2002 JEEP GRAND CHEROKEE Wheels

SPARE TIRE
DESCRIPTION - SPARE / TEMPORARY TIRE
The temporary spare tire is designed for emer-
gency use only. The original tire should be repaired
or replaced at the first opportunity, then reinstalled.
Do not exceed speeds of 50 M.P.H. when using the
temporary spare tire. Refer to Owner's Manual for
complete details.
WHEELS
DESCRIPTION
The rim size is on the vehicle safety certification
label located on the drivers door shut face. The size
of the rim is determined by the drivetrain package.
Original equipment wheels/rims are designed for
operation up to the specified maximum vehicle capac-
ity.
All models use stamped steel, cast aluminum or
forged aluminum wheels. Every wheel has raised sec-
tions between the rim flanges and rim drop well
called safety humps (Fig. 18) .
Initial inflation of the tire forces the bead over
these raised sections. In case of rapid loss of air pres-
sure, the raised sections help hold the tire on the
wheel.
The wheel studs and nuts are designed for specific
applications. All aluminum and some steel wheels
have wheel stud nuts with an enlarged nose. This
enlarged nose is necessary to ensure proper retentionof the wheels. Do not use replacement studs or nuts
with a different design or lesser quality.
DIAGNOSIS AND TESTING - WHEEL
INSPECTION
Inspect wheels for:
²Excessive run out
²Dents or cracks
²Damaged wheel lug nut holes
²Air Leaks from any area or surface of the rim
NOTE: Do not attempt to repair a wheel by hammer-
ing, heating or welding.
If a wheel is damaged an original equipment
replacement wheel should be used. When obtaining
replacement wheels, they should be equivalent in
load carrying capacity. The diameter, width, offset,
pilot hole and bolt circle of the wheel should be the
same as the original wheel.
WARNING: FAILURE TO USE EQUIVALENT
REPLACEMENT WHEELS MAY ADVERSELY
AFFECT THE SAFETY AND HANDLING OF THE
VEHICLE. USED WHEELS ARE NOT RECOM-
MENDED. THE SERVICE HISTORY OF THE WHEEL
MAY HAVE INCLUDED SEVERE TREATMENT OR
VERY HIGH MILEAGE. THE RIM COULD FAIL WITH-
OUT WARNING.
STANDARD PROCEDURE - WHEEL
REPLACEMENT
The wheel studs and nuts are designed for specific
applications. They must be replaced with equivalent
parts. Do not use replacement parts of lesser quality
or a substitute design. All aluminum and some steel
wheels have wheel stud nuts which feature an
enlarged nose. This enlarged nose is necessary to
ensure proper retention of the aluminum wheels.
NOTE: Do not use chrome plated lug nuts with
chrome plated wheels.
Before installing the wheel, be sure to remove any
build up of corrosion on the wheel mounting surfaces.
Ensure wheels are installed with good metal-to-metal
contact. Improper installation could cause loosening
of wheel nuts. This could affect the safety and han-
dling of your vehicle.
To install the wheel, first position it properly on
the mounting surface. All wheel nuts should then be
tightened just snug. Gradually tighten them in
sequence to the proper torque specification.Never
use oil or grease on studs or nuts.
Wheels must be replaced if they have:
²Excessive runout
Fig. 18 Safety Rim
1 - FLANGE
2 - RIDGE
3 - WELL
22 - 10 TIRES/WHEELSWJ

²Bent or dented
²Leak air through welds
²Have damaged bolt holes
Wheel repairs employing hammering, heating, or
welding are not allowed.
Original equipment wheels are available through
your dealer. Replacement wheels from any other
source should be equivalent in:
²Load carrying capacity
²Diameter
²Width²Offset
²Mounting configuration
Failure to use equivalent replacement wheels may
affect the safety and handling of your vehicle.
Replacement withusedwheels is not recommended.
Their service history may have included severe treat-
ment.
SPECIFICATIONS
TORQUE CHART
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Lug Nut
1/2 X 20 with 60É Cone115-150 85-115 Ð
STUDS
REMOVAL
CAUTION: Do not use a hammer to remove wheel
studs.
(1) Raise and support vehicle.
(2) Remove wheel and tire assembly.
(3) Remove brake caliper, caliper adapter and
rotor,(Refer to 5 - BRAKES/HYDRAULIC/MECHAN-
ICAL/ROTORS - REMOVAL).
(4) Remove stud from hub with Remover C-4150A
(Fig. 19).
INSTALLATION
CAUTION: Do not use a hammer to remove wheel
studs.
(1) Install the new stud into the hub flange.
(2) Install the three washers onto the stud, then
install the lug nut with the flat side of the nut
against the washers.
(3) Tighten the lug nut until the stud is pulled
into the hub flange. Verify that the stud is properly
seated into the flange.
(4) Remove the lug nut and washers.
(5) Install the brake rotor, caliper adapter, and
caliper,(Refer to 5 - BRAKES/HYDRAULIC/ME-
CHANICAL/DISC BRAKE CALIPERS - INSTALLA-
TION).(6) Install the wheel and tire assembly, use new
lug nut on stud or studs that were replaced.
(7) Remove the support and lower vehicle.Fig. 19 Wheel Stud Removal
1 - REMOVER
2 - WHEEL STUD
WJTIRES/WHEELS 22 - 11
WHEELS (Continued)

TIRE PRESSURE MONITORING
DESCRIPTION
The EVIC will monitor the tire pressure signals
from the five tire sensors and determine if any tire
has gone below the low pressure threshold or raised
above the high pressure threshold. Refer to the table
below.
LOW TIRE PRESSURE THRESHOLDS
SYSTEM STATUS
INDICATORTIRE PRESSURE
ON 179 kPa (26 PSI)
OFF 214 kPa (31 PSI)
HIGH TIRE PRESSURE THRESHOLDS
SYSTEM STATUS
INDICATORTIRE PRESSURE
ON 310 kPa (45 PSI)
OFF 276 kPa (40 PSI)
The Remote Tire Pressure Monitors (RTPM) are
not internally serviceable. For a Sensor Failure or
Low Battery fault, the RTPM must be replaced.
OPERATION
If equipped with the Tire Pressure Monitoring Sys-
tem, each of the vehicle's five wheels will have a
valve stem with a pressure sensor and radio trans-
mitter built in. Signals from the tire pressure sensors
are received and interpreted by the Electronic Vehi-
cle Information Center (EVIC). A sensor in a
mounted wheel will broadcast its detected pressure
once per minute when the vehicle is moving faster
than 40 km/h (25 mph). The spare tire sensor will
broadcast once every hour. Each sensor's broadcast is
uniquely coded so that the EVIC can determine loca-
tion. The individual tire pressures can be displayed
graphically on the EVIC
DIAGNOSIS AND TESTING - TIRE PRESSURE
MONITORING SYSTEM
All Tire Pressure Monitoring System Faults are
specific to one location. If a9BATTERY LOW9or
9SENSOR FAILURE9fault is detected, the location
will be displayed. The appropriate sensor/transmitter
can then be replaced. If a single sensor/transmitter
cannot be detected by the EVIC, replace that sensor
transmitter. If none of the sensors/transmitters can
be detected, refer to symptoms in the EVIC section.
For additional system description and diagnosis,
refer to Tire Pressure Monitoring in the Body Diag-
nostic manual.
SENSOR
REMOVAL - TIRE PRESSURE SENSOR/
TRANSMITTER
(1) Remove the tire/wheel from the vehicle.
CAUTION: When removing the stick on balancing
weights from the wheel, do not use an abrasive
cleaner or a cleaner which will damage the protec-
tive finish on the wheel.
(2) Remove the balancing weights from the wheel.
NOTE: The cap used on this valve stem contains an
O-ring seal to prevent contamination and moisture
from entering the valve stem. Retain this valve stem
cap for re-use. Do not substitute a regular valve
stem cap in its place.
(3) Remove the cap from the valve stem.
NOTE: The valve stem used on this vehicle is made
of aluminum and the core is nickel plated brass.
The original valve stem core must be reinstalled
and not substituted for a valve stem core made of a
different material. This is required to prevent corro-
sion in the valve stem caused by the different met-
als.
(4) Using the appropriate tool, remove the core
from the valve stem (Fig. 20).
(5) Let the tire fully deflate.
Fig. 20 REMOVING VALVE STEM CORE - TYPICAL
1 - WHEEL
2 - VALVE STEM
3 - TIRE
4 - VALVE STEM CORE TOOL
22 - 12 TIRES/WHEELSWJ

CAUTION: The pressure transmitter must be
removed from the wheel and dropped into the tire
prior to breaking the bead and dismounting the tire.
Failure to do this will greatly increase the risk of
damaging the pressure transducer when servicing
the tire.
(6) Remove nut mounting valve stem of pressure
sensor/transmitter to the wheel (Fig. 21). Drop sen-
sor/transmitter into tire.
CAUTION: When breaking the top and bottom bead
of the tire off the wheel, care must be used so the
bead breaking mechanism on the tire changer does
not damage the wheel. This includes the surface of
the wheel flange on the inside of the wheel.
(7) Using the tire changer manufacturers proce-
dure, first break down the upper bead of the tire.
Then break down the bottom bead of the tire.
CAUTION: When dismounting the upper tire bead
from the wheel, the proper procedure must be used.
Not using the proper procedure will result in dam-
age to the wheel and tire.(8) Dismount the upper bead of the tire from the
wheel.The upper bead must be fully dis-
mounted from the wheel to remove the tire
pressure transmitter from the inside of the tire.
The bottom bead of the tire does not need to be
removed from the wheel.
(9) Pull upward on the tire (Fig. 22). Reach into
the tire and remove the pressure sensor/transmitter
from inside the tire.
INSTALLATION - TIRE PRESSURE SENSOR/
TRANSMITTER
NOTE: When installing the tire pressure sensor/
transmitter, inspect the sealing O-ring at the bottom
of the valve stem for any sign of damage or deteri-
oration. Replace O-ring if necessary, before install-
ing the pressure transmitter on the wheel. Also, be
sure the surface of the wheel that the O-ring seals
against is clean and not damaged.
Fig. 21 VALVE STEM/PRESSURE TRANSMITTER -
TYPICAL
1 - NUT
2 - WHEEL
3 - TIRE
4 - VALVE STEM
Fig. 22 PRESSURE TRANSMITTER REMOVAL -
TYPICAL
1 - TIRE
2 - WHEEL
3 - PRESSURE TRANSMITTER
WJTIRES/WHEELS 22 - 13
SENSOR (Continued)

(1) Install the tire pressure sensor/transmitter on
the wheel (Fig. 23).
(2) Tighten the tire pressure sensor/transmitter
mounting nut to a torque of 11 N´m (97 in. lbs.) (Fig.
24). When tightening the sensor/transmitter nut,
hold the transmitter so it does not rotate. If the sen-
sor/transmitter rotates so the top edge is not level
with the wheel (Fig. 25), damage to the transmitter
will occur when mounting the tire. If the top edge of
the transmitter is not level with the wheel, it can be
rotated into position by lightly tapping it with your
hand.
CAUTION: When mounting the upper bead of the
extended mobility tire, the proper procedure must
be used. Not using the proper procedure will result
in damage to the wheel and tire.
(3) Mount the upper bead of the tire on the wheel.
(4) Install the original or an OEM replacement
valve stem cap on the valve stem.
(5) Using a soap solution, check that no air leak is
present where the valve stem mounts to the wheel.
(6) Balance the tire/wheel assembly using the cor-
rect procedure for using wheel flange mount and
stick-on wheel weights. For balancing information
and wheel weight positioning, (Refer to 22 - TIRES/
WHEELS - STANDARD PROCEDURE).
(7) Install the tire/wheel on the vehicle (Refer to
22 - TIRES/WHEELS - STANDARD PROCEDURE).
(8) Program the identification code for the new tire
pressure sensor/transmitter into the TPM module.(9) Verify that the TPM module has been pro-
grammed with the identification code from the new
tire pressure sensor/transmitter Refer to the appropi-
ate electrical section. If the identification code and
tire pressure thresholds from the new tire pressure
transmitter are present in the receivers memory the
new tire pressure transmitter has been correctly pro-
grammed to the receiver.
Fig. 23 TIRE PRESSURE SENSOR/TRANSMITTER -
TYPICAL
1 - WHEEL
2 - TIRE PRESSURE TRANSMITTER
Fig. 24 TIGHTENING SENSOR/TRANSDUCER -
TYPICAL
1 - TORQUE WRENCH
2 - WHEN TORQUING TRANSMITTER MOUNTING NUT DO NOT
LET THIS END OF TRANSMITTER ROTATE AWAY FROM THE
WHEEL
3 - WHEEL
4 - TIRE PRESSURE TRANSMITTER
Fig. 25 CORRECTLY POSITIONED SENSOR/TRAN -
TYPICAL
1 - THE TOP EDGES OF THE TIRE PRESSURE SENSOR/
TRANSMITTER MUST BE FLUSH WITH THE WHEEL HERE
2 - WHEEL
3 - TIRE PRESSURE SENSOR/TRANSMITTER
22 - 14 TIRES/WHEELSWJ
SENSOR (Continued)

INSTRUMENT PANEL SYSTEM
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.
NOTE: Before starting this procedure, be certain to
turn the steering wheel until the front wheels are in
the straight-ahead position.
(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 to the studs on the dash panel near the
windshield fence line (Fig. 1).
(5) Remove the scuff plates from the right and left
front door sills. (Refer to 23 - BODY/INTERIOR/
DOOR SILL SCUFF PLATE - REMOVAL).
(6) Remove the trim panels from the right and left
inner cowl sides. (Refer to 23 - BODY/INTERIOR/
COWL TRIM - REMOVAL).
(7) Remove the console from the floor panel trans-
mission tunnel. (Refer to 23 - BODY/INTERIOR/
FLOOR CONSOLE - REMOVAL).
(8) Remove the fuse cover from the Junction Block
(JB). (Refer to 8 - ELECTRICAL/POWER DISTRIBU-
TION/FUSE COVER - REMOVAL).
(9) Remove the cluster bezel from the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
CLUSTER BEZEL - 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) Remove the steering column bracket from the
instrument panel steering column support bracket.
(Refer to 23 - BODY/INSTRUMENT PANEL/IP
STEERING COLUMN BRACKET - REMOVAL).
Fig. 1 Instrument Panel to Dash Panel Mounting
1 - STUD (4)
2 - NUT (4)3 - INSTRUMENT PANEL
4 - DASH PANEL
WJINSTRUMENT PANEL SYSTEM 23 - 37

A/C COMPRESSOR CLUTCH
DESCRIPTION
The compressor clutch assembly consists of a sta-
tionary electromagnetic coil, a hub bearing and pul-
ley assembly, and a clutch plate (Fig. 4). The
electromagnetic coil unit and the hub bearing and
pulley assembly are each retained on the nose of the
compressor front housing with snap rings. The clutch
plate is keyed to the compressor shaft and secured
with a bolt.
OPERATION
The compressor clutch components provide the
means to engage and disengage the compressor from
the engine serpentine accessory drive belt. When the
clutch coil is energized, it magnetically draws the
clutch into contact with the pulley and drives the
compressor shaft. When the coil is not energized, the
pulley freewheels on the clutch hub bearing, which is
part of the pulley. The compressor clutch and coil are
the only serviced parts on the compressor.
The compressor clutch engagement is controlled by
several components: the a/c switch on the a/c heater
control panel, the Automatic Zone Control (AZC) con-
trol module (if the vehicle is so equipped), the evap-
orator probe, the a/c high pressure transducer, the
a/c compressor clutch relay, the body control module
(BCM) and the Powertrain Control Module (PCM).
The PCM may delay compressor clutch engagement
for up to thirty seconds. Refer to Electronic Control
Modules for more information on the PCM controls.
DIAGNOSIS AND TESTING - COMPRESSOR
CLUTCH COIL
For circuit descriptions and diagrams, refer to the
appropriate wiring diagrams. The battery must be
fully-charged before performing the following tests.
Refer to Battery for more information.
(1) Connect an ammeter (0 to 10 ampere scale) in
series with the clutch coil terminal. Use a voltmeter
(0 to 20 volt scale) with clip-type leads for measuring
the voltage across the battery and the compressor
clutch coil.
(2) With the a/c heater mode control switch in any
a/c mode, the a/c heater control a/c switch in the ON
position, and the blower motor switch in the lowest
speed position, start the engine and run it at normal
idle.
(3) The compressor clutch coil voltage should read
within 0.2 volts of the battery voltage. If there is
voltage at the clutch coil, but the reading is not
within 0.2 volts of the battery voltage, test the clutch
coil feed circuit for excessive voltage drop and repair
as required. If there is no voltage reading at the
clutch coil, use a DRBIIItscan tool and the appro-
priate diagnostic information for testing of the com-
pressor clutch circuit. The following components
must be checked and repaired as required before you
can complete testing of the clutch coil:
²Fuses in the junction block and the Power Dis-
tribution Center (PDC)
²A/C heater mode control switch
²A/C compressor clutch relay
²A/C high pressure transducer
²A/C evaporator probe
²Powertrain Control Module (PCM)
²Body Control Module (BCM)
(4) The compressor clutch coil is acceptable if the
current draw measured at the clutch coil is 2.0 to 3.9
amperes with the electrical system voltage at 11.5 to
12.5 volts. This should only be checked with the work
area temperature at 21É C (70É F). If system voltage
is more than 12.5 volts, add electrical loads by turn-
ing on electrical accessories until the system voltage
drops below 12.5 volts.
(a) If the clutch coil current reading is four
amperes or more, the coil is shorted and should be
replaced.
(b) If the clutch coil current reading is zero, the
coil is open and should be replaced.
Fig. 4 COMPRESSOR CLUTCH - TYPICAL
1 - CLUTCH PLATE
2 - SHAFT KEY
3 - PULLEY
4 - COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
WJCONTROLS 24 - 13

VISCOUS HEATER
DESCRIPTION
DESCRIPTION
The diesel engine has an engine mounted mechan-
ical device called a Viscous Heater that is used to
heat the coolant coming from the engine to the
heater core. The Viscous Heater is driven by the
engine fan belt and has a electro-mechanical clutch
which is controlled by the HVAC control unit.
DESCRIPTION - VISCOUS HEATER CLUTCH
The basic viscous heater clutch assembly consists
of a stationary electromagnetic coil, a hub bearing
and pulley assembly and a clutch plate. The electro-
magnetic coil unit and the hub bearing and pulley
assembly are each retained on the nose of the com-
pressor front housing with snap rings (Fig. 17). The
clutch plate is keyed to the viscous heater shaft and
secured with a nut. These components provide the
means to engage and disengage the viscous heater
from the engine accessory drive belt.
OPERATION
OPERATION - VISCOUS HEATER
The Viscous Heater is driven by the engine fan
belt. The Viscous Heater has an electro-mechanical
clutch that receives a signal from the HVAC control
head and the Viscous Heater controller that ener-
gizes and engages the clutch. Once engaged theclutch allows the Viscous Heater to increase the tem-
perature of the coolant flowing to the heater core,
which provides heat the passenger compartment
quicker than normal engines without the Viscous
Heater. The Viscous Heater generates heat by means
of friction which heats a special Silicon Oil within its
housing which is then transferred to the engine cool-
ant when the coolant passes over fins within the
pump. Please note that the coolant is isolated from
the silicon oil within the pump housing. When
demand for passenger compartment heat decreases
the Viscous Heater clutch will receive an input from
the Viscous heater controller to disengage.
OPERATION - VISCOUS HEATER CLUTCH
When the clutch coil is energized, it magnetically
draws the clutch into contact with the pulley and
drives the viscous heater shaft. When the coil is not
energized the pulley freewheels on the clutch hub
bearing, which is part of the pulley. The viscous
heater clutch and coil are the only serviced parts on
the viscous heater assembly. If the viscous heater is
inoperative or damaged the entire assembly must be
replaced. The viscous heater clutch engagement is
controlled by several components: the viscous heater
controller, the engine powertrain control module and
the HVAC control head.
REMOVAL
REMOVAL - VISCOUS HEATER
(1) Drain the engine coolant(Refer to 7 - COOL-
ING/ENGINE - STANDARD PROCEDURE).
(2) Remove the engine accessory drive belt(Refer to
7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(3) Remove the heater hose clamps at the Viscous
Heater.
(4) Remove the heater hoses from the Viscous
Heater.
(5) Unplug the Viscous Heater clutch electrical
connector.
(6) Remove the bolts holding the Viscous Heater to
the mounting bracket.
(7) Remove the Viscous Heater from the vehicle.
REMOVAL - VISCOUS HEATER CLUTCH
(1) The viscous heater clutch can be serviced in
the vehicle and the cooling system does not have to
be drained.
(2) Disconnect and isolate the battery negative
cable.
(3) Remove the serpentine drive belt(Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
Fig. 17 CLUTCH ASSEMBLY- typical
1 - CLUTCH PLATE
2 - SHAFT KEY
3 - PULLEY
4 - COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
24 - 76 PLUMBINGWJ