2002 JEEP GRAND CHEROKEE Control

POSITION SENSOR
DESCRIPTION
The transfer case position sensor (Fig. 95) is an
electronic device whose output can be interpreted to
indicate the transfer case's current operating mode.
The sensor consists of a five position, resistive multi-
plexed circuit which returns a specific resistance
value to the Powertrain Control Module (PCM) for
each transfer case operating mode. The sensor is
located on the top of the transfer case, just left of the
transfer case centerline and rides against the sector
plate roostercomb. The PCM supplies 5VDC (+/-
0.5V) to the sensor and monitors the return voltage
to determine the sector plate, and therefore the
transfer case, position.
OPERATION
During normal vehicle operation, the Powertrain
Control Module (PCM) monitors the transfer case
position sensor return voltage to determine the oper-
ating mode of the transfer case. Refer to the Operat-
ing Mode Versus Resistance table for the correct
resistance for each position (Fig. 96).
OPERATING MODE VERSUS RESISTANCE
SENSOR POSITION OPERATING MODE SENSOR RESISTANCE (ohms)
1 2WD 1124-1243
2 4WD PART TIME 650-719
3 4WD FULL TIME 389-431
4 NEUTRAL 199-221
5 4WD LOW 57-64
Fig. 96 Position Sensor Linear Movement
1 - POSITION 1 - 10mm  0.5mm
2 - POSITION 2 - 12mm  0.5mm
3 - POSITION 3 - 14mm  0.5mm
4 - POSITION 4 - 16mm  0.5mm
5 - POSITION 5 - 18mm  0.5mm
6 - POSITION 6 - 20mm 0.5mm - FULL EXTENSION
Fig. 95 Transfer Case Position Sensor and
Connector
1 - TRANSFER CASE POSITION SENSOR CONNECTOR
2 - TRANSFER CASE POSITION SENSOR
3 - TRANSFER CASE
4 - OUTPUT SPEED SENSOR CONNECTOR
WJTRANSFER CASE - NV242 21 - 311

OPERATION
Under normal driving conditions, the system oper-
ates conventionally, and the majority of available
torque is applied to the rear wheels. However, when
front-to-rear wheel speed variations exist, the pro-
gressive differential transfers torque to the axle with
the better traction, thus minimizing wheel spin and
maximizing control.
The key to this design is a progressive coupling
(Fig. 3), which is supplied with pressurized oil by a
gerotor style pump. The pump rotor and case are
driven by the front and rear driveshafts respectively,
and deliver pressurized oil flow to the coupling in
proportion to their speed difference. The progressive
coupling contains a multi-disc clutch pack that is
alternately splined to the front and rear driveshafts,
and controls torque variation between the front and
rear driveshafts as dictated by the pump.
A set of orifices and valves control the speed-differ-
ential starting point and rate of torque transfer rise
in the clutch. This allows the system to disregard the
normal speed differences between axles that result
from variations in front-to-rear loading and typical
cornering.
Transfer case operating ranges are selected with a
floor mounted shift lever. The shift lever is connectedto the transfer case range lever by an adjustable
cable. Range positions are marked on the shifter
bezel plate.
DIAGNOSIS AND TESTING - TRANSFER CASE - NV247
CONDITION POSSIBLE CAUSE CORRECTION
TRANSFER CASE DIFFICULT TO
SHIFT OR WILL NOT SHIFT INTO
DESIRED RANGE1. Vehicle speed too great to permit
shifting1. Reduce speed to 3-4 km/h (2-3
mph) before attempting to shift
2. Transfer case external shift cable
binding2. Lubricate, repair or replace cable,
or thighten loose components as
necessary
3. Insufficient or incorrect lubricant 3. Drain and refill to edge of fill hole
with correct lubricant
4. Internal components binding,
worn, or damaged4. Disassemble unit and replace
worn or damaged components as
necessary
TRANSFER CASE NOISY IN ALL
MODES1. Insufficient or incorrect lubricant 1. Drain and refill to edge of fill hole
with correct lubricant.If unit is still
noisy after drain and refill,
disassembly and inspection may
be required to locate source of
noise
Fig. 3 Progressive Coupling
21 - 316 TRANSFER CASE - NV247WJ
TRANSFER CASE - NV247 (Continued)

²Unsatisfactory ride
²Vehicle drift
For proper tire pressure specification refer to the
Tire Inflation Pressure Chart provided with the vehi-
cles Owners Manual. A Certification Label on the
drivers side door pillar provides the minimum tire
and rim size for the vehicle. The label also list the
cold inflation pressure for these tires at full load
operation
Tire pressures have been chosen to provide safe
operation, vehicle stability, and a smooth ride. Tire
pressure should be checked cold once a month. Tire
pressure decreases as the ambient temperature
drops. Check tire pressure frequently when ambient
temperature varies widely.
Tire inflation pressures are cold inflation pressure.
The vehicle must sit for at least 3 hours to obtain the
correct cold inflation pressure reading. Or be drivenless than one mile after sitting for 3 hours. Tire
inflation pressures may increase from 2 to 6 pounds
per square inch (psi) during operation. Do not reduce
this normal pressure build-up.
WARNING: OVER OR UNDER INFLATED TIRES CAN
AFFECT VEHICLE HANDLING AND TREAD WEAR.
THIS MAY CAUSE THE TIRE TO FAIL SUDDENLY,
RESULTING IN LOSS OF VEHICLE CONTROL.
DESCRIPTION - TIRE PRESSURE FOR HIGH
SPEED
Where speed limits allow the vehicle to be driven
at high speeds, correct tire inflation pressure is very
important. For speeds up to and including 120 km/h
(75 mph), tires must be inflated to the pressures
shown on the tire placard. For continuous speeds in
excess of 120 km/h (75 mph), tires must be inflated
to the maximum pressure specified on the tire side-
wall.
Vehicles loaded to the maximum capacity should
not be driven at continuous speeds above 75 mph
(120 km/h).
For emergency vehicles that are driven at speeds
over 90 mph (144 km/h), special high speed tires
must be used. Consult tire manufacturer for correct
inflation pressure recommendations.
DESCRIPTION - REPLACEMENT TIRES
The original equipment tires provide a proper bal-
ance of many characteristics such as:
²Ride
²Noise
²Handling
²Durability
²Tread life
²Traction
²Rolling resistance
²Speed capability
It is recommended that tires equivalent to the orig-
inal equipment tires be used when replacement is
needed.
Failure to use equivalent replacement tires may
adversely affect the safety and handling of the vehi-
cle.
The use of oversize tires may cause interference
with vehicle components. Under extremes of suspen-
sion and steering travel, interference with vehicle
components may cause tire damage.
WARNING: FAILURE TO EQUIP THE VEHICLE WITH
TIRES HAVING ADEQUATE SPEED CAPABILITY
CAN RESULT IN SUDDEN TIRE FAILURE.
Fig. 13 Under Inflation Wear
1 - THIN TIRE THREAD AREAS
Fig. 14 Over Inflation Wear
1 - THIN TIRE THREAD AREA
WJTIRES/WHEELS 22 - 7
TIRES (Continued)

leak area. If the hose cannot be positioned without
being held, have someone help do the water test.
Some water leaks must be tested for a considerable
length of time to become apparent. When a leak
appears, find the highest point of the water track or
drop. The highest point usually will show the point of
entry. After leak point has been found, repair the
leak and water test to verify that the leak has
stopped.
Locating the entry point of water that is leaking
into a cavity between panels can be difficult. The
trapped water may splash or run from the cavity,
often at a distance from the entry point. Most water
leaks of this type become apparent after accelerating,
stopping, turning, or when on an incline.
MIRROR INSPECTION METHOD
When a leak point area is visually obstructed, use
a suitable mirror to gain visual access. A mirror can
also be used to deflect light to a limited-access area
to assist in locating a leak point.
BRIGHT LIGHT LEAK TEST METHOD
Some water leaks in the luggage compartment can
be detected without water testing. Position the vehi-
cle in a brightly lit area. From inside the darkened
luggage compartment inspect around seals and body
seams. If necessary, have a helper direct a drop light
over the suspected leak areas around the luggage
compartment. If light is visible through a normally
sealed location, water could enter through the open-
ing.
PRESSURIZED LEAK TEST METHOD
When a water leak into the passenger compart-
ment cannot be detected by water testing, pressurize
the passenger compartment and soap test exterior of
the vehicle. To pressurize the passenger compart-
ment, close all doors and windows, start engine, and
set heater control to high blower in HEAT position. If
engine can not be started, connect a charger to the
battery to ensure adequate voltage to the blower.
With interior pressurized, apply dish detergent solu-
tion to suspected leak area on the exterior of the
vehicle. Apply detergent solution with spray device or
soft bristle brush. If soap bubbles occur at a body
seam, joint, seal or gasket, the leak entry point could
be at that location.
WIND NOISE
Wind noise is the result of most air leaks. Air leaks
can be caused by poor sealing, improper body compo-
nent alignment, body seam porosity, or missing plugs
in the engine compartment or door hinge pillar areas.
All body sealing points should be airtight in normal
driving conditions. Moving sealing surfaces will notalways seal airtight under all conditions. At times,
side glass or door seals will allow wind noise to be
noticed in the passenger compartment during high
cross winds. Over compensating on door or glass
adjustments to stop wind noise that occurs under
severe conditions can cause premature seal wear and
excessive closing or latching effort. After a repair pro-
cedure has been performed, test vehicle to verify
noise has stopped before returning vehicle to use.
Wind noise can also be caused by improperly fitted
exterior moldings or body ornamentation. Loose
moldings can flutter, creating a buzzing or chattering
noise. An open cavity or protruding edge can create a
whistling or howling noise. Inspect the exterior of the
vehicle to verify that these conditions do not exist.
VISUAL INSPECTION BEFORE TESTS
Verify that floor and body plugs are in place and
body components are aligned and sealed. If compo-
nent alignment or sealing is necessary, refer to the
appropriate section of this group for proper proce-
dures.
ROAD TESTING WIND NOISE
(1) Drive the vehicle to verify the general location
of the wind noise.
(2) Apply 50 mm (2 in.) masking tape in 150 mm
(6 in.) lengths along weatherstrips, weld seams or
moldings. After each length is applied, drive the vehi-
cle. If noise goes away after a piece of tape is applied,
remove tape, locate, and repair defect.
POSSIBLE CAUSE OF WIND NOISE
²Moldings standing away from body surface can
catch wind and whistle.
²Gaps in sealed areas behind overhanging body
flanges can cause wind-rushing sounds.
²Misaligned movable components.
²Missing or improperly installed plugs in pillars.
²Weld burn through holes.
STANDARD PROCEDURE
STANDARD PROCEDURE - BODY LUBRICATION
All mechanisms and linkages should be lubricated
when necessary. This will maintain ease of operation
and provide protection against rust and excessive
wear. The weatherstrip seals should be lubricated to
prolong their life as well as to improve door sealing.
All applicable exterior and interior vehicle operat-
ing mechanisms should be inspected and cleaned.
Pivot/sliding contact areas on the mechanisms should
then be lubricated.
(1) When necessary, lubricate the operating mech-
anisms with the specified lubricants.
23 - 2 BODYWJ
BODY (Continued)

(18) Remove the four nuts that secure the steering
column to the studs on the instrument panel steering
column support bracket.
(19) Remove the steering column from the instru-
ment panel. Be certain that the steering wheel is
locked and secured from rotation to prevent the loss
of clockspring centering.
(20) Disconnect the left and right body wire har-
ness connectors, the Ignition Off Draw (IOD) wire
harness connector and the fused B(+) wire harness
connector from the connector receptacles of the JB
(Fig. 5).(21) Disconnect the instrument panel wire harness
connectors from the following floor panel transmis-
sion tunnel components (Fig. 6):
²the Airbag Control Module (ACM) connector
receptacle
²the park brake switch terminal
²the transmission shifter connector receptacle.
(22) Remove the two nuts that secure the instru-
ment panel wire harness ground eyelets to the studs
on the floor panel transmission tunnel in front of and
behind the ACM.
(23) Disengage the retainers that secure the
instrument panel wire harness to the floor panel
transmission tunnel.
(24) Remove the instrument panel to center floor
tunnel bracket from the instrument panel and the
floor panel transmission tunnel. (Refer to 23 - BODY/
INSTRUMENT PANEL/IP CENTER FLOOR TUN-
NEL BRACKET - REMOVAL).
(25) Remove the one screw that secures the floor
duct to the heater and air conditioner housing near
the driver side of the floor panel transmission tunnel
and remove the duct from the housing.
(26) If the vehicle is equipped with the manual
heating and air conditioning system, disconnect the
vacuum harness connector located near the driver
side of the floor panel transmission tunnel behind
the driver side floor duct.
(27) Remove the one screw that secures the instru-
ment panel steering column support bracket to the
driver side end of the heater and air conditioner
housing (Fig. 7).
(28) Remove the one screw that secures the instru-
ment panel steering column support bracket to the
intermediate bracket on the driver side dash panel
(Fig. 8).
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
WJINSTRUMENT PANEL SYSTEM 23 - 39
INSTRUMENT PANEL SYSTEM (Continued)

Fig. 6 Floor Panel Transmission Tunnel
1 - AIRBAG CONTROL MODULE CONNECTOR
2 - PARK BRAKE SWITCH CONNECTOR
3 - AIRBAG CONTROL MODULE
4 - NUT (2)
5 - STUD
6 - GROUND EYELET7 - RETAINER
8 - STUD
9 - GROUND EYELET
10 - INSTRUMENT PANEL WIRE HARNESS
11 - TRANSMISSION SHIFTER CONNECTOR
Fig. 7 Instrument Panel to Heater-A/C Housing -
Driver Side
1 - HEATER AND AIR CONDITIONER HOUSING
2 - FLOOR DUCT
3 - INSTRUMENT PANEL STEERING COLUMN SUPPORT
BRACKET
4 - SCREW
Fig. 8 Instrument Panel to Intermediate Bracket
Mounting
1 - DASH PANEL
2 - SCREW
3 - INSTRUMENT PANEL STEERING COLUMN SUPPORT
BRACKET
4 - INTERMEDIATE BRACKET
23 - 40 INSTRUMENT PANEL SYSTEMWJ
INSTRUMENT PANEL SYSTEM (Continued)

(23) Reconnect the instrument panel wire harness
connectors to the following floor panel transmission
tunnel components:
²the Airbag Control Module (ACM) connector
receptacle
²the park brake switch terminal
²the transmission shifter connector receptacle.
(24) Reconnect the left and right body wire har-
ness connectors, the Ignition Off Draw (IOD) wire
harness connector and the fused B(+) wire harness
connector to the connector receptacles of the Junction
Block (JB) and tighten the connector screws (Fig. 5).
Tighten the screws to 4 N´m (36 in. lbs.).
(25) Engage the lower steering column shaft with
the steering shaft coupler and position the steering
column to the mounting studs on the instrument
panel steering column support bracket (Fig. 4).
(26) Install and tighten the four nuts that secure
the steering column to the studs on the instrument
panel steering column support bracket. Tighten the
nuts to 11.8 N´m (105 in. lbs.).
(27) Install and tighten the bolt that secures the
coupler to the lower steering column shaft. Tighten
the bolt to 49 N´m (36 ft. lbs.).
(28) Turn the ignition switch to the On position,
then install the shifter interlock cable connector into
the ignition lock housing receptacle.
(29) Reconnect the instrument panel wire harness
connectors to the following steering column compo-
nents (Fig. 3):
²the two lower clockspring connector receptacles
²the left multi-function switch connector recepta-
cle
²the right multi-function switch connector recep-
tacle
²the two ignition switch connector receptacles
²the shifter interlock solenoid connector recepta-
cle
²if the vehicle is so equipped, the Sentry Key
Immobilizer Module (SKIM) connector receptacle.
(30) Position the lower tilting steering column
shroud to the steering column multi-function switchmounting housing, then install and tighten the screw
that secures the shroud to the housing (Fig. 2).
Tighten the screw to 1.9 N´m (17 in. lbs.).
(31) Position the upper tilting steering column
shroud over the steering column. Align the upper and
lower shrouds with each other and snap the two
halves together.
(32) Reinstall the steering column bracket onto the
instrument panel steering column support bracket.
(Refer to 23 - BODY/INSTRUMENT PANEL/IP
STEERING COLUMN BRACKET - INSTALLA-
TION).
(33) Reinstall the steering column opening cover
onto the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - INSTALLATION).
(34) Reinstall the cluster bezel onto the instru-
ment panel. (Refer to 23 - BODY/INSTRUMENT
PANEL/CLUSTER BEZEL - INSTALLATION).
(35) Reinstall the fuse cover onto the Junction
Block (JB). (Refer to 8 - ELECTRICAL/POWER DIS-
TRIBUTION/FUSE COVER - INSTALLATION).
(36) Reinstall the console onto the floor panel
transmission tunnel. (Refer to 23 - BODY/INTERI-
OR/FLOOR CONSOLE - INSTALLATION).
(37) Reinstall the trim panels onto the right and
left inner cowl sides. (Refer to 23 - BODY/INTERI-
OR/COWL TRIM - INSTALLATION).
(38) Reinstall the scuff plates onto the right and
left front door sills. (Refer to 23 - BODY/INTERIOR/
DOOR SILL SCUFF PLATE - INSTALLATION).
(39) Reinstall the top cover onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL TOP COVER - INSTALLA-
TION).
(40) Reinstall the trim onto the right and left
A-pillars. (Refer to 23 - BODY/INTERIOR/A-PILLAR
TRIM - INSTALLATION).
(41) Reconnect the battery negative cable.
23 - 44 INSTRUMENT PANEL SYSTEMWJ
INSTRUMENT PANEL SYSTEM (Continued)

(15) Remove the two large screws on the glove box
opening upper reinforcement that secure the top pad
to the instrument panel structural duct (Fig. 24).(16) Remove the two small screws on the glove box
opening upper reinforcement that secure the panel
outlets to the instrument panel structural duct.
(17) Remove the center upper bezel from the
instrument panel. (Refer to 23 - BODY/INSTRU-
MENT PANEL/IP CENTER BEZEL - UPPER -
REMOVAL).
(18) Remove the center lower bezel from the
instrument panel. (Refer to 23 - BODY/INSTRU-
MENT PANEL/IP CENTER BEZEL - LOWER -
REMOVAL).
(19) Remove the four screws that secure the radio
to the instrument panel structural duct. Pull the
radio out of the instrument panel only far enough to
access the screws that secure the top pad to the
instrument panel structural duct.
(20) Remove the four screws that secure the heat-
er-A/C control to the instrument panel structural
duct. Pull the heater-A/C control out of the instru-
ment panel only far enough to access the screws that
secure the top pad to the instrument panel structural
duct.
(21) Remove all of the screws that secure the
perimeter of the top pad to the instrument panel
structural duct.
Fig. 23 Instrument Panel Top Pad to Dash Panel Mounting
1 - STUD (4)
2 - NUT (4)3 - INSTRUMENT PANEL
4 - DASH PANEL
Fig. 24 Instrument Panel Top Pad to Glove Box
Opening Mounting
1 - PASSENGER SIDE TRIM BEZEL
2 - PANEL OUTLETS
3 - SMALL SCREWS
4 - LARGE SCREWS
5 - GLOVE BOX OPENING UPPER REINFORCEMENT
WJINSTRUMENT PANEL SYSTEM 23 - 53
INSTRUMENT PANEL TOP PAD (Continued)