2003 JEEP GRAND CHEROKEE Lock cylinder

DRIVER BLEND DOOR MOTOR/ACTUATOR (LHD) (AZC) - BLACK 2 WAY
CAV CIRCUIT FUNCTION
A C95 20WT/BK (LHD) DRIVER BLEND DOOR DRIVER (B)
B C33 20DB/RD (LHD) DRIVER BLEND DOOR DRIVER (A)
DRIVER BLEND DOOR MOTOR/ACTUATOR (RHD) (AZC)- BLACK 2 WAY
CAV CIRCUIT FUNCTION
A C33 20DB/RD (RHD) DRIVER BLEND DOOR DRIVER (A)
B C95 20WT/BK (RHD) DRIVER BLEND DOOR DRIVER (B)
DRIVER CURTAIN AIRBAG - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 R73 20LB/BR DRIVER CURTAIN SQUIB LINE 2
2 R75 20LB/OR DRIVER CURTAIN SQUIB LINE 1
DRIVER CYLINDER LOCK SWITCH - GRAY 2 WAY
CAV CIRCUIT FUNCTION
1 G73 20LG/OR DRIVER CYLINDER LOCK SWITCH SENSE
2 Z243 12BK (RHD) GROUND
2 Z28 12BK (LHD) GROUND
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 67

DRIVER DOOR LOCK MOTOR/AJAR SWITCH - BLACK 4 WAY
CAV CIRCUIT FUNCTION
1 G75 18TN/RD DRIVER DOOR AJAR SWITCH SENSE
2 Z243 12BK (RHD) GROUND
2 Z28 12BK (LHD) GROUND
3 P34 18PK/BK DRIVER DOOR UNLOCK DRIVER
4 P35 18OR/BK DRIVER DOOR LOCK DRIVER
DRIVER DOOR MODULE C1 - WHITE 15 WAY
CAV CIRCUIT FUNCTION
1 A146 12OR/WT FUSED B(+)
2 Q23 16RD/WT DRIVER REAR WINDOW DRIVER (DOWN)
3 Q13 16DB DRIVER REAR WINDOW DRIVER (UP)
4 Z28 12BK (LHD) GROUND
4 Z234 12BK (RHD) GROUND
5 P35 18OR/BK DRIVER DOOR LOCK DRIVER
6- -
7 P34 18PK/BK DRIVER DOOR UNLOCK DRIVER
8 D30 20VT/YL (JAPAN) DIAGNOSTIC OUT
9 D25 20YL/VT PCI BUS
10 G73 20LG/OR DRIVER CYLINDER LOCK SWITCH SENSE
11 G75 18TN/RD DRIVER DOOR AJAR SWITCH SENSE
12 E21 20OR/RD DRIVER REAR DOOR SWITCH ILLUMINATION
13 Q11 16LB DRIVER WINDOW DRIVER (UP)
14 - -
15 Q21 16WT DRIVER WINDOW DRIVER (DOWN)
DRIVER DOOR MODULE C2 - BLACK 12 WAY
CAV CIRCUIT FUNCTION
1 P95 20OR MIRROR HORIZONTAL DRIVER
2 C118 20BK/WT MIRROR HEATER GROUND
3 P64 20VT MIRROR VERTICAL POSITION SIGNAL
4 P69 20GY MIRROR SENSOR GROUND
5 P65 20DG MIRROR HORIZONTAL POSITION SIGNAL
6 C117 20BK MIRROR HEATER 12 VOLT SUPPLY
7 P91 20WT MIRROR COMMON DRIVER
8 P93 20RD MIRROR VERTICAL DRIVER
9 M21 20PK/DG COURTESY LAMP DRIVER
10 P110 20YL (BUILT-UP-EXPORT) FOLDING MIRROR RETURN
11 P99 20DB (BUILT-UP-EXPORT) FOLDING MIRROR FEED
12 L121 20BK/RD COURTESY LAMP GROUND
8W - 80 - 68 8W-80 CONNECTOR PIN-OUTWJ

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Coil On Plug NO. 8 (4.7L) BK Right Side of Engine Near Fuel
Injector No.814, 15
Coil Rail (4.0L) BK Right Rear of Engine 10, 11
Compact Disc Changer BK Near Radio N/S
Compact Disc Changer BK Right Rear Quarter Panel 37
Controller Antilock Brake BK Left Front Engine Compartment 3, 4
Coolant Level Sensor LT GY Right Rear of Engine 5
Crankcase Heater (Diesel) BK Near T/O for G105 8
Crankshaft Position Sensor
(Diesel)BK Rear of Engine Near Transmission
Bell HousingN/S
Crankshaft Position Sensor
(Gas)BK Rear of Engine Near Transmission
Bell Housing10, 11, 14, 15, 17
Data Link Connector BK Under Lower Driver's Side of
Instrument Panel20, 21, 22
Diagnostic Junction Port BK At Steering Column 23
Driver Airbag Squib 1 BK In Steering Wheel N/S
Driver Airbag Squib 2 BK In Steering Wheel N/S
Driver Blend Door Motor/
Actuator (AZC)BK On HVAC Housing N/S
Driver Cylinder Lock Switch GY In Driver Door 24, 25
Driver Door Lock Motor/Ajar
SwitchBK In Driver Door 24, 25
Driver Door Module - C1 WT In Driver Door 24, 25
Driver Door Module - C2 BK In Driver Door N/S
Driver Door Module - C3 BK In Driver Door N/S
Driver Front Door Courtesy
LampBK In Driver Door N/S
Driver Front Power Window
MotorBK In Driver Door 24, 25
Driver Heated Seat Back
(Premium I/III)GN At Driver Seat N/S
Driver Heated Seat Cushion
(Premium I/III)BK At Driver Seat N/S
Driver Heated Seat Switch WT Center of Instrument Panel 19 20, 21
Driver Lumbar Motor
(Midline/Premium)BK At Driver Seat N/S
Driver Lumbar Switch
(Midline/Premium)WT At Driver Seat N/S
Driver Power Mirror BK At Driver Door N/S
Driver Power Seat Front Riser
MotorRD At Driver Seat N/S
Driver Power Seat Front Riser
Motor Sensor (Premium II/III)BK At Driver Seat N/S
Driver Power Seat Horizontal
MotorBK At Driver Seat N/S
8W - 91 - 4 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONWJ
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

ENGINE
TABLE OF CONTENTS
page page
ENGINE - 4.0L............................ 1ENGINE - 4.7L........................... 61
ENGINE - 4.0L
TABLE OF CONTENTS
page page
ENGINE - 4.0L
DESCRIPTION..........................2
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - INTRODUCTION............3
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - PERFORMANCE............4
DIAGNOSIS AND TESTINGÐ ENGINE
DIAGNOSIS - MECHANICAL..............6
DIAGNOSIS AND TESTINGÐCYLINDER
COMPRESSION PRESSURE..............8
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE.......8
DIAGNOSIS AND TESTINGÐREAR SEAL
AREA LEAKS..........................9
STANDARD PROCEDURE
STANDARD PROCEDURE - FORM-IN-
PLACE GASKETS AND SEALERS..........9
STANDARD PROCEDURE - REPAIR
DAMAGED OR WORN THREADS.........10
STANDARD PROCEDUREÐHYDROSTATIC
LOCK...............................10
STANDARD PROCEDURE - CYLINDER
BORE HONING.......................10
STANDARD PROCEDURE - ENGINE CORE
AND OIL GALLERY PLUGS..............11
REMOVAL.............................11
INSTALLATION.........................13
SPECIFICATIONS
ENGINE - 4.0L........................14
TORQUE - 4.0L ENGINE................17
AIR CLEANER ELEMENT
REMOVAL - 4.0L........................18
INSTALLATION - 4.0L....................19
AIR CLEANER HOUSING
REMOVAL - 4.0L........................19
INSTALLATION - 4.0L....................19CYLINDER HEAD
DESCRIPTION.........................19
REMOVAL.............................19
CLEANING............................21
INSPECTION..........................21
INSTALLATION.........................21
CYLINDER HEAD COVER(S)
DESCRIPTION.........................22
REMOVAL.............................22
CLEANING............................23
INSPECTION..........................23
INSTALLATION.........................23
INTAKE/EXHAUST VALVES & SEATS
DESCRIPTION.........................23
STANDARD PROCEDURE - VALVE SERVICE . . 23
REMOVAL.............................25
INSTALLATION.........................25
ROCKER ARM / ADJUSTER ASSEMBLY
DESCRIPTION.........................26
OPERATION...........................26
REMOVAL.............................26
CLEANING............................26
INSPECTION..........................27
INSTALLATION.........................27
VALVE STEM SEALS
DESCRIPTION.........................27
VALVE SPRINGS
DESCRIPTION.........................28
STANDARD PROCEDURE - VALVE SPRING
TENSION TEST.......................28
REMOVAL.............................28
INSTALLATION.........................29
ENGINE BLOCK
CLEANING............................30
INSPECTION..........................30
CAMSHAFT & BEARINGS
DESCRIPTION.........................30
WJENGINE 9 - 1

REMOVAL
REMOVAL - CAMSHAFT BEARINGS.......31
REMOVAL - CAMSHAFT................31
INSPECTION
INSPECTION - CAMSHAFT BEARINGS.....31
INSPECTION - CAMSHAFT..............31
INSTALLATION
INSTALLATION - CAMSHAFT BEARINGS . . . 32
INSTALLATION - CAMSHAFT............32
CONNECTING ROD BEARINGS
STANDARD PROCEDURE - FITTING
CONNECTING ROD BEARINGS..........33
CRANKSHAFT
DESCRIPTION.........................35
CRANKSHAFT MAIN BEARINGS
STANDARD PROCEDURE - FITTING
CRANKSHAFT MAIN BEARINGS..........36
REMOVAL.............................39
INSPECTION..........................40
INSTALLATION.........................40
CRANKSHAFT OIL SEAL - FRONT
REMOVAL.............................41
INSTALLATION.........................41
CRANKSHAFT OIL SEAL - REAR
REMOVAL.............................42
INSTALLATION.........................42
HYDRAULIC LIFTERS
DESCRIPTION.........................43
REMOVAL.............................43
CLEANING............................43
INSPECTION..........................43
INSTALLATION.........................43
PISTON & CONNECTING ROD
DESCRIPTION.........................44
STANDARD PROCEDURE - PISTON FITTING . 44
REMOVAL.............................45
INSTALLATION.........................46
PISTON RINGS
STANDARD PROCEDURE - PISTON RING
FITTING.............................47
VIBRATION DAMPER
REMOVAL.............................49
INSTALLATION.........................49STRUCTURAL SUPPORT
REMOVAL.............................49
INSTALLATION.........................50
LUBRICATION
DESCRIPTION.........................50
OPERATION...........................50
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE OIL
PRESSURE..........................51
DIAGNOSIS AND TESTING - ENGINE OIL
LEAK...............................51
OIL
STANDARD PROCEDURE - ENGINE OIL
SERVICE............................53
OIL FILTER
REMOVAL.............................53
INSTALLATION.........................54
OIL PAN
DESCRIPTION.........................54
REMOVAL.............................54
INSTALLATION.........................55
ENGINE OIL PRESSURE SENSOR
DESCRIPTION.........................56
OPERATION...........................56
OIL PUMP
REMOVAL.............................56
INSTALLATION.........................57
INTAKE MANIFOLD
DESCRIPTION.........................57
DIAGNOSIS AND TESTING - INTAKE
MANIFOLD LEAKAGE..................57
REMOVAL.............................57
INSTALLATION.........................57
EXHAUST MANIFOLD
DESCRIPTION.........................58
REMOVAL.............................58
INSTALLATION.........................58
TIMING BELT / CHAIN COVER(S)
REMOVAL.............................58
INSTALLATION.........................58
TIMING BELT/CHAIN AND SPROCKETS
REMOVAL.............................60
INSTALLATION.........................60
ENGINE - 4.0L
DESCRIPTION
The 4.0 Liter (242 CID) six-cylinder engine is an
In-line, lightweight, overhead valve engine. This
engine is designed for unleaded fuel.
The engine cylinder head has dual quench-type
combustion chambers that create turbulence and fast
burning of the air/fuel mixture. This results in better
fuel economy.
The cylinders are numbered 1 through 6 from front
to rear. The firing order is 1-5-3-6-2-4 (Fig. 1).The crankshaft rotation is clockwise, when viewed
from the front of the engine. The crankshaft rotates
within seven main bearings. The camshaft rotates
within four bearings.
The engine Build Date Code is located on a
machined surface on the right side of the cylinder
block between the No.2 and No.3 cylinders (Fig. 2).
The digits of the code identify:
²1st DigitÐThe year (8 = 1998).
²2nd & 3rd DigitsÐThe month (01 - 12).
²4th & 5th DigitsÐThe engine type/fuel system/
compression ratio (MX = A 4.0 Liter (242 CID) 8.7:1
compression ratio engine with a multi-point fuel
injection system).
9 - 2 ENGINE - 4.0LWJ

²6th & 7th DigitsÐThe day of engine build (01 -
31).(1)FOR EXAMPLE:Code * 801MX12 * identifies
a 4.0 Liter (242 CID) engine with a multi-point fuel
injection system, 8.7:1 compression ratio and built on
January 12, 1998.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - INTRODUCTION
Engine diagnosis is helpful in determining the
causes of malfunctions not detected and remedied by
routine maintenance.
These malfunctions may be classified as either
mechanical (e.g., a strange noise), or performance
(e.g., engine idles rough and stalls).
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING - Preformance) or (Refer to 9 - ENGINE - DIAG-
NOSIS AND TESTING - Mechanical). Refer to 14 -
FUEL SYSTEM for fuel system diagnosis.
Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can-
not be isolated with the Service Diagnosis charts.
Information concerning additional tests and diagno-
sis is provided within the following:
²Cylinder Compression Pressure Test (Refer to 9 -
ENGINE - DIAGNOSIS AND TESTING)
²Cylinder Combustion Pressure Leakage Test
(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
²Cylinder Head Gasket Failure Diagnosis (Refer
to 9 - ENGINE/CYLINDER HEAD - DIAGNOSIS
AND TESTING)
²Intake Manifold Leakage Diagnosis (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
DIAGNOSIS AND TESTING)
²Lash Adjuster (Tappet) Noise Diagnosis (Refer to
9 - ENGINE/ENGINE BLOCK/HYDRAULIC LIFT-
ERS (CAM IN BLOCK) - DIAGNOSIS AND TEST-
ING)
²Engine Oil Leak Inspection (Refer to 9 -
ENGINE/LUBRICATION - DIAGNOSIS AND TEST-
ING)
Fig. 1 Engine Firing Order
Fig. 2 Build Date Code Location
1 - YEAR
2 - MONTH
3-DAY
WJENGINE - 4.0L 9 - 3
ENGINE - 4.0L (Continued)

DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE
ENGINE PERFORMANCE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
ENGINE WILL NOT CRANK 1. Weak or dead battery 1. Charge/Replace Battery. (Refer to
8 - ELECTRICAL/BATTERY
SYSTEM/BATTERY - STANDARD
PROCEDURE), for correct
procedures. Check charging system.
(Refer to 8 - ELECTRICAL/
CHARGING - DIAGNOSIS AND
TESTING), for correct procedures.
2. Corroded or loose battery
connections2. Clean/tighten suspect battery/
starter connections
3. Faulty starter or related circuit(s) 3. Check starting system. (Refer to 8
- ELECTRICAL/STARTING -
DIAGNOSIS AND TESTING), for
correct diagnostics/procedures
4. Siezed accessory drive
component4. Remove accessory drive belt and
attempt to start engine. If engine
starts, repair/replace siezed
component.
5. Engine internal mechanical failure
or hydro-static lock5. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING), for
correct diagnostics/procedures
ENGINE CRANKS BUT WILL
NOT START1. No spark 1. Check for spark. (Refer to 8 -
ELECTRICAL/IGNITION CONTROL -
SPECIFICATIONS), for correct
procedures.
2. No fuel 2. Perform fuel pressure test (Refer
to 14 - FUEL SYSTEM/FUEL
DELIVERY/FUEL PUMP -
DIAGNOSIS AND TESTING), and if
necessary, inspect fuel injector(s) and
driver circuits. (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/FUEL
INJECTOR - DIAGNOSIS AND
TESTING), for correct procedures.
3. Low or no engine compression 3. Perform cylinder compression
pressure test. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
ENGINE LOSS OF POWER 1. Worn or burned distributor rotor 1. Install new distributor rotor
2. Worn camshaft position sensor
shaft2. Remove and repair camshaft
position sensor.(Refer to 8 -
ELECTRICAL/IGNITION CONTROL/
CAMSHAFT POSITION SENSOR -
REMOVAL).
9 - 4 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)

DIAGNOSIS AND TESTINGÐCYLINDER
COMPRESSION PRESSURE
The results of a cylinder compression pressure test
can be utilized to diagnose several engine malfunc-
tions.
Ensure the battery is completely charged and the
engine starter motor is in good operating condition.
Otherwise, the indicated compression pressures may
not be valid for diagnosis purposes.
(1) Clean the spark plug recesses with compressed
air.
(2) Remove the spark plugs (Refer to 8 - ELEC-
TRICAL/IGNITION CONTROL/SPARK PLUG -
REMOVAL).
(3) Secure the throttle in the wide-open position.
(4) Disconnect the ignition coil.
(5) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(6) Record the compression pressure on the third
revolution. Continue the test for the remaining cylin-
ders.
(Refer to 9 - ENGINE - SPECIFICATIONS) for the
correct engine compression pressures.
DIAGNOSIS AND TESTING - CYLINDER
COMBUSTION PRESSURE LEAKAGE
The combustion pressure leakage test provides an
accurate means for determining engine condition.
Combustion pressure leakage testing will detect:
²Exhaust and intake valve leaks (improper seat-
ing)
²Leaks between adjacent cylinders or into water
jacket²Any causes for combustion/compression pressure
loss
WARNING: DO NOT REMOVE THE RADIATOR CAP
WITH THE SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM HOT COOLANT CAN
OCCUR.
Check the coolant level and fill as required. DO
NOT install the radiator cap.
Start and operate the engine until it attains nor-
mal operating temperature, then turn OFF the
engine.
Remove the spark plugs.
Remove the oil filler cap.
Remove the air cleaner.
Calibrate the tester according to the manufactur-
er's instructions. The shop air source for testing
should maintain 483 kPa (70 psi) minimum, 1,379
kPa (200 psi) maximum and 552 kPa (80 psi) recom-
mended.
Perform the test procedure on each cylinder accord-
ing to the tester manufacturer's instructions. While
testing, listen for pressurized air escaping through
the throttle body, tailpipe or oil filler cap opening.
Check for bubbles in the radiator coolant.
All gauge pressure indications should be equal,
with no more than 25% leakage.
FOR EXAMPLE:At 552 kPa (80 psi) input pres-
sure, a minimum of 414 kPa (60 psi) should be main-
tained in the cylinder CYLINDER COMBUSTION
PRESSURE LEAKAGE DIAGNOSIS CHART .
CYLINDER COMBUSTION PRESSURE LEAKAGE DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
AIR ESCAPES THROUGH
THROTTLE BODYIntake valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
TAILPIPEExhaust valve bent, burnt, or not
seated properlyInspect valve and valve seat.
Reface or replace, as necessary
AIR ESCAPES THROUGH
RADIATORHead gasket leaking or cracked
cylinder head or blockRemove cylinder head and inspect.
Replace defective part
MORE THAN 50% LEAKAGE
FROM ADJACENT CYLINDERSHead gasket leaking or crack in
cylinder head or block between
adjacent cylindersRemove cylinder head and inspect.
Replace gasket, head, or block as
necessary
MORE THAN 25% LEAKAGE AND
AIR ESCAPES THROUGH OIL
FILLER CAP OPENING ONLYStuck or broken piston rings;
cracked piston; worn rings and/or
cylinder wallInspect for broken rings or piston.
Measure ring gap and cylinder
diameter, taper and out-of-round.
Replace defective part as necessary
9 - 8 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)