauge
Some of the EMIC indicators are automatically
configured when the EMIC is connected to the vehi-
cle electrical system for compatibility with certain
optional equipment or equipment required for regula-
tory purposes in certain markets. While each EMIC
may have provisions for indicators to support every
available option, the configurable indicators will not
be functional in a vehicle that does not have the
equipment that an indicator supports. The EMIC
includes provisions for the following indicators (Fig.
2):
²Airbag Indicator (with Airbags only)
²Antilock Brake System (ABS) Indicator
²Brake Indicator
²Check Gauges Indicator
²Coolant Low Indicator (with Diesel Engine
only)
²Cruise Indicator
²Four-Wheel Drive Part Time Indicator
(with Selec-Trac NVG-242 Transfer Case only)
²Front Fog Lamp Indicator (with Front Fog
Lamps only)
²High Beam Indicator
²Low Fuel Indicator
²Malfunction Indicator Lamp (MIL)
²Overdrive-Off Indicator (except Diesel
Engine)
²Rear Fog Lamp Indicator (with Rear Fog
Lamps only)
²Seatbelt Indicator
²Sentry Key Immobilizer System (SKIS)
Indicator
²Transmission Overtemp Indicator (except
Diesel Engine)²Turn Signal (Right and Left) Indicators
²Wait-To-Start Indicator (with Diesel Engine
only)
²Water-In-Fuel Indicator (with Diesel Engine
only)
Many indicators in the EMIC are illuminated by a
dedicated Light Emitting Diode (LED) that is sol-
dered onto the EMIC electronic circuit board. The
LEDs are not available for service replacement and,
if damaged or faulty, the entire EMIC must be
replaced. Base cluster illumination is accomplished
by dimmable incandescent back lighting, which illu-
minates the gauges for visibility when the exterior
lighting is turned on. Premium cluster illumination
is accomplished by a dimmable electro-luminescent
lamp that is serviced only as a unit with the EMIC.
Each of the incandescent bulbs is secured by an inte-
gral bulb holder to the electronic circuit board from
the back of the cluster housing. The incandescent
bulb/bulb holder units are available for service
replacement.
Hard wired circuitry connects the EMIC to the
electrical system of the vehicle. These hard wired cir-
cuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained by
many different methods. These circuits may be con-
nected to each other, to the vehicle electrical system
and to the EMIC through the use of a combination of
soldered splices, splice block connectors, and many
different types of wire harness terminal connectors
and insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
The EMIC modules for this model are serviced only
as complete units. The EMIC module cannot be
adjusted or repaired. If a gauge, an LED indicator,
the VFD, the electronic circuit board, the circuit
board hardware, the cluster overlay, the electro-lumi-
nescent lamp (premium model only) or the EMIC
housing are damaged or faulty, the entire EMIC mod-
ule must be replaced. The cluster lens, hood and
mask unit and the individual incandescent lamp
bulbs with holders are available for service replace-
ment.
WJINSTRUMENT CLUSTER 8J - 3
INSTRUMENT CLUSTER (Continued)