2002 JEEP GRAND CHEROKEE body control

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Left Front Park/Turn Signal
Lamp (Except Built-Up-Export)BK At Lamp N/S
Left Front Side Marker Lamp
(Except Built-Up-Export)WT At Lamp N/S
Left Front Turn Signal Lamp
(Built-Up-Export)WT At Lamp N/S
Left Front Wheel Speed
SensorGY At Left Front Wheel Opening 4
Left Headlamp Leveling Motor
(Built-Up-Export)BK At Motor N/S
Left High Beam Headlamp BK At Lamp N/S
Left Instrument Panel Speaker WT At Speaker 19, 20
Left Liftgate Ajar Switch BK In Liftgate 38
Left Low Beam Headlamp GY At Lamp N/S
Left Multi-Function Switch WT On Steering Column 23
Left Rear Door Lock Motor/Ajar
SwitchBK In Left Rear Door 28
Left Rear Door Speaker WT In Left Rear Door 28
Left Rear Lamp Assembly BK At Lamp Assembly 37
Left Rear Wheel Speed Sensor GY Near Left Rear Wheel 33, 35
Left Remote Radio Switch BK At Switch in Steering Wheel N/S
Left Side Impact Sensor BK Left Body N/S
Left Side Repeater Lamp
(Built-Up-Export)BK On Left Front Fender 3, 4
Left Visor/Vanity Lamp BK At Lamp N/S
License Lamp No.1 BK At Lamp N/S
License Lamp No.2 BK At Lamp N/S
Liftgate Flip-Up Ajar Switch GY In Liftgate 38
Liftgate Flip-Up Push Button
SwitchBK In Liftgate N/S
Liftgate Flip-Up Release
SolenoidBK In Liftgate 38
Liftgate Lock Motor BK In Liftgate 38
Line Pressure Sensor (4.7L) BK Rear of Transmission N/S
Manifold Absolute Pressure
Sensor (4.0L)BK At Throttle Body 9
Manifold Absolute Pressure
Sensor (4.7L)BK Right Side of Engine 13
Manual Temperature Control -
C1 (MTC)WT Center of Instrument Panel N/S
Manual Temperature Control -
C2 (MTC)WT Center of Instrument Panel N/S
Mass Air Flow sensor (Diesel) BK Near T/O for G105 8
Mode Door Motor/Actuator
(AZC)BK Right Center of Instrument Panel N/S
WJ8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 7
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

JUNCTION BLOCK
DESCRIPTION
An electrical Junction Block (JB) is concealed
beneath the driver side of the instrument panel in
the passenger compartment of the vehicle (Fig. 3).
The JB combines the functions previously provided
by a separate fuseblock module and relay center. The
JB serves to simplify and centralize numerous elec-
trical components, as well as to distribute electrical
current to many of the accessory systems in the vehi-
cle. It also eliminates the need for numerous splice
connections. The JB houses up to thirty-three blade-
type mini fuses, up to two blade-type automatic
resetting circuit breakers, the electronic combination
flasher, the Daytime Running Lamp (DRL) module
(Canada only) and up to twelve International Stan-
dards Organization (ISO) relays (three standard-type
and nine micro-type). The JB also incorporates an
integral connector and mounting for the Body Con-
trol Module (BCM). The BCM is secured with four
screws directly to the dash panel side of the JB.
Refer toBody Control Modulein Electronic Con-
trol Modules for additional information covering the
BCM.
The molded plastic JB housing has integral mounts
that are secured with two screws and two snap
retainers to the instrument panel steering column
support bracket behind the instrument panel steer-ing column opening cover. The JB is concealed above
the molded plastic instrument panel fuse cover. Inte-
gral latches molded into the fuse cover secure it the
JB, the BCM and the 16-way data link connector tab
of the instrument panel steering column support
bracket. The fuse cover can be pulled downward to
disengage the latches and provide service access to
all of the fuses, relays and wire harness connectors of
the JB. The fuse cover has a fuse puller and spare
fuses secured to its upper surface. Refer toInstru-
ment Panel Fuse Coverin Body for additional ser-
vice information.
The JB unit cannot be repaired and is only ser-
viced as an assembly. If any internal circuit or the JB
housing is faulty or damaged, the entire JB unit
must be replaced. The BCM is available for separate
service replacement.
OPERATION
All of the circuits entering and leaving the Junc-
tion Block (JB) do so through up to five wire harness
connectors, which are connected to the JB through
integral connector receptacles molded into the JB
housing. Internal connection of all of the JB circuits
is accomplished by a printed circuit board. There are
also two separate wire harness connections to con-
nector receptacles that are integral to the BCM.
Refer toJunction Blockin Wiring Diagrams for
additional information and the location of complete
JB circuit diagrams.
REMOVAL
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT AND ISOLATE THE BATTERY NEGATIVE
(GROUND) CABLE, THEN WAIT TWO MINUTES FOR
THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE AIRBAG SYSTEM. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the fuse cover from the bottom of the
Junction Block (JB).
(3) Remove the steering column opening cover
from the instrument panel. Refer toSteering Col-
umn Opening Coverin Body for the location of
steering column opening cover removal procedures.
Fig. 3 Junction Block Location
1 - REAR LATCHES
2 - JUNCTION BLOCK AND BODY CONTROL MODULE UNIT
3 - INSTRUMENT PANEL FUSE COVER
4 - SIDE LATCH
5 - FRONT LATCHES
WJ8W-97 POWER DISTRIBUTION 8W - 97 - 5

(4) Reach behind the JB to disconnect the two
instrument panel wire harness connectors from the
Body Control Module (BCM) connector receptacles
located near the bottom of the JB (Fig. 4).
(5) Reach behind the JB to remove the screw that
secures the instrument panel wire harness bulkhead
connector to the connector receptacle located near the
top of the JB and disconnect the connector.
(6) Disconnect the fused B(+) and the IOD wire
harness connectors from the connector receptacles
located near the bottom of the JB (Fig. 5).
(7) Remove the screws that secure the right and
left body wire harness bulkhead connectors to the
connector receptacles located near the center of the
JB and disconnect the connectors.
(8) Remove the two screws that secure the JB to
the instrument panel steering column support
bracket (Fig. 6).
(9) To disengage the two snap clips that secure the
top of the JB to the instrument panel steering col-
umn support bracket, grasp the bottom of the junc-
tion block firmly with both hands and pull it
downward sharply.
(10) Remove the JB from the instrument panel
steering column support bracket.
INSTALLATION
NOTE: If the Junction Block (JB) is being replaced
with a new unit, be certain to transfer each of the
optional fuses, circuit breakers and relays from thefaulty JB to the proper cavities of the replacement
JB. Refer to Junction Block in Wiring Diagrams for
the location of complete circuit diagrams and cavity
assignments for the JB. The Body Control Module
(BCM) must also be transferred to the new JB.
Refer to Body Control Module in Electronic Control
Modules for the location of the BCM removal and
installation procedures.
(1)
Position the JB into its mounting location on the
instrument panel steering column support bracket.
(2) Align the snap clips at the top of the JB with
the mounting holes in the instrument panel steering
column support bracket.
(3) Grasp the bottom of the JB firmly with both
hands and push it upward sharply to engage the two
snap clips that secure the top of the JB to the instru-
ment panel steering column support bracket.
(4)
Install and tighten the two screws that secure the
JB to the instrument panel steering column support
bracket. Tighten the screws to 2.2 N´m (20 in. lbs.).
Fig. 4 Junction Block Connections
1 - SCREW
2 - JUNCTION BLOCK
3 - BULKHEAD CONNECTOR
4 - BODY CONTROL MODULE
5 - INSTRUMENT PANEL WIRE HARNESS CONNECTORS
Fig. 5 Junction Block Connections
1 - SNAP CLIPS
2 - SCREW
3 - CONNECTOR
4 - LEFT BODY WIRE HARNESS
5 - IOD CONNECTOR
6 - FUSED B+ CONNECTOR
7 - RIGHT BODY WIRE HARNESS
8 - SCREW
9 - CONNECTOR
10 - JUNCTION BLOCK
8W - 97 - 6 8W-97 POWER DISTRIBUTIONWJ
JUNCTION BLOCK (Continued)

PDC LOWER COVER INSTALLATION
(1) Align the PDC housing lower cover on the bot-
tom of the PDC.
(2) Evenly press the lower cover into place until
latches are fully engaged.
(3) Where the right headlamp and dash harness
enters the PDC, tape the harness securely to the
trough formation on the PDC lower cover.
(4) Install the PDC in its mounting location on the
battery support.
(5) Install the battery wire harness over the two
PDC B+ terminal studs. Torque the nuts to 11.3 N´m
(100 in. lbs.).
(6) Install the battery. Refer to Battery System for
the procedure.
(7) Install the PDC cover.
INSTALLATION
The Power Distribution Center (PDC) main hous-
ing unit, the PDC fuse wedges and the PDC bus bars
cannot be repaired and are only serviced as a unit
with the right headlamp and dash wire harness. If
the PDC main housing unit, the fuse wedges or the
bus bars are faulty or damaged, the entire PDC and
right headlamp and dash wire harness unit must be
replaced.
(1) Position the PDC and the right headlamp and
dash wire harness unit in the engine compartment.
(2) Engage the PDC housing mounts with the
stanchions of the battery support and push the unit
downward until the mount latches fully engage the
mounting tabs on the stanchions.
(3) Install the two-holed eyelet of the battery wire
harness PDC take outs onto the two PDC B(+) termi-
nal studs.
(4) Install and tighten the nuts that secure the
eyelet of the battery wire harness PDC take outs to
the B(+) terminal studs. Tighten the nuts to 11.3
N´m (100 in. lbs.).
(5) Engage each of the retainers that secure the
right headlamp and dash wire harness to the vehicle
body and chassis components. Refer toConnector
Locationsin Wiring Diagrams for the location of
more information on the right headlamp and dash
wire harness retainer locations.
(6) Install all of the fasteners that secure each of
the right headlamp and dash wire harness ground
eyelets to the vehicle body and chassis components.
Refer toConnector Locationsin Wiring Diagrams
for the location of more information on the ground
eyelet locations.
(7) Reconnect each of the right headlamp and dash
wire harness connectors. Refer toConnector Loca-
tionsin Wiring Diagrams for the location of more
information on the right headlamp and dash wire
harness connector locations. For connectors securedwith screws, tighten the screws to 4.3 N´m (38 in.
lbs.).
(8) Reconnect the battery negative cable.
POWER OUTLET
DESCRIPTION - FRONT POWER OUTLET
An accessory power outlet is standard equipment
on this model. The power outlet is installed in the
instrument panel center lower bezel, which is located
near the bottom of the instrument panel center stack
area, below the heater and air conditioner controls.
The power outlet base is secured by a snap fit within
the center lower bezel. A hinged door with an over-
center spring flips closed to conceal and protect the
power outlet base when the power outlet is not being
used, and flips open below the center lower bezel
while the power outlet is in use.
The power outlet receptacle unit and the power
outlet door are each available for service replace-
ment.
OPERATION - FRONT POWER OUTLET
The power outlet base or receptacle shell is con-
nected to ground, and an insulated contact in the
bottom of the shell is connected to battery current.
The power outlet receives battery voltage from a fuse
in the junction block at all times.
While the power outlet is very similar to a cigar
lighter base unit, it does not include the two small
spring-clip retainers inside the bottom of the recepta-
cle shell that are used to secure the cigar lighter
heating element to the insulated contact.
DIAGNOSIS AND TESTING - POWER OUTLET
For complete circuit diagrams, refer toHorn/Ci-
gar Lighter/Power Outletin Wiring Diagrams.
WARNING: REFER TO RESTRAINTS BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
(1) Check the fused B(+) fuse in the junction block.
If OK, go to Step 2. If not OK, repair the shorted cir-
cuit or component as required and replace the faulty
fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the junction block. If OK, go to Step 3. If not OK,
repair the open fused B(+) circuit to the Power Dis-
tribution Center (PDC) fuse as required.
(3) Open the power outlet door. Check for continu-
ity between the inside circumference of the power
8W - 97 - 12 8W-97 POWER DISTRIBUTIONWJ
POWER DISTRIBUTION CENTER (Continued)

ground at all times. If not OK, repair the open
ground circuit to ground as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the steering column opening cover
from the instrument panel. Refer toSteering Col-
umn Opening Coverin Body for the procedure.
(3) The power outlet / cigar lighter relay is located
on the left side of the combination flasher in the
junction block.
(4) Remove the power outlet / cigar lighter relay
from the junction block.
INSTALLATION
(1) Position the power outlet / cigar lighter relay in
the proper receptacle in the junction block.
(2) Align the power outlet / cigar lighter relay ter-
minals with the terminal cavities in the junction
block receptacle.
(3) Push in firmly on the power outlet / cigar
lighter relay until the terminals are fully seated in
the terminal cavities in the junction block receptacle.
(4) Install the steering column opening cover onto
the instrument panel. Refer toSteering Column
Opening Coverin Body for the procedure.
(5) Reconnect the battery negative cable.
IOD WIRE HARNESS
CONNECTOR
DESCRIPTION
All vehicles are equipped with an Ignition-Off
Draw (IOD) connector that is located in a molded
connector receptacle on the lower rear surface of the
Junction Block (JB) housing (Fig. 17). The JB is con-
cealed above the molded plastic instrument panel
fuse cover. Integral latches molded into the fuse
cover secure it the JB, the Body Control Module
(BCM) and the 16-way data link connector tab of the
instrument panel steering column support bracket.
The fuse cover can be pulled downward to disengage
the latches and provide service access to all of the
fuses, relays and wire harness connectors of the JB.
Refer toInstrument Panel Fuse Coverin the
index of this service manual for the location of addi-
tional service information covering the fuse cover.
OPERATION
The term ignition-off draw identifies a normal con-
dition where power is being drained from the battery
with the ignition switch in the Off position. The IOD
connector feeds the memory and sleep mode func-
tions for some of the electronic modules in the vehicleas well as various other accessories that require bat-
tery current when the ignition switch is in the Off
position, including the clock.
The IOD connector can be used by the vehicle
owner as a convenient means of reducing battery
depletion when a vehicle is to be stored for periods
not to exceed about twenty days (short-term storage).
Simply disconnect the IOD connector from the JB
receptacle. However, it must be remembered that dis-
connecting the IOD connector will not eliminate IOD,
but only reduce this normal condition. When a vehi-
cle will not be used for more than twenty days, but
less than thirty days, remove the IOD fuse from the
Power Distribution Center (PDC). If a vehicle will be
stored for more than about thirty days, the battery
negative cable should be disconnected to eliminate
normal IOD; and, the battery should be tested and
recharged at regular intervals during the vehicle
storage period to prevent the battery from becoming
discharged or damaged. Refer toIgnition-Off Draw
Fig. 17 Ignition-Off Draw Connector
1 - SNAP CLIPS
2 - SCREW
3 - CONNECTOR
4 - LEFT BODY WIRE HARNESS
5 - IOD CONNECTOR
6 - FUSED B+ CONNECTOR
7 - RIGHT BODY WIRE HARNESS
8 - SCREW
9 - CONNECTOR
10 - JUNCTION BLOCK
WJ8W-97 POWER DISTRIBUTION 8W - 97 - 15
POWER OUTLET RELAY (Continued)

FuseandBatteryin the index in this service man-
ual for the location of additional service information
covering the ignition-off draw fuse and the battery.
FUSE COVER
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Pull down on the rear edge (nearest the rear of
the vehicle) of the instrument panel fuse cover until
the rear latches unsnap from the tabs on the lower
junction block housing and the side latch unsnaps
from the tab on the instrument panel steering col-
umn support bracket outboard of the 16-way data
link connector (Fig. 18).
(3) Move the instrument panel fuse cover towards
the front of the vehicle to disengage the front latches
from the mounting slots in the lower housing of the
body control module.
(4) Remove the fuse cover from under the instru-
ment panel.
INSTALLATION
(1) Position the two front latches of the instrument
panel fuse cover within the two locator channel for-
mations on the bottom of the body control module
housing (Fig. 19).
(2) While applying a slight upward pressure to the
instrument panel fuse cover over the front latches,
slowly slide the front latches through the locator
channels toward the front of the vehicle until thelatches exit the front of the locator channels. This
will locate the front latches at the mounting slots in
the lower housing of the body control module.
(3) Apply a slight rearward pressure on the instru-
ment panel fuse cover to engage the front latches in
the mounting slots in the lower housing of the body
control module.
(4) Swing the rear edge (nearest the rear of the
vehicle) of the instrument panel fuse cover up toward
the junction block.
(5) Press firmly upward on the instrument panel
fuse cover over the rear latches until the latches
snap into place over the tabs on the lower edge of the
junction block housing.
(6) Press firmly upward on the 16-way data link
connector cover formation of the instrument panel
fuse cover until the side latch snaps into place over
the tab on the outboard side of the instrument panel
steering column support bracket.
(7) Reconnect the battery negative cable.
REAR POWER OUTLET
DESCRIPTION - REAR POWER OUTLET
A rear accessory power outlet is optional equip-
ment on this model. The rear power outlet is
installed in the lower right quarter trim panel near
the right liftgate opening pillar in the cargo area of
Fig. 18 Instrument Panel Fuse Cover Remove/Install
1 - REAR LATCHES
2 - JUNCTION BLOCK AND BODY CONTROL MODULE UNIT
3 - INSTRUMENT PANEL FUSE COVER
4 - SIDE LATCH
5 - FRONT LATCHES
Fig. 19 Instrument Panel Fuse Cover Locator
Channels
1 - JUNCTION BLOCK
2 - SCREWS (4)
3 - BODY CONTROL MODULE
4 - FUSE COVER LOCATOR CHANNELS
5 - FUSE COVER MOUNTING SLOTS
6 - INSTRUMENT PANEL WIRE HARNESS CONNECTORS
8W - 97 - 16 8W-97 POWER DISTRIBUTIONWJ
IOD WIRE HARNESS CONNECTOR (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
3. Worn or incorrect gapped spark
plugs3. Clean plugs and set gap. (Refer to
8 - ELECTRICAL/IGNITION
CONTROL/SPARK PLUG -
CLEANING).
4. Dirt or water in fuel system 4. Clean system and replace fuel
filter
5. Faulty fuel pump 5. Install new fuel pump
6. Incorrect valve timing 6. Correct valve timing
7. Blown cylinder head gasket 7. Install new cylinder head gasket
8. Low compression 8. Test cylinder compression. (Refer
to 9 - ENGINE - DIAGNOSIS AND
TESTING).
9. Burned, warped, or pitted valves 9. Install/Reface valves as necessary
10. Plugged or restricted exhaust
system10. Install new parts as necessary
11. Faulty ignition coil rail 11. Test and replace, as necessary.
(Refer to 8 - ELECTRICAL/IGNITION
CONTROL/COIL RAIL - REMOVAL).
ENGINE STALLS OR ROUGH
IDLE1. Carbon build-up on throttle plate 1. Remove throttle body and
de-carbon. (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/
THROTTLE BODY - REMOVAL) for
correct procedure.
2. Engine idle speed too low 2. Check Idle Air Control circuit.
3. Worn or incorrectly gapped spark
plugs3. Replace or clean and re-gap spark
plugs. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING)
4. Faulty coil rail 4. Test and replace, if necessary.
(Refer to 8 - ELECTRICAL/IGNITION
CONTROL/COIL RAIL - REMOVAL)
5. Intake manifold vacuum leak 5. Inspect intake manifold gasket and
vacuum hoses. Replace if necessary.
(Refer to 9 - ENGINE/MANIFOLDS/
INTAKE MANIFOLD - DIAGNOSIS
AND TESTING).
ENGINE MISSES ON
ACCELERATION1. Worn or incorrectly gapped spark
plugs1. Replace spark plugs or clean and
set gap.
2. Spark plug cables defective or
crossed2. Replace spark plug cables.
3. Dirt in fuel system 3. Clean fuel system
4. Burned, warped or pitted valves 4. Install new valves
5. Faulty coil rail 5. Test and replace as necessary.
(Refer to 8 - ELECTRICAL/IGNITION
CONTROL/COIL RAIL - REMOVAL)
WJENGINE - 4.0L 9 - 5
ENGINE - 4.0L (Continued)

DIAGNOSIS AND TESTINGÐCYLINDER
COMPRESSION PRESSURE
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise, the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Clean the spark plug recesses with compressed
air.
(2) Remove the spark plugs (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/SPARK PLUG -
REMOVAL).
(3) Secure the throttle in the wide-open position.
(4) Disconnect the ignition coil.
(5) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(6) Record the compression pressure on the third
revolution. Continue the test for the remaining cylin-
ders.
(Refer to 9 - ENGINE - SPECIFICATIONS) for the
correct engine compression pressures.
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
²Exhaust and intake valve leaks (improper seat-
ing)
²Leaks between adjacent cylinders or into water
jacket²Any causes for combustion/compression pressure
loss
WARNING: DO NOT REMOVE THE RADIATOR CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM HOT COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the radiator cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn OFF the
engine.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
Calibrate the tester according to the manufactur-
er's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1,379
kPa (200 psi) maximum and 552 kPa (80 psi) recom-
mended.
Perform the test procedure on each cylinder accord-
ing to the tester manufacturer's instructions. While
testing, listen for pressurized air escaping through
the throttle body, tailpipe or oil filler cap opening.
Check for bubbles in the radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder CYLINDER COMBUSTION
PRESSURE LEAKAGE DIAGNOSIS CHART .
CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
AIR ESCAPES THROUGH
THROTTLE BODYIntake valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
TAILPIPEExhaust valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
RADIATORHead gasket leaking or cracked
cylinder head or blockRemove cylinder head and inspect.
Replace defective part
MORE THAN 50% LEAKAGE
FROM ADJACENT CYLINDERSHead gasket leaking or crack in
cylinder head or block between
adjacent cylindersRemove cylinder head and inspect.
Replace gasket, head, or block as
necessary
MORE THAN 25% LEAKAGE AND
AIR ESCAPES THROUGH OIL
FILLER CAP OPENING ONLYStuck or broken piston rings;
cracked piston; worn rings and/or
cylinder wallInspect for broken rings or piston.
Measure ring gap and cylinder
diameter, taper and out-of-round.
Replace defective part as necessary
9 - 8 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)