2002 JEEP GRAND CHEROKEE 4.7l

SPECIFICATIONS
TORQUE - STARTER
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Stater Motor (B+) Terminal
(Diesel)27 20
Stater Motor (B+) Terminal
(Except Diesel)11.3 100
Starter Motor Retaining Bolts
(Diesel)27 20
Starter Motor Retaining Bolt
(Forward Facing 4.0L)41 30
Starter Motor Retaining Bolt
(Forward Facing 4.7L)54 40
Starter Motor Retaining Bolt
(Rearward Facing 4.7L)54 40
STARTER MOTOR - GAS POWERED
Starter Motor and Solenoid
Manufacturer Mitsubishi
Engine Application 4.0L/4.7L
Power Rating 1.4 Kilowatt (1.9 Horsepower)
Voltage12 Volts
Number of Fields 4
Number of Poles 4
Number of Brushes 4
Drive Type Planetary Gear Reduction
Free Running Test Voltage 11.2 Volts
Free Running Test Maximum Amperage Draw 90 Amperes
Free Running Test Minimum Speed 2400 rpm
Solenoid Closing Maximum Voltage Required 7.8 Volts
*Cranking Amperage Draw Test 160 Amperes
*Test at operating temperature. Cold engine, tight (new) engine, or heavy oil will increase starter amperage draw.
STARTER MOTOR
DESCRIPTION
The starter motors used for both the 4.0L and the
4.7L engines available in this model are very similar,
but are not interchangeable. Both starter motors are
mounted with two screws to the automatic transmis-
sion torque converter housing and are located on the
right side of the engine.
Each of these starter motors incorporates several
of the same features to create a reliable, efficient,compact, lightweight and powerful unit. The electric
motors of both starters feature four electromagnetic
field coils wound around four pole shoes, and four
brushes contact the motor commutator. Both starter
motors are rated at 1.4 kilowatts (about 1.9 horse-
power) output at 12 volts.
Both of these starter motors are serviced only as a
unit with their starter solenoids, and cannot be
repaired. If either component is faulty or damaged,
the entire starter motor and starter solenoid unit
must be replaced.
WJSTARTING 8F - 35
STARTING (Continued)

REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Raise and support the vehicle.
(3) Remove the lower (forward facing) mounting
screw securing the starter motor to the automatic
transmission torque converter housing (Fig. 9) or
(Fig. 10) .
(4) While supporting the starter motor with one
hand, use the other hand to remove the upper (rear
facing) mounting screw securing the starter motor to
the automatic transmission torque converter housing.
(5) Lower the starter motor from the front of the
automatic transmission torque converter housing far
enough to access and remove the nut that secures
the battery cable eyelet to the solenoid battery termi-
nal (Fig. 11) or (Fig. 12) . Always support the starter
motor during this process, do not let the starter
motor hang from the wire harness.
(6) Remove the battery cable eyelet from the sole-
noid battery terminal. Always support the starter
motor during this process, do not let the starter
motor hang from the wire harness.
(7) Disconnect the solenoid terminal wire harness
connector from the connector receptacle on the
starter solenoid. Always support the starter motor
during this process, do not let the starter motor hang
from the wire harness.
Fig. 9 Starter Motor Remove/Install - 4.0L Engine
1 - SCREW
2 - STARTER MOTOR
3 - SCREW
Fig. 10 Starter Motor Remove/Install - 4.7L Engine
1 - SCREW
2 - STARTER MOTOR
3 - SCREW
Fig. 11 Starter Wire Harness Remove/Install - 4.0L
Engine
1 - BATTERY, STARTER AND GENERATOR WIRE HARNESS
2 - GROUND EYELET
3 - SCREW
4 - NUT
5 - SOLENOID TERMINAL CONNECTOR
6 - SOLENOID BATTERY TERMINAL EYELET
7 - RETAINERS
WJSTARTING 8F - 37
STARTER MOTOR (Continued)

(8) Remove the starter motor from the engine com-
partment.
INSTALLATION
(1) Position the starter motor in the engine com-
partment.
(2) Reconnect the solenoid terminal wire harness
connector to the connector receptacle on the starter
solenoid. Always support the starter motor during
this process, do not let the starter motor hang from
the wire harness.
(3) Install the battery cable eyelet onto the sole-
noid battery terminal. Always support the starter
motor during this process, do not let the starter
motor hang from the wire harness.
(4) Install and tighten the nut that secures the
battery cable eyelet to the solenoid battery terminal.
Tighten the nut to 11.3 N´m (100 in. lbs.). Always
support the starter motor during this process, do not
let the starter motor hang from the wire harness.
(5) Position the starter motor to the front of the
automatic transmission torque converter housing and
loosely install both the upper and lower mounting
screws.
(6) Tighten the lower (forward facing) starter
motor mounting screw. On 4.0L engines, tighten the
screw to 41 N´m (30 ft. lbs.). On 4.7L engines, tighten
the screw to 54 N´m (40 ft. lbs.).(7) Tighten the upper (rearward facing) starter
mounting screw. Tighten the screw to 54 N´m (40 ft.
lbs.).
(8) Lower the vehicle.
(9) Reconnect the battery negative cable.
STARTER MOTOR RELAY
DESCRIPTION
The starter relay is an electromechanical device
that switches battery current to the pull-in coil of the
starter solenoid when the ignition switch is turned to
the Start position. The starter relay is located in the
Power Distribution Center (PDC), in the engine com-
partment. See the fuse and relay layout label affixed
to the inside surface of the PDC cover for starter
relay identification and location.
The starter relay is a International Standards
Organization (ISO) micro-relay. Relays conforming to
the ISO specifications have common physical dimen-
sions, current capacities, terminal patterns, and ter-
minal functions. The ISO micro-relay terminal
functions are the same as a conventional ISO relay.
However, the ISO micro-relay terminal pattern (or
footprint) is different, the current capacity is lower,
and the physical dimensions are smaller than those
of the conventional ISO relay.
The starter relay cannot be repaired or adjusted
and, if faulty or damaged, it must be replaced.
OPERATION
The ISO relay consists of an electromagnetic coil, a
resistor or diode, and three (two fixed and one mov-
able) electrical contacts. The movable (common feed)
relay contact is held against one of the fixed contacts
(normally closed) by spring pressure. When the elec-
tromagnetic coil is energized, it draws the movable
contact away from the normally closed fixed contact,
and holds it against the other (normally open) fixed
contact.
When the electromagnetic coil is de-energized,
spring pressure returns the movable contact to the
normally closed position. The resistor or diode is con-
nected in parallel with the electromagnetic coil in the
relay, and helps to dissipate voltage spikes that are
produced when the coil is de-energized.
DIAGNOSIS AND TESTING - STARTER RELAY
The starter relay (Fig. 13) is located in the Power
Distribution Center (PDC), in the engine compart-
ment. Refer to the fuse and relay layout label affixed
to the underside of the PDC cover for starter relay
identification and location. For complete circuit dia-
grams, refer toStarting Systemin the Contents of
Group 8W - Wiring Diagrams.
Fig. 12 Starter Wire Harness Remove/Install - 4.7L
Engine
1 - SOLENOID BATTERY TERMINAL EYELET
2 - NUT
3 - SOLENOID TERMINAL CONNECTOR
4 - BATTERY STARTER AND GENERATOR WIRE HARNESS
5 - RETAINERS
8F - 38 STARTINGWJ
STARTER MOTOR (Continued)

IGNITION CONTROL
TABLE OF CONTENTS
page page
IGNITION CONTROL
DESCRIPTION..........................1
OPERATION............................1
SPECIFICATIONS
ENGINE FIRING ORDER - 4.0L 6-CYLINDER
ENGINE..............................2
ENGINE FIRING ORDERÐ4.7L V-8 ENGINE . . 2
IGNITION COIL RESISTANCE - 4.0L ENGINE . 2
IGNITION COIL RESISTANCEÐ4.7L V-8
ENGINE..............................2
IGNITION TIMING......................2
SPARK PLUGS........................3
TORQUE - IGNITION SYSTEM............3
AUTO SHUT DOWN RELAY
DESCRIPTION - PCM OUTPUT.............3
OPERATION
OPERATION - PCM OUTPUT.............3
OPERATION - ASD SENSE - PCM INPUT....4
REMOVAL.............................4
INSTALLATION..........................4
CAMSHAFT POSITION SENSOR
DESCRIPTION
DESCRIPTION - 4.0L....................4
DESCRIPTION - 4.7L....................5
OPERATION
OPERATION - 4.0L.....................5
OPERATION - 4.7L.....................5
REMOVAL
REMOVAL - 4.0L.......................6
REMOVAL - 4.7L.......................7INSTALLATION
INSTALLATION - 4.0L...................8
INSTALLATION - 4.7L...................9
COIL RAIL
DESCRIPTION..........................9
OPERATION...........................10
REMOVAL.............................10
INSTALLATION.........................11
IGNITION COIL
DESCRIPTION.........................11
OPERATION...........................12
REMOVAL.............................12
INSTALLATION.........................12
IGNITION COIL CAPACITOR
DESCRIPTION.........................13
OPERATION...........................13
REMOVAL.............................13
INSTALLATION.........................13
KNOCK SENSOR
DESCRIPTION.........................13
OPERATION...........................13
REMOVAL.............................14
INSTALLATION.........................15
SPARK PLUG
DESCRIPTION.........................15
DIAGNOSIS AND TESTING - SPARK PLUG
CONDITIONS.........................15
REMOVAL.............................18
CLEANING............................18
INSTALLATION.........................18
IGNITION CONTROL
DESCRIPTION
Two different ignition systems are used. One type
of system is for the 4.0L 6±cylinder engine. The other
is for the 4.7L V-8 engine.
OPERATION
The 4.0L 6±cylinder engine uses a one-piece coil
rail containing three independent coils. Although cyl-
inder firing order is the same as 4.0L engines of pre-
vious years, spark plug firing is not. The 3 coils dual-
fire the spark plugs on cylinders 1±6, 2±5 and/or 3±4.
When one cylinder is being fired (on compressionstroke), the spark to the opposite cylinder is being
wasted (on exhaust stroke). The one-piece coil bolts
directly to the cylinder head. Rubber boots seal the
secondary terminal ends of the coils to the top of all
6 spark plugs. One electrical connector (located at
the rear end of the coil rail) is used for all three coils.
The 4.7L V-8 engine uses 8 dedicated and individ-
ually fired coil for each spark plug. Each coil is
mounted directly to the top of each spark plug. A sep-
arate electrical connector is used for each coil.
Because of coil design, spark plug cables (second-
ary cables) are not used on either engine. Adistrib-
utor is not usedwith either the 4.0L or 4.7L
engines.
WJIGNITION CONTROL 8I - 1

The ignition system is controlled by the powertrain
control module (PCM) on all engines.
The ignition system consists of:
²Spark Plugs
²Ignition Coil(s)
²Powertrain Control Module (PCM)
²Crankshaft Position Sensor
²Camshaft Position Sensor
²The MAP, TPS, IAC and ECT also have an effect
on the control of the ignition system.
SPECIFICATIONS
ENGINE FIRING ORDER - 4.0L 6-CYLINDER
ENGINEENGINE FIRING ORDERÐ4.7L V-8 ENGINE
IGNITION COIL RESISTANCE - 4.0L ENGINE
PRIMARY RESISTANCE 21-27ÉC (70-80ÉF)
0.71 - 0.88 Ohms
IGNITION COIL RESISTANCEÐ4.7L V-8
ENGINE
PRIMARY RESISTANCE
21-27ÉC (70-80ÉF)SECONDARY
RESISTANCE 21-27ÉC
(70-80ÉF)
0.6 - 0.9 Ohms 6,000 - 9,000 Ohms
IGNITION TIMING
All ignition timing functions are controlled by the
Powertrain Control Module (PCM). Mechanical
adjustments are not needed and can't be made.
On the 4.0L 6±cylinder engine, do not attempt to
rotate the oil pump drive to adjust timing. This
adjustment is used for fuel synchronization after
camshaft position sensor replacement.
8I - 2 IGNITION CONTROLWJ
IGNITION CONTROL (Continued)

SPARK PLUGS
ENGINE PLUG TYPE ELECTRODE GAP
4.0L 6-CYL. RC12ECC 0.89 mm (.035 in.)
4.7L V-8 (Exc. HO) RC12MCC4 1.01 mm (.040 in.)
4.7L V-8 High
Output (HO)RC7PYCB4 1.01 mm (.040 in.)
TORQUE - IGNITION SYSTEM
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Crankshaft Position Sensor
Bolts - 4.0L Engine7- 60
Crankshaft Position Sensor
Bolt - 4.7L V-8 Engine28 21 -
Camshaft Position
Sensor±to±base bolts - 4.0L
Engine2- 15
Camshaft Position Sensor
Bolt - 4.7L V-8 Engine12 - 106
Oil Pump Drive Hold-down
Bolt - 4.0L Engine23 17 -
Ignition Coil Rail Mounting
Bolts - 4.0L Engine29 - 250
Ignition Coil Mounting Nut -
4.7L V-8 Engine8- 70
* Knock Sensor Bolt - 4.7L
HO V-8 Engine*20 *15 -
Spark Plugs - 4.0L Engine 35-41 26-30 -
Spark Plugs - 4.7L V-8
Engine24-30 18-22 -
* Do not apply any sealant,
thread-locker or adhesive to
bolts. Poor sensor
performance may result.
Refer to Removal / Installation
for additional information.
AUTO SHUT DOWN RELAY
DESCRIPTION - PCM OUTPUT
The 5±pin, 12±volt, Automatic Shutdown (ASD)
relay is located in the Power Distribution Center
(PDC). Refer to label on PDC cover for relay location.
OPERATION
OPERATION - PCM OUTPUT
The ASD relay supplies battery voltage (12+ volts)
to the fuel injectors and ignition coil(s). With certain
emissions packages it also supplies 12±volts to the
oxygen sensor heating elements.
The ground circuit for the coil within the ASD
relay is controlled by the Powertrain Control Module
(PCM). The PCM operates the ASD relay by switch-
ing its ground circuit on and off.
WJIGNITION CONTROL 8I - 3
IGNITION CONTROL (Continued)

DESCRIPTION - 4.7L
The Camshaft Position Sensor (CMP) on the 4.7L
V±8 engine is bolted to the front/top of the right cyl-
inder head (Fig. 4).
OPERATION
OPERATION - 4.0L
The CMP sensor contains a hall effect device called
a sync signal generator to generate a fuel sync sig-
nal. This sync signal generator detects a rotating
pulse ring (shutter) on the oil pump drive shaft (Fig.
2). The pulse ring rotates 180 degrees through the
sync signal generator. Its signal is used in conjunc-
tion with the crankshaft position sensor to differenti-
ate between fuel injection and spark events. It is also
used to synchronize the fuel injectors with their
respective cylinders.
When the leading edge of the pulse ring (shutter)
enters the sync signal generator, the following occurs:
The interruption of magnetic field causes the voltage
to switch high resulting in a sync signal of approxi-
mately 5 volts.When the trailing edge of the pulse ring (shutter)
leaves the sync signal generator, the following occurs:
The change of the magnetic field causes the sync sig-
nal voltage to switch low to 0 volts.
OPERATION - 4.7L
The CMP sensor contains a hall effect device called
a sync signal generator to generate a fuel sync sig-
nal. This sync signal generator detects notches
located on a tonewheel. The tonewheel is located at
the front of the camshaft for the right cylinder head
(Fig. 5). As the tonewheel rotates, the notches pass
through the sync signal generator. The pattern of the
notches (viewed counter-clockwise from front of
engine) is: 1 notch, 2 notches, 3 notches, 3 notches, 2
notches 1 notch, 3 notches and 1 notch. The signal
from the CMP sensor is used in conjunction with the
crankshaft position sensor to differentiate between
fuel injection and spark events. It is also used to syn-
chronize the fuel injectors with their respective cylin-
ders.
Fig. 3 CMP LocationÐ4.0L Engine
1 - OIL FILTER
2 - CAMSHAFT POSITION SENSOR
3 - CLAMP BOLT
4 - HOLD-DOWN CLAMP
5 - MOUNTING BOLTS (2)
6 - ELEC. CONNECTORFig. 4 CMP LocationÐ4.7L Engine
1 - RIGHT CYLINDER HEAD
2 - CAMSHAFT POSITION SENSOR
3 - MOUNTING BOLT
4 - ELEC. CONNECTOR
WJIGNITION CONTROL 8I - 5
CAMSHAFT POSITION SENSOR (Continued)

REMOVAL
REMOVAL - 4.0L
The Camshaft Position Sensor (CMP) on the 4.0L
6±cylinder engine is bolted to the top of the oil pump
drive shaft assembly (Fig. 6). The sensor and drive
shaft assembly is located on the right side of the
engine near the oil filter (Fig. 7).
The rotational position of oil pump drive deter-
mines fuel synchronization only. It does not deter-
mine ignition timing.
NOTE: Do not attempt to rotate the oil pump drive
to modify ignition timing.
Two different proceduresare used for removal
and installation. The first procedure will detail
removal and installation of the sensor only. The sec-
ond procedure will detail removal and installation of
the sensor and oil pump drive shaft assembly. The
second procedure is to be used if the engine has been
disassembled.
An internal oil seal is used in the drive shaft hous-
ing that prevents engine oil at the bottom of the sen-
sor. The seal is not serviceable.
SENSOR ONLY - 4.0L
(1) Disconnect electrical connector at CMP sensor
(Fig. 7).
(2) Remove 2 sensor mounting bolts (Fig. 6) or
(Fig. 7).
(3) Remove sensor from oil pump drive.
OIL PUMP DRIVE AND SENSOR - 4.0L
If the CMP and oil pump drive are to be
removed and installed, do not allow engine
crankshaft or camshaft to rotate. CMP sensor
relationship will be lost.
(1) Disconnect electrical connector at CMP sensor
(Fig. 7).
(2) Remove 2 sensor mounting bolts (Fig. 6) or
(Fig. 7).
(3) Remove sensor from oil pump drive.
(4) Before proceeding to next step, mark and note
rotational position of oil pump drive in relationship
to engine block. After installation, the CMP sensor
should face rear of engine 0É.
(5) Remove hold-down bolt and clamp (Fig. 7).
Fig. 5 CMP Sensor and TonewheelÐ4.7L Engine
1 - NOTCHES
2 - RIGHT CYLINDER HEAD
3 - CAMSHAFT POSITION SENSOR
4 - TONEWHEEL
Fig. 6 CMP and Oil Pump Drive Shaft - 4.0L Engine
1 - CAMSHAFT POSITION SENSOR
2 - MOUNTING BOLTS (2)
3 - PULSE RING
4 - DRIVE GEAR (TO CAMSHAFT)
5 - OIL PUMP DRIVESHAFT
6 - SENSOR BASE (OIL PUMP DRIVESHAFT ASSEMBLY)
8I - 6 IGNITION CONTROLWJ
CAMSHAFT POSITION SENSOR (Continued)