2003 JEEP GRAND CHEROKEE crankshaft

ENGINE CONTROL MODULE C1 (DIESEL) - BLACK 81 WAY
CAV CIRCUIT FUNCTION
1 Z108 14BK/DG GROUND
2 Z108 14BK/DG GROUND
3 K20 14DB GENERATOR FIELD CONTROL
4 F142 14RD/DG FUSED AUTO SHUT DOWN RELAY OUTPUT
5 F142 14RD/DG FUSED AUTO SHUT DOWN RELAY OUTPUT
6 D52 18DG/WT CAN C BUS(+)
7 D25 20VT/YL PCI BUS
8 K944 20BR/DG CAMSHAFT POSITION SENSOR GROUND
9 K44 20YL/GY CAMSHAFT POSITION SENSOR SIGNAL
10 - -
11 Y53 20BK/YL BOOST PRESSURE SENSOR SIGNAL
12 K155 20YL/WT MASS AIR FLOW SENSOR SIGNAL
13 Y40 20DG/VT FUEL PRESSURE SENSOR SIGNAL
14 K22 20RD/DB ACCELERATOR PEDAL POSITION SENSOR 2 SIGNAL
15 K81 20DB/DG ACCELERATOR PEDAL POSITION SENSOR 1 SIGNAL
16 Y100 20BR/GY FUEL PRESSURE SENSOR GROUND
17 - -
18 - -
19 F300 20RD/BK BATTERY SENSE (+)
20 Z11 20BK/WT BATTERY SENSE (-)
21 K4 18BK/LB SENSOR GROUND
22 F991 20RD/DB FUSED IGNITION SWITCH OUTPUT (RUN-START)
23 K6 18VT/WT SENSOR REFERENCE VOLTAGE B
24 K3 20BK CRANKSHAFT POSITION SENSOR SIGNAL 1
25 D51 18WT CAN C BUS(-)
26 - -
27 - -
28 - -
29 K77 20BR/WT TRANSFER CASE POSITION SENSOR INPUT
30 G60 20BR/DB ENGINE OIL PRESSURE SENSOR SIGNAL
31 - -
32 K25 20VT/DG BATTERY TEMPERATURE SENSOR SIGNAL
33 - -
34 K255 20WT/DG ACCELERATOR PEDAL POSITION SENSOR 1 GROUND
35 Y43 20WT/VT ACCELERATOR PEDAL POSITION SENSOR 1 5-VOLT
SUPPLY
36 C18 20DB A/C PRESSURE SENSOR SIGNAL
37 - -
38 V37 20RD/DG SPEED CONTROL SWITCH SIGNAL
39 K226 20DB/WT FUEL LEVEL SENSOR SIGNAL
40 K2 20DG/RD ENGINE COOLANT TEMPERATURE SENSOR SIGNAL
41 K21 20DG/WT INTAKE AIR TEMPERATURE SENSOR SIGNAL
42 Y101 20 CRANKSHAFT POSITION SENSOR SHIELD
43 K924 20YL CRANKSHAFT POSITION SENSOR SIGNAL 2
44 - -
45 - -
46 - -
47 L50 20WT/DB PRIMARY BRAKE SWITCH SIGNAL
48 K29 20WT/PK SECONDARY BRAKE SWITCH SIGNAL
49 - -
50 F855 18BR/YL SENSOR REFERENCE VOLTAGE A
51 - -
52 - -
53 - -
54 Z189 20BR MASS AIR FLOW SENSOR GROUND
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 75

POWER CONNECTOR - WHITE 2 WAY
CAV CIRCUIT FUNCTION
1 F85 16VT/WT FUSED B(+)
2 Z234 16BK GROUND
POWERTRAIN CONTROL MODULE C1 (GAS) - BLACK 32 WAY
CAV CIRCUIT FUNCTION
1 K93 14TN/OR COIL DRIVER NO. 3
2 F991 18OR/DB FUSED IGNITION SWITCH OUTPUT (RUN-START)
3 K94 14TN/LG (4.7L) COIL DRIVER NO. 4
4 K4 18BK/LB SENSOR GROUND
5 K96 14TN/LB (4.7L) COIL DRIVER NO. 6
6 T41 18BK/WT PARK/NEUTRAL POSITION SWITCH SENSE (T41)
7 K91 14TN/RD COIL DRIVER NO. 1
8 K24 18GY/BK CRANKSHAFT POSITION SENSOR SIGNAL
9 K98 14LB/RD (4.7L) COIL DRIVER NO. 8
10 K60 18YL/BK IDLE AIR CONTROL NO. 2 DRIVER
11 K40 18BR/WT IDLE AIR CONTROL NO. 3 DRIVER
12 - -
13 - -
14 K77 18LG/BK TRANSFER CASE POSITION SENSOR INPUT
15 K21 18BK/RD INTAKE AIR TEMPERATURE SENSOR SIGNAL
16 K2 18TN/BK ENGINE COOLANT TEMPERATURE SENSOR SIGNAL
17 K7 18OR 5 VOLT SUPPLY
18 K44 18TN/YL CAMSHAFT POSITION SENSOR SIGNAL
19 K39 18GY/BK IDLE AIR CONTROL NO. 1 DRIVER
20 K59 18VT/BK IDLE AIR CONTROL NO. 4 DRIVER
21 K95 14TN/DG (4.7L) COIL DRIVER NO. 5
22 A7 14RD/BK FUSED B(+)
23 K22 18OR/RD THROTTLE POSITION SENSOR SIGNAL
24 K41 18BK/DG OXYGEN SENSOR 1/1 SIGNAL
25 K141 18TN/WT OXYGEN SENSOR 1/2 SIGNAL
26 K241 18LG/RD (EXCEPT 4.0L
BUILT-UP-EXPORT)OXYGEN SENSOR 2/1 SIGNAL
27 K1 18DG/RD MAP SENSOR SIGNAL
28 - -
29 K341 18TN/WT (4.0L EXCEPT
BUILT-UP-EXPORT)OXYGEN SENSOR 2/2 SIGNAL
29 K341 18PK/WT (4.7L) OXYGEN SENSOR 2/2 SIGNAL
30 - -
31 Z82 14BK/WT GROUND
32 Z81 14BK/TN GROUND
8W - 80 - 108 8W-80 CONNECTOR PIN-OUTWJ

TRANSMISSION CONTROL MODULE (4.7L) - BLACK 60 WAY
CAV CIRCUIT FUNCTION
1 T1 18LG/BK TRS T1 SENSE
2 T2 18TN/BK TRS T2 SENSE
3 T3 18VT TRS T3 SENSE
4- -
5- -
6 K24 18GY/BK CRANKSHAFT POSITION SENSOR SIGNAL
7 D21 18PK SCI TRANSMIT
8 F45 18YL/RD FUSED IGNITION SWITCH OUTPUT (START)
9 T9 18OR/BK OVERDRIVE PRESSURE SWITCH SENSE
10 T10 18YL/DG TORQUE MANAGEMENT REQUEST SENSE
11 F991 18OR/DB FUSED IGNITION SWITCH OUTPUT (RUN-START)
12 K22 18OR/RD THROTTLE POSITION SENSOR SIGNAL
13 T13 18DB/BK SPEED SENSOR GROUND
14 T14 18LG/WT OUTPUT SPEED SENSOR SIGNAL
15 K30 18PK/YL TRANSMISSION CONTROL RELAY CONTROL
16 T16 14RD TRANSMISSION CONTROL RELAY OUTPUT
17 T16 14RD TRANSMISSION CONTROL RELAY OUTPUT
18 T118 18YL/DB PRESSURE CONTROL SOLENOID CONTROL
19 T119 18WT/DB 2C SOLENOID CONTROL
20 T120 18LG LR SOLENOID CONTROL
21 - -
22 - -
23 - -
24 - -
25 - -
26 - -
27 - -
28 - -
29 T29 18GY UNDERDRIVE PRESSURE SWITCH SENSE
30 T130 14VT/TN LINE PRESSURE SENSOR SIGNAL
31 - -
32 - -
33 - -
34 - -
35 - -
36 T16 14RD TRANSMISSION CONTROL RELAY OUTPUT
37 Z113 14BK/WT GROUND
38 T138 14GY/LB 5 VOLT SUPPLY
39 Z112 14BK/YL GROUND
40 T140 18VT/LG MS SOLENOID CONTROL
41 T41 18WT TRS T41 SENSE
42 T42 18VT/WT TRS T42 SENSE
43 D25 18YL/VT PCI BUS
44 - -
45 - -
46 D20 18LG SCI RECEIVE
47 T147 18LB 2C PRESSURE SWITCH SENSE
48 T48 18DB 4C PRESSURE SWITCH SENSE
49 T6 18VT/WT OVERDRIVE OFF SWITCH SENSE
50 T150 18BR/LB LR PRESSURE SWITCH SENSE
51 K4 18BK/LB SENSOR GROUND
52 T52 18RD/BK INPUT SPEED SENSOR SIGNAL
53 Z114 14BK/LG GROUND
54 T54 18VT TRANSMISSION TEMPERATURE SENSOR SIGNAL
55 T59 18PK UNDERDRIVE SOLENOID CONTROL
56 A30 14RD/WT FUSED B(+)
57 Z12 14BK/TN GROUND
58 - -
59 T159 18DG/WT 4C SOLENOID CONTROL
60 T60 18BR OVERDRIVE SOLENOID CONTROL
8W - 80 - 124 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)

SPLICES
SPLICE
NUMBERLOCATION FIG.
S100 Near T/O for Power Distribution Center Eyelet 2
S102 (4.0L) Near T/O for G103 10, 11
102 (4.7L) Near T/O for Fuel Injector No. 1 13
S102 (Diesel) Near T/O for C110 7, 8
S103 (4.7L) Near T/O for Engine Oil Pressure Sensor 13
S104 (4.0L) Near T/O for A/C Compressor Clutch N/S
S104 (4.7L) Near T/O for Oxygen Sensor 2/2 Downstream N/S
S105 (4.0L) Near T/O for Capacitor 10 11
S105 (4.7L) Near T/O for Fuel Injector NO. 7 13
S106 (4.0L) In T/O for Oxygen Sensors 11, 12
S106 (4.7L) Near T/O for C103 14
S106 (4.7L) RHD Near T/O for Fuel Injector No.4 15
S107 (4.0L) Near T/O for Fuel Injector No.5 9
S107 (4.7L) Near T/O for Fuel Injector No.7 13
S109 (4.0L) Near T/O for Fuel Injector No.2 9
S109 (4.7L) Near T/O for Coil On Plug No. 6 14, 15
S110 (4.0L
Except
Built-Up-Export)Near T/O for Oxygen Sensor N/S
S111 (4.7L) In T/O for Oxygen Sensor N/S
S111 (4.0L
Except
Built-Up-Export)Near T/O for Oxygen Sensor N/S
S112 (4.0L) Near T/O for C102, C103 and C104 10, 11
S112 (4.7L) Near T/O for Coil On Plug No.8 15
S112 (Diesel) Near T/O for Accelerator Pedal Position Sensor N/S
S113 (4.7L) Near T/O for Transmission Control Module 15, 18
S114 (4.0L) Near T/O for Transmission Control Module 18
S114 (4.7L) Near T/O for Transmission Control Module 15, 18
S115 (4.0L) Near T/O for Transmission Control Module 18
S115 (4.7L) Near T/O for Transmission Control Module 15, 18
S116 (4.0L) Near Powertrain Control Module C1 and C2 18
S116 (4.7L) LHD Near T/O for C102, C103 and C104 14
S116 (4.7L) RHD In T/O for Powertrain Control Module 15
S117 (4.7L) LHD Neat T/O for C102, C103 and C104 14
S118 (4.7L) Near T/O for Coil On PlugNo.4 14, 15
S118 (Diesel) Near T/O for Fuel Sender Unit N/S
S119 (4.7L) LHD In T/O for Crankshaft Position Sensor 18
S119 (4.7L) RHD In T/O for Powertrain Control Module 15
S120 (4.7L) Near T/O for Powertrain Control Module 15, 18
S121 (4.7L) Near T/O for Idle Air Control Motor 13
8W - 91 - 12 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONWJ
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

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

DIAGNOSIS AND TESTINGÐ ENGINE DIAGNOSIS - MECHANICAL
ENGINE MECHANICAL DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
NOISY VALVES/LIFTERS 1. High or low oil level in crankcase 1. Check for correct oil level. Adjust
oil level by draining or adding as
needed
2. Thin or diluted oil 2. Change oil. (Refer to 9 -
ENGINE/LUBRICATION/OIL -
STANDARD PROCEDURE)
3. Low oil pressure 3. Check engine oil level. If ok,
Perform oil pressure test. (Refer to 9
- ENGINE/LUBRICATION -
DIAGNOSIS AND TESTING) for
engine oil pressure test/specifications
4. Dirt in tappets/lash adjusters 4. Clean/replace hydraulic tappets/
lash adjusters
5. Bent push rod(s) 5. Install new push rods
6. Worn rocker arms 6. Inspect oil supply to rocker arms
and replace worn arms as needed
7. Worn tappets/lash adjusters 7. Install new hydraulic tappets/lash
adjusters
8. Worn valve guides 8. Inspect all valve guides and
replace as necessary
9. Excessive runout of valve seats or
valve faces9. Grind valves and seats
CONNECTING ROD NOISE 1. Insufficient oil supply 1. Check engine oil level.
2. Low oil pressure 2. Check engine oil level. If ok,
Perform oil pressure test. (Refer to 9
- ENGINE/LUBRICATION -
DIAGNOSIS AND TESTING) engine
oil pressure test/specifications
3. Thin or diluted oil 3. Change oil to correct viscosity.
(Refer to 9 - ENGINE/LUBRICATION/
OIL - STANDARD PROCEDURE) for
correct procedure/engine oil
specifications
4. Excessive connecting rod bearing
clearanceMeasure bearings for correct
clearance with plasti-gage. Repair as
necessary
5. Connecting rod journal out of
round5. Replace crankshaft or grind
journals
6. Misaligned connecting rods 6. Replace bent connecting rods
MAIN BEARING NOISE 1. Insufficient oil supply 1. Check engine oil level.
2. Low oil pressure 2. Check engine oil level. If ok,
Perform oil pressure test. (Refer to 9
- ENGINE/LUBRICATION -
DIAGNOSIS AND TESTING)
9 - 6 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
3. Thin or diluted oil 3. Change oil to correct viscosity.
4. Excessive main bearing clearance 4. Measure bearings for correct
clearance. Repair as necessary
5. Excessive end play 5. Check crankshaft thrust bearing for
excessive wear on flanges
6. Crankshaft main journal out of
round or worn6. Grind journals or replace
crankshaft
7. Loose flywheel or torque converter 7. Inspect crankshaft, flexplate/
flywheel and bolts for damage.
Tighten to correct torque
LOW OIL PRESSURE 1. Low oil level 1. Check oil level and fill if necessary
2. Faulty oil pressure sending unit 2. Install new sending unit
3. Clogged oil filter 3. Install new oil filter
4. Worn oil pump 4. Replace oil pump assembly.
5. Thin or diluted oil 5. Change oil to correct viscosity.
6. Excessive bearing clearance 6. Measure bearings for correct
clearance
7. Oil pump relief valve stuck 7. Remove valve to inspect, clean
and reinstall
8. Oil pump suction tube loose,
broken, bent or clogged8. Inspect suction tube and clean or
replace if necessary
9. Oil pump cover warped or cracked 9. Install new oil pump
OIL LEAKS 1. Misaligned or deteriorated gaskets 1. Replace gasket
2. Loose fastener, broken or porous
metal part2. Tighten, repair or replace the part
3. Front or rear crankshaft oil seal
leaking3. Replace seal
4. Leaking oil gallery plug or cup
plug4. Remove and reseal threaded plug.
Replace cup style plug
EXCESSIVE OIL
CONSUMPTION OR SPARK
PLUGS OIL FOULED1. CCV System malfunction 1. (Refer to 25 - EMISSIONS
CONTROL/EVAPORATIVE
EMISSIONS - DESCRIPTION) for
correct operation
2. Defective valve stem seal(s) 2. Repair or replace seal(s)
3. Worn or broken piston rings 3. Hone cylinder bores. Install new
rings
4. Scuffed pistons/cylinder walls 4. Hone cylinder bores and replace
pistons as required
5. Carbon in oil control ring groove 5. Remove rings and de-carbon
piston
6. Worn valve guides 6. Inspect/replace valve guides as
necessary
7. Piston rings fitted too tightly in
grooves7. Remove rings and check ring end
gap and side clearance. Replace if
necessary
WJENGINE - 4.0L 9 - 7
ENGINE - 4.0L (Continued)