2002 JEEP GRAND CHEROKEE starter switch

(23) Inspect for pinched or leaking fuel tubes/lines.
Inspect for pinched, cracked or leaking fuel hoses.
(24) Inspect for exhaust system restrictions such
as pinched exhaust pipes, collapsed muffler or
plugged catalytic convertor.
(25) If equipped with automatic transmission, ver-
ify electrical harness is firmly connected to park/neu-
tral switch and to transmission components.
(26) Verify fuel pump module pigtail harness elec-
trical connector (Fig. 15) is firmly connected to body
harness connector.
(27) Inspect fuel line harness (from fuel pump
module) at fuel filter/fuel pressure regulator (Fig. 15)
for chaffing, cracks or leaks.
(28) Verify battery cable and solenoid feed wire
connections to starter solenoid are tight and clean.
(29) Inspect for chaffed wires or wires rubbing up
against other components.
(30) Inspect for chaffed vacuum lines or lines rub-
bing up against other components.
Fig. 15 Fuel Filter/Fuel Pressure Regulator Location
1 - FUEL RETURN LINE
2 - FUEL SUPPLY LINE (TO FUEL RAIL)
3 - FUEL FILTER/FUEL PRESSURE REGULATOR
4 - FUEL PRESSURE LINE
5 - REAR AXLE
6 - ELEC. CONNECTOR
7 - EVAP LINE
14 - 38 FUEL INJECTIONWJ
FUEL INJECTION (Continued)

(5) Push sensor against flywheel/drive plate. With
sensor pushed against flywheel/drive plate, tighten
mounting bolt to 7 N´m (60 in. lbs.) torque.
(6) Route sensor wiring harness into wire shield.
(7) Connect sensor pigtail harness electrical con-
nector to main wiring harness.
INSTALLATION - 4.7L
(1) Clean out machined hole in engine block.
(2) Apply a small amount of engine oil to sensor
o-ring.
(3) Install sensor into engine block with a slight
rocking action. Do not twist sensor into position as
damage to o-ring may result.
CAUTION: Before tightening sensor mounting bolt,
be sure sensor is completely flush to cylinder
block. If sensor is not flush, damage to sensor
mounting tang may result.
(4) Install mounting bolt and tighten to 28 N´m
(21 ft. lbs.) torque.
(5) Connect electrical connector to sensor.
(6) Install starter motor. Refer to Starter Removal/
Installation.
FUEL INJECTOR
DESCRIPTION
A separate fuel injector (Fig. 24) is used for each
individual cylinder.
OPERATION
OPERATION
The fuel injectors are electrical solenoids. The
injector contains a pintle that closes off an orifice at
the nozzle end. When electric current is supplied to
the injector, the armature and needle move a short
distance against a spring, allowing fuel to flow out
the orifice. Because the fuel is under high pressure, a
fine spray is developed in the shape of a pencil
stream. The spraying action atomizes the fuel, add-
ing it to the air entering the combustion chamber.
The top (fuel entry) end of the injector (Fig. 24) is
attached into an opening on the fuel rail.
The nozzle (outlet) ends of the injectors are posi-
tioned into openings in the intake manifold just
above the intake valve ports of the cylinder head.
The engine wiring harness connector for each fuel
injector is equipped with an attached numerical tag
(INJ 1, INJ 2 etc.). This is used to identify each fuel
injector.
The injectors are electrically energized, individu-
ally and in a sequential order by the Powertrain Con-
trol Module (PCM). The PCM will adjust injector
pulse width by switching the ground path to each
individual injector on and off. Injector pulse width is
the period of time that the injector is energized. The
PCM will adjust injector pulse width based on vari-
ous inputs it receives.
Battery voltage is supplied to the injectors through
the ASD relay.
The PCM determines injector pulse width based on
various inputs.
OPERATION - PCM OUTPUT
The nozzle ends of the injectors are positioned into
openings in the intake manifold just above the intake
valve ports of the cylinder head. The engine wiring
harness connector for each fuel injector is equipped
with an attached numerical tag (INJ 1, INJ 2 etc.).
This is used to identify each fuel injector with its
respective cylinder number.
The injectors are energized individually in a
sequential order by the Powertrain Control Module
(PCM). The PCM will adjust injector pulse width by
switching the ground path to each individual injector
on and off. Injector pulse width is the period of time
that the injector is energized. The PCM will adjust
injector pulse width based on various inputs it
receives.
Battery voltage (12 volts +) is supplied to the injec-
tors through the ASD relay. The ASD relay will shut-
down the 12 volt power source to the fuel injectors if
the PCM senses the ignition is on, but the engine is
not running. This occurs after the engine has not
been running for approximately 1.8 seconds.
Fig. 24 Fuel InjectorÐ4.0L/4.7L Engines
1 - FUEL INJECTOR
2 - NOZZLE
3 - TOP (FUEL ENTRY)
WJFUEL INJECTION 14 - 43
CRANKSHAFT POSITION SENSOR (Continued)

REMOVAL
The overdrive unit can be removed and serviced
separately. It is not necessary to remove the entire
transmission assembly to perform overdrive unit
repairs.
If only the overdrive unit requires service, refer to
Overdrive Removal for proper procedures.
CAUTION: The transmission and torque converter
must be removed as an assembly to avoid compo-
nent damage. The converter driveplate, pump bush-
ing, or oil seal can be damaged if the converter is
left attached to the driveplate during removal. Be
sure to remove the transmission and converter as
an assembly.
(1) Disconnect battery negative cable.
(2) Disconnect and lower or remove necessary
exhaust components.
(3) Disconnect fluid cooler lines at transmission.
(4) Remove starter motor. (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - REMOVAL)
(5) Disconnect and remove crankshaft position sen-
sor. (Refer to 14 - FUEL SYSTEM/FUEL INJEC-
TION/CRANKSHAFT POSITION SENSOR -
REMOVAL) Retain sensor attaching bolts.
CAUTION: The crankshaft position sensor will be
damaged if the transmission is removed, or
installed, while the sensor is still bolted to the
engine block, or transmission (4.0L only). To avoid
damage, be sure to remove the sensor before
removing the transmission.
(6) Remove the bolts holding the bell housing
brace to the transmission.
(7) Remove nut holding the bell housing brace to
the engine to transmission bending brace.
(8) Remove the bell housing brace from the trans-
mission (Fig. 13).
(9) Remove the bolt holding the torque converter
cover to the transmission.
(10) Remove the torque converter cover from the
transmission.
(11) If transmission is being removed for overhaul,
remove transmission oil pan, drain fluid and reinstall
pan.
(12) Remove fill tube bracket bolts and pull tube
out of transmission. Retain fill tube seal. On4x4
models, it will also be necessary to remove bolt
attaching transfer case vent tube to converter hous-
ing.
(13) Rotate crankshaft in clockwise direction until
converter bolts are accessible. Then remove bolts one
at a time. Rotate crankshaft with socket wrench on
dampener bolt.(14) Mark propeller shaft and axle yokes for
assembly alignment. Then disconnect and remove
propeller shaft. On4x4models, remove both propel-
ler shafts.
(15) Disconnect wires from park/neutral position
switch and transmission solenoid.
(16) Disconnect gearshift cable from transmission
manual valve lever (Fig. 14).
Fig. 13 Bell Housing Brace and Converter Cover
1 - Transmission
2 - Torque Converter Cover
3 - Bellhousing Brace
Fig. 14 Transmission Shift Cable
1 - SHIFT CABLE
2 - MANUAL LEVER
3 - MANUAL LEVER
WJAUTOMATIC TRANSMISSION - 42RE 21 - 27
AUTOMATIC TRANSMISSION - 42RE (Continued)

(11) Move transmission forward. Then raise, lower
or tilt transmission to align converter housing with
engine block dowels.
(12) Carefully work transmission forward and over
engine block dowels until converter hub is seated in
crankshaft.
(13) Install two bolts to attach converter housing
to engine.
(14) Install the upper transmission bending braces
to the torque converter housing and the overdrive
unit. Tighten the bolts to 41 N´m (30 ft.lbs.).
(15) Install remaining torque converter housing to
engine bolts. Tighten to 68 N´m (50 ft.lbs.).
(16) Install rear transmission crossmember.
Tighten crossmember to frame bolts to 68 N´m (50
ft.lbs.).
(17) Install rear support to transmission. Tighten
bolts to 47 N´m (35 ft.lbs.).
(18) Lower transmission onto crossmember and
install bolts attaching transmission mount to cross-
member. Tighten clevis bracket to crossmember bolts
to 47 N´m (35 ft.lbs.). Tighten the clevis bracket to
rear support bolt to 68 N´m (50 ft.lbs.).
(19) Remove engine support fixture.
(20) Install crankshaft position sensor. (Refer to 14
- FUEL SYSTEM/FUEL INJECTION/CRANKSHAFT
POSITION SENSOR - INSTALLATION)
(21) Install new plastic retainer grommet on any
shift cable that was disconnected. Grommets should
not be reused. Use pry tool to remove rod from grom-
met and cut away old grommet. Use pliers to snap
new grommet into cable and to snap grommet onto
lever.
(22) Connect gearshift and throttle valve cable to
transmission.
(23) Connect wires to park/neutral position switch
and transmission solenoid connector. Be sure trans-
mission harnesses are properly routed.CAUTION: It is essential that correct length bolts be
used to attach the converter to the driveplate. Bolts
that are too long will damage the clutch surface
inside the converter.
(24) Install all torque converter-to-driveplate bolts
by hand.
(25) Verify that the torque converter is pulled
flush to the driveplate. Tighten bolts to 31 N´m (270
in. lbs.).
(26) Install converter housing access cover. Tighten
bolt to 23 N´m (200 in.lbs.).
(27) Install the bell housing brace to the torque
converter cover and the engine to transmission bend-
ing brace. Tighten the bolts and nut to 41 N´m (30
ft.lbs.).
(28) Install starter motor (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - INSTALLA-
TION) and cooler line bracket.
(29) Connect cooler lines to transmission.
(30) Install transmission fill tube. Install new seal
on tube before installation.
(31) Install exhaust components.
(32) Install transfer case. Tighten transfer case
nuts to 35 N´m (26 ft.lbs.).
(33) Install the transfer case shift cable to the
cable support bracket and the transfer case shift
lever.
(34) Align and connect propeller shaft(s).
(35) Adjust gearshift linkage and throttle valve
cable if necessary.
(36) Lower vehicle.
(37) Fill transmission with MopartATF +4, type
9602, fluid.
21 - 42 AUTOMATIC TRANSMISSION - 42REWJ
AUTOMATIC TRANSMISSION - 42RE (Continued)

PARK/NEUTRAL POSITION
SWITCH
DIAGNOSIS AND TESTING - PARK/NEUTRAL
POSITION SWITCH
The center terminal of the park/neutral position
switch is the starter-circuit terminal. It provides the
ground for the starter solenoid circuit through the
selector lever in PARK and NEUTRAL positions only.
The outer terminals on the switch are for the backup
lamp circuit.
SWITCH TEST
To test the switch, remove the wiring connector.
Test for continuity between the center terminal and
the transmission case. Continuity should exist only
when the transmission is in PARK or NEUTRAL.Shift the transmission into REVERSE and test
continuity at the switch outer terminals. Continuity
should exist only when the transmission is in
REVERSE. Continuity should not exist between the
outer terminals and the case.
Check gearshift linkage adjustment before replac-
ing a switch that tests faulty.
REMOVAL
(1) Raise vehicle and position drain pan under
switch.
(2) Disconnect switch wires.
(3) Remove switch from case.
INSTALLATION
(1) Move shift lever to PARK and NEUTRAL posi-
tions. Verify that switch operating lever fingers are
centered in switch opening in case (Fig. 198).
Fig. 197 Brake Transmission Shift Interlock
1 - SHIFT MECHANISM 4 - STEERING COLUMN ASSEMBLY
2 - SHIFTER BTSI LEVER 5 - INTERLOCK CABLE
3 - ADJUSTMENT CLIP
WJAUTOMATIC TRANSMISSION - 42RE 21 - 109
PARK LOCK CABLE (Continued)

TORQUE CONVERTER LEAK POINTS
Possible sources of converter leaks are:
(1) Leaks at the weld joint around the outside
diameter weld (Fig. 7).
(2) Leaks at the converter hub weld (Fig. 7).
STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR
Damaged or worn threads in the aluminum trans-
mission case and valve body can be repaired by the
use of Heli-CoilsŸ, or equivalent. This repair con-
sists of drilling out the worn-out damaged threads.
Then tap the hole with a special Heli-CoilŸ tap, or
equivalent, and installing a Heli-CoilŸ insert, or
equivalent, into the hole. This brings the hole back to
its original thread size.
Heli-CoilŸ, or equivalent, tools and inserts are
readily available from most automotive parts suppli-
ers.
REMOVAL
CAUTION: The transmission and torque converter
must be removed as an assembly to avoid compo-
nent damage. The converter driveplate, converter
hub o-ring, or oil seal can be damaged if the con-
verter is left attached to the driveplate during
removal. Be sure to remove the transmission and
converter as an assembly.
(1) Disconnect the negative battery cable.
(2) Raise and support the vehicle
(3) Mark propeller shaft and axle yokes for assem-
bly alignment.
(4) Remove the rear propeller shaft
(5) Remove the front propeller shaft.
(6) Remove the engine to transmission collar (Fig.
8).
(7) Remove the exhaust support bracket from the
rear of the transmission.
(8) Disconnect and lower or remove any necessary
exhaust components.
(9) Remove the starter motor.
(10) Rotate crankshaft in clockwise direction until
converter bolts are accessible. Then remove bolts one
at a time. Rotate crankshaft with socket wrench on
dampener bolt.
(11) Disconnect wires from solenoid and pressure
switch assembly, input and output speed sensors, and
line pressure sensor.
Fig. 7 Torque Converter Assembly
1 - TURBINE ASSEMBLY
2-STATOR
3 - CONVERTER HUB
4 - O-RING
5 - IMPELLER ASSEMBLY
6 - CONVERTER CLUTCH PISTON
7 - TURBINE HUB
Fig. 8 Transmission Collar
1 - ENGINE
2 - ENGINE TO TRANSMISSION COLLAR
3 - TRANSMISSION
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 183
AUTOMATIC TRANSMISSION - 545RFE (Continued)

(5) Carefully insert converter in oil pump. Then
rotate converter back and forth until fully seated in
pump gears.
(6) Check converter seating with steel scale and
straightedge (Fig. 52). Surface of converter lugs
should be at least 13 mm (1/2 in.) to rear of straight-
edge when converter is fully seated.
(7) Temporarily secure converter with C-clamp.
(8) Position transmission on jack and secure it
with chains.
(9) Check condition of converter driveplate.
Replace the plate if cracked, distorted or damaged.
Also be sure transmission dowel pins are seated
in engine block and protrude far enough to
hold transmission in alignment.
(10) Apply a light coating of MopartHigh Temp
Grease to the torque converter hub pocket in the rear
pocket of the engine's crankshaft.
(11) Raise transmission and align the torque con-
verter with the drive plate and the transmission con-
verter housing with the engine block.
(12) Move transmission forward. Then raise, lower,
or tilt transmission to align the converter housing
with the engine block dowels.
(13) Carefully work transmission forward and over
engine block dowels until converter hub is seated in
crankshaft. Verify that no wires, or the transmission
vent hose, have become trapped between the engine
block and the transmission.
(14) Install two bolts to attach the transmission to
the engine.(15) Install remaining torque converter housing to
engine bolts. Tighten to 68 N´m (50 ft.lbs.).
(16) Install rear transmission crossmember.
Tighten crossmember to frame bolts to 68 N´m (50
ft.lbs.).
(17) Install rear support to transmission. Tighten
bolts to 47 N´m (35 ft.lbs.).
(18) Lower transmission onto crossmember and
install bolts attaching transmission mount to cross-
member. Tighten clevis bracket to crossmember bolts
to 47 N´m (35 ft.lbs.). Tighten the clevis bracket to
rear support bolt to 68 N´m (50 ft.lbs.).
(19) Remove engine support fixture.
(20) Install new plastic retainer grommet on any
shift cable that was disconnected. Grommets should
not be reused. Use pry tool to remove rod from grom-
met and cut away old grommet. Use pliers to snap
new grommet into cable and to snap grommet onto
lever.
(21) Connect gearshift cable to transmission.
(22) Connect wires to solenoid and pressure switch
assembly connector, input and output speed sensors,
and line pressure sensor. Be sure transmission har-
nesses are properly routed.
CAUTION: It is essential that correct length bolts be
used to attach the converter to the driveplate. Bolts
that are too long will damage the clutch surface
inside the converter.
(23) Install all torque converter-to-driveplate bolts
by hand.
(24) Verify that the torque converter is pulled
flush to the driveplate. Tighten bolts to 31 N´m (270
in. lbs.).
(25) Install starter motor and cooler line bracket.
(26) Connect cooler lines to transmission.
(27) Install transmission fill tube.
(28) Install exhaust components.
(29) Install transfer case. Tighten transfer case
nuts to 35 N´m (26 ft.lbs.).
(30) Install the transfer case shift cable to the
cable support bracket and the transfer case shift
lever.
(31) Install the transmission collar onto the trans-
mission and the engine. Tighten the bolts to 54 N´m
(40 ft.lbs.).
(32) Align and connect propeller shaft(s).
(33) Adjust gearshift cable if necessary.
(34) Lower vehicle.
(35) Fill transmission with MopartATF +4, type
9602, Automatic Transmission fluid.
Fig. 52 Checking Torque Converter Seating - Typical
1 - SCALE
2 - STRAIGHTEDGE
21 - 198 AUTOMATIC TRANSMISSION - 545RFEWJ
AUTOMATIC TRANSMISSION - 545RFE (Continued)

(8) Install the transmission in the vehicle.
(9) Fill the transmission with the recommended
fluid.
TRANSMISSION CONTROL
RELAY
DESCRIPTION
The relay is supplied fused B+ voltage, energized
by the TCM, and is used to supply power to the sole-
noid pack when the transmission is in normal oper-
ating mode.
OPERATION
When the relay is ªoffº, no power is supplied to the
solenoid pack and the transmission is in ªlimp-inº
mode. After a controller reset, the TCM energizes the
relay. Prior to this, the TCM verifies that the con-
tacts are open by checking for no voltage at the
switched battery terminals. After this is verified, the
voltage at the solenoid pack pressure switches is
checked. After the relay is energized, the TCM mon-
itors the terminals to verify that the voltage is
greater than 3 volts.
TRANSMISSION RANGE
SENSOR
DESCRIPTION
The Transmission Range Sensor (TRS) is part of
the solenoid module, which is mounted to the top of
the valve body inside the transmission.
The Transmission Range Sensor (TRS) has five
switch contact pins that:
²Determine shift lever position
²Supply ground to the Starter Relay in Park and
Neutral only.
²Supply +12 V to the backup lamps in Reverse
only.
The TRS also has an integrated temperature sen-
sor (thermistor) that communicates transmission
temperature to the TCM and PCM.
OPERATION
The Transmission Range Sensor (TRS) communi-
cates shift lever position to the TCM as a combina-
tion of open and closed switches. Each shift lever
position has an assigned combination of switch states
(open/closed) that the TCM receives from four sense
circuits. The TCM interprets this information and
determines the appropriate transmission gear posi-
tion and shift schedule.
There are many possible combinations of open and
closed switches (codes). Seven of these possible codes
are related to gear position and five are recognized
as ªbetween gearº codes. This results in many codes
which shouldnever occur. These are called
ªinvalidº codes. An invalid code will result in a DTC,
and the TCM will then determine the shift lever
position based on pressure switch data. This allows
reasonably normal transmission operation with a
TRS failure.
GEAR C5 C4 C3 C2 C1
ParkCL OP OP CL CL
Temp 1CL OP OP CL OP
ReverseOP OP OP CL OP
Temp 2OP OP CL CL OP
Neutral 1OP OP CL CL CL
Neutral 2OP CL CL CL CL
Temp 3OP CL CL CL OP
DriveOP CL CL OP OP
Temp 4OP CL OP OP OP
Manual 2CL CL OP OP OP
Temp 5CL OP OP OP OP
Manual 1CL OP CL OP OP
Fig. 117 Checking Torque Converter Seating-Typical
1 - SCALE
2 - STRAIGHTEDGE
21 - 270 AUTOMATIC TRANSMISSION - 545RFEWJ
TORQUE CONVERTER (Continued)