2002 JEEP GRAND CHEROKEE Evic

A solenoid can also be described by the method by
which it is controlled. Some of the possibilities
include variable force, pulse-width modulated, con-
stant ON, or duty cycle. The variable force and pulse-
width modulated versions utilize similar methods to
control the current flow through the solenoid to posi-
tion the solenoid plunger at a desired position some-
where between full ON and full OFF. The constant
ON and duty cycled versions control the voltage
across the solenoid to allow either full flow or no flow
through the solenoid's valve.
OPERATION
When an electrical current is applied to the sole-
noid coil, a magnetic field is created which produces
an attraction to the plunger, causing the plunger to
move and work against the spring pressure and the
load applied by the fluid the valve is controlling. The
plunger is normally directly attached to the valve
which it is to operate. When the current is removed
from the coil, the attraction is removed and the
plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and
accomplishes this movement by providing a path for
the magnetic field to flow. By keeping the air gap
between the plunger and the coil to the minimum
necessary to allow free movement of the plunger, the
magnetic field is maximized.
TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 109) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, an
overrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The con-
verter clutch engages in third gear. The torque con-
verter hub drives the transmission oil (fluid) pump
and contains an o-ring seal to better control oil flow.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
CAUTION: The torque converter must be replaced if
a transmission failure resulted in large amounts of
metal or fiber contamination in the fluid. If the fluid
is contaminated, flush the fluid cooler and lines.
Fig. 109 Torque Converter Assembly
1 - TURBINE ASSEMBLY
2-STATOR
3 - CONVERTER HUB
4 - O-RING
5 - IMPELLER ASSEMBLY
6 - CONVERTER CLUTCH PISTON
7 - TURBINE HUB
21 - 264 AUTOMATIC TRANSMISSION - 545RFEWJ
SOLENOIDS (Continued)

position, the clutch will engage after the shift to
third gear, at approximately 56 km/h (35 mph) at
light throttle.
The TCM controls the torque converter by way of
internal logic software. The programming of the soft-
ware provides the TCM with control over the L/R-CC
Solenoid. There are four output logic states that can
be applied as follows:
²No EMCC
²Partial EMCC
²Full EMCC
²Gradual-to-no EMCC
NO EMCC
Under No EMCC conditions, the L/R Solenoid is
OFF. There are several conditions that can result in
NO EMCC operations. No EMCC can be initiated
due to a fault in the transmission or because the
TCM does not see the need for EMCC under current
driving conditions.
PARTIAL EMCC
Partial EMCC operation modulates the L/R Sole-
noid (duty cycle) to obtain partial torque converter
clutch application. Partial EMCC operation is main-
tained until Full EMCC is called for and actuated.
During Partial EMCC some slip does occur. Partial
EMCC will usually occur at low speeds, low load and
light throttle situations.
FULL EMCC
During Full EMCC operation, the TCM increases
the L/R Solenoid duty cycle to full ON after PartialEMCC control brings the engine speed within the
desired slip range of transmission input speed rela-
tive to engine rpm.
GRADUAL-TO-NO EMCC
This operation is to soften the change from Full or
Partial EMCC to No EMCC. This is done at mid-
throttle by decreasing the L/R Solenoid duty cycle.
REMOVAL
(1) Remove transmission and torque converter
from vehicle.
(2) Place a suitable drain pan under the converter
housing end of the transmission.
CAUTION: Verify that transmission is secure on the
lifting device or work surface, the center of gravity
of the transmission will shift when the torque con-
verter is removed creating an unstable condition.
The torque converter is a heavy unit. Use caution
when separating the torque converter from the
transmission.
(3) Pull the torque converter forward until the cen-
ter hub clears the oil pump seal.
(4) Separate the torque converter from the trans-
mission.
INSTALLATION
Check converter hub and drive flats for sharp
edges, burrs, scratches, or nicks. Polish the hub and
flats with 320/400 grit paper or crocus cloth if neces-
sary. Verify that the converter hub o-ring is properly
installed and is free from debris. The hub must be
smooth to avoid damaging the pump seal at installa-
tion.
(1) Lubricate oil pump seal lip with transmission
fluid.
(2) Place torque converter in position on transmis-
sion.
CAUTION: Do not damage oil pump seal or con-
verter hub o-ring while inserting torque converter
into the front of the transmission.
(3) Align torque converter to oil pump seal open-
ing.
(4) Insert torque converter hub into oil pump.
(5) While pushing torque converter inward, rotate
converter until converter is fully seated in the oil
pump gears.
(6) Check converter seating with a scale and
straightedge (Fig. 117). Surface of converter lugs
should be at least 13 mm (1/2 in.) to rear of straight-
edge when converter is fully seated.
(7) If necessary, temporarily secure converter with
C-clamp attached to the converter housing.
Fig. 116 Stator Operation
1 - DIRECTION STATOR WILL FREE WHEEL DUE TO OIL
PUSHING ON BACKSIDE OF VANES
2 - FRONT OF ENGINE
3 - INCREASED ANGLE AS OIL STRIKES VANES
4 - DIRECTION STATOR IS LOCKED UP DUE TO OIL PUSHING
AGAINST STATOR VANES
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 269
TORQUE CONVERTER (Continued)

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

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

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)

DECKLID/HATCH/LIFTGATE/TAILGATE
TABLE OF CONTENTS
page page
EXTERIOR HANDLE
REMOVAL.............................5
INSTALLATION..........................5
FLIP-UP GLASS
REMOVAL.............................5
INSTALLATION..........................6
FLIP-UP GLASS LATCH
REMOVAL.............................6
INSTALLATION..........................6
FLIP-UP GLASS LATCH STRIKER
REMOVAL.............................7
INSTALLATION..........................7
FLIP-UP GLASS SWITCH
REMOVAL.............................7
INSTALLATION..........................7
HINGE
REMOVAL.............................7
INSTALLATION..........................7
LATCH
REMOVAL.............................8
INSTALLATION..........................8LATCH STRIKER
REMOVAL.............................8
INSTALLATION..........................8
LIFTGATE
REMOVAL.............................9
INSTALLATION..........................9
ADJUSTMENTS
LIFTGATE ADJUSTMENT................9
TRIM PANEL
REMOVAL
REMOVAL - LIFTGATE TRIM PANEL........9
REMOVAL - LOWER LIFTGATE OPENING
TRIM PANEL.........................10
INSTALLATION
INSTALLATION - LIFTGATE TRIM PANEL . . . 10
INSTALLATION - LOWER LIFTGATE
OPENING TRIM PANEL.................10
LIFTGATE INSULATOR
REMOVAL.............................10
INSTALLATION.........................10
EXTERIOR HANDLE
REMOVAL
(1) Remove the liftgate trim panel refer to (Refer
to 23 - BODY/DECKLID/HATCH/LIFTGATE/TAIL-
GATE/TRIM PANEL - REMOVAL).
(2) Remove the latch, outside handle linkage, and
power lock connector.
(3) Remove the fasteners attaching the outside
handle to the liftgate.
(4) Remove the outside handle from the liftgate.
INSTALLATION
(1) Position the outside handle on the liftgate.
(2) Install the fasteners attaching outside handle
to liftgate.
(3) Connect outside handle link and power lock
connector.
(4) Install liftgate trim panel, refer to (Refer to 23
- BODY/DECKLID/HATCH/LIFTGATE/TAILGATE/
TRIM PANEL - INSTALLATION).
FLIP-UP GLASS
REMOVAL
CAUTION: DO NOT DISCONNECT THE PROP ROD
CYLINDERS WITH THE LIFTGATE FLIP UP GLASS
CLOSED. THE PROP ROD PISTONS ARE OPER-
ATED BY HIGH PRESSURE GAS. THIS PRESSURE
COULD CAUSE DAMAGE AND/OR PERSONAL
INJURY IF THEY ARE REMOVED WHILE THE PIS-
TONS ARE COMPRESSED.
(1) Using a trim stick or other suitable device, sep-
arate the flip up glass hinge cover from the hinge on
the liftgate (Fig. 1).
(2) Open liftgate flip up glass. Support the glass
for ease of repair.
(3) Using a small flat blade or equivalent tool, gen-
tly pry open the locking caps on the end of the prop
rods.
(4) Remove prop rod cylinders from ball studs.
(5) Lower the flip up glass.
(6) Remove hinge fasteners from liftgate.
(7) Separate flip up glass from liftgate.
WJDECKLID/HATCH/LIFTGATE/TAILGATE 23 - 5

(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)

LIFTGATE
REMOVAL
CAUTION: DO NOT DISCONNECT THE SUPPORT ROD
CYLINDERS WITH THE LIFTGATE CLOSED. THE SUP-
PORT ROD PISTONS ARE OPERATED BY HIGH PRES-
SURE GAS. THIS PRESSURE COULD CAUSE DAMAGE
AND /OR PERSONAL INJURY IF THEY ARE REMOVED
WHILE THE PISTONS ARE COMPRESSED.
(1) Open the liftgate. Support the liftgate for ease
of repair.
(2) Remove the liftgate trim panel.
(3) Remove the prop rods from the liftgate.
(4) Unplug the wire harnesses and disconnect the
washer hose.
(5) Mark the hinge location with a wax pencil or
other suitable device (Fig. 5).
(6) Remove the hinge screws and remove liftgate
from vehicle.
INSTALLATION
(1) Position the liftgate on the vehicle and align
the witness marks.
(2) Install the hinge screws at liftgate. Tighten
hinge screws to 28N´m (21ft. lbs.).
(3) Connect the wire harnesses and the washer
hose.
(4) Install the trim panel.
(5) Install the prop rods.
(6) Close the liftgate and check for proper latching
and alignment.
ADJUSTMENTS
LIFTGATE ADJUSTMENT
The position of the liftgate can be adjusted upward
or downward by the use of slots in the hinge. An
inward or outward adjustment is achieved by use of
slots in the body. If an inward or outward adjustment
is needed, use 3MŸ Fast and Firm or equivalent on
the hinge to body mating surface as a sealant.
TRIM PANEL
REMOVAL
REMOVAL - LIFTGATE TRIM PANEL
NOTE: The liftgate trim panel is attached with
screws and spring clips.
(1) Raise the liftgate.
(2) Remove the screws securing the liftgate trim
panel to the liftgate (Fig. 6).
(3) Disconnect the rear window defroster wires.
(4) Using a trim stick, or other suitable tool, pry
the liftgate trim panel off the liftgate.
Fig. 5 Liftgate
1 - HINGE
2 - LIFTGATE
Fig. 6 Liftgate Trim Panel
1 - LIFTGATE
2 - LIFTGATE TRIM PANEL
WJDECKLID/HATCH/LIFTGATE/TAILGATE 23 - 9