2002 JEEP GRAND CHEROKEE oil pressure

ENGINE CONTROL MODULE C2 (DIESEL) - BLACK 40 WAY
CAV CIRCUIT FUNCTION
105 - -
106 - -
107 - -
108 - -
109 - -
110 - -
111 - -
112 T41 20BK/WT PARK/NEUTRAL POSITION SWITCH SENSE (T41)
113 - -
114 - -
115 K14 14BK/YL FUEL INJECTOR NO. 4 CONTROL
116 K63 14BK COMMON INJECTOR DRIVER
117 - -
118 K11 14BK/DB FUEL INJECTOR NO. 1 CONTROL
119 K38 14BK/DG FUEL INJECTOR NO. 5 CONTROL
120 K12 14BK/VT FUEL INJECTOR NO. 2 CONTROL
121 K13 14BK/RD FUEL INJECTOR NO. 3 CONTROL
ENGINE COOLANT TEMPERATURE SENSOR (DIESEL) - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 K4 20BK/LB SENSOR GROUND
2 K2 20DG/RD ENGINE COOLANT TEMPERATURE SENSOR SIGNAL
ENGINE COOLANT TEMPERATURE SENSOR (GAS) - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 K4 18BK/LB SENSOR GROUND
2 K2 18TN/BK ENGINE COOLANT TEMPERATURE SENSOR SIGNAL
ENGINE OIL PRESSURE SENSOR (DIESEL) - BLACK 3 WAY
CAV CIRCUIT FUNCTION
1 K6 18VT/WT SENSOR REFERENCE VOLTAGE B
2 G60 20BR/DB ENGINE OIL PRESSURE SENSOR SIGNAL
3 K4 18BK/LB SENSOR GROUND
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 77

ENGINE OIL PRESSURE SENSOR (GAS) - BLACK 3 WAY
CAV CIRCUIT FUNCTION
1 K6 18VT/BK 5 VOLT SUPPLY
2 G60 18GY/YL ENGINE OIL PRESSURE SENSOR SIGNAL
3 K4 18BK/LB SENSOR GROUND
EVAP/PURGE SOLENOID (GAS) - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 F12 20DB/WT FUSED IGNITION SWITCH OUTPUT (RUN-START)
2 K52 18PK/BK (RHD) DUTY CYCLE EVAP/PURGE SOLENOID CONTROL
2 K52 20PK/BK (LHD) DUTY CYCLE EVAP/PURGE SOLENOID CONTROL
FRONT POWER OUTLET - RED 3 WAY
CAV CIRCUIT FUNCTION
1 F85 16VT (RHD) FUSED B(+)
1 F85 16VT/WT (LHD) FUSED B(+)
2- -
3 Z300 16BK GROUND
FRONT WASHER PUMP - WHITE 2 WAY
CAV CIRCUIT FUNCTION
1 V10 20BR WASHER PUMP SWITCH SENSE
2 Z141 20BK GROUND
FRONT WIPER MOTOR - BLACK 6 WAY
CAV CIRCUIT FUNCTION
1 V6 16DB FUSED IGNITION SWITCH OUTPUT (RUN-ACC)
2 V55 16TN/RD WIPER PARK SWITCH SENSE
3- -
4 Z141 16BK GROUND
5 V3 16BR/WT WIPER HIGH/LOW RELAY LOW SPEED OUTPUT
6 V4 16RD/YL WIPER HIGH/LOW RELAY HIGH SPEED OUTPUT
8W - 80 - 78 8W-80 CONNECTOR PIN-OUTWJ

POWERTRAIN CONTROL MODULE C2 (GAS) - WHITE 32 WAY
CAV CIRCUIT FUNCTION
1 T54 18VT (4.0L) TRANSMISSION TEMPERATURE SENSOR SIGNAL
2 K26 18VT (4.7L) FUEL INJECTOR NO. 7 DRIVER
3- -
4 K11 18WT/DB FUEL INJECTOR NO. 1 DRIVER
5 K13 18YL/WT FUEL INJECTOR NO. 3 DRIVER
6 K38 18GY FUEL INJECTOR NO. 5 DRIVER
7 K97 14BR (4.7L) COIL DRIVER NO. 7
8 K88 18PK (4.0L) GOVERNOR PRESSURE SOLENOID CONTROL
9 K92 14TN/PK COIL DRIVER NO. 2
10 K20 18DG GENERATOR FIELD DRIVER
11 T20 18LB (4.0L) TORQUE CONVERTER CLUTCH SOLENOID CONTROL
12 K58 18BR/DB FUEL INJECTOR NO. 6 DRIVER
13 K28 18GY/LB (4.7L) FUEL INJECTOR NO. 8 DRIVER
14 - -
15 K12 18TN FUEL INJECTOR NO. 2 DRIVER
16 K14 18LB/BR FUEL INJECTOR NO. 4 DRIVER
17 K173 18LG RADIATOR FAN RELAY CONTROL
18 - -
19 C18 18DB A/C PRESSURE SIGNAL
20 - -
21 T60 18BR (4.0L) 3-4 SHIFT SOLENOID CONTROL
22 - -
23 G60 18GY/YL ENGINE OIL PRESSURE SENSOR SIGNAL
24 - -
25 T13 18DB/BK (4.0L) SPEED SENSOR GROUND
26 - -
27 B22 18DG/YL VEHICLE SPEED SENSOR SIGNAL
28 T14 18LG/WT (4.0L) OUTPUT SPEED SENSOR SIGNAL
29 T25 18LG/RD (4.0L) GOVERNOR PRESSURE SENSOR SIGNAL
30 K30 18PK/YL (4.0L) TRANSMISSION CONTROL RELAY CONTROL
31 K6 18VT/BK 5 VOLT SUPPLY
32 - -
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 109

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Driver Power Seat Horizontal
Motor Sensor (Premium II/III)BK At Driver Seat N/S
Driver Power Seat Rear Riser
MotorRD At Driver Seat N/S
Driver Power Seat Rear Riser
Motor Sensor (Premium II/III)BK At Driver Seat N/S
Driver Power Seat Recliner
MotorBK At Driver Seat N/S
Driver Power Seat Recliner
Motor Sensor (Premium II/III)BK At Driver Seat N/S
Driver Power Seat Switch
(Midline/Premium)GN At Driver Seat N/S
Driver Rear Power Window
MotorBK In Left Rear Door 28
Driver Rear Power Window
SwitchBL In Left Rear Door 28
Driver Seat Belt Switch At Switch N/S
EGR Solenoid (Diesel) BK Left Front Fender 7, 8
Electric Brake BL Near Junction Block N/S
Electronic Speed Control Servo BK Right Front of Engine Compartment 5
Engine Control Module C1
(Diesel)BK Left Front of Engine 7, 8
Engine Control Module C2
(Diesel)BK Left Front of Engine 7, 8
Engine Coolant Temperature
Sensor (Diesel)BK Top of Engine N/S
Engine Coolant Temperature
Sensor (GAS)BK Front of Engine 9, 13
Engine Oil Pressure Sensor BK Side of Engine 10, 11, 13
EVAP/Purge Solenoid BK Left Front Fender Near Controller
Antilock Brake3
Front Power Outlet RD Center of Instrument Panel 19, 20
Front Washer Pump WT Left Front of Engine Compartment 3, 4
Front Wiper Motor BK Left Side of Cowl 3, 4
Fuel Injector No.1 BK At Injector 7, 9, 13
Fuel Injector No.2 BK At Injector 7, 9, 14, 15
Fuel Injector No.3 BK At Injector 7, 9, 13
Fuel Injector No.4 BK At Injector 7, 9, 14, 15
Fuel Injector No.5 BK At Injector 9, 13
Fuel Injector No.6 BK At Injector 9, 14, 15
Fuel Injector No.7 (4.7L) BK At Injector 13
Fuel Injector No.8 (4.7L) BK At Injector 14, 15
Fuel Pressure Sensor (Diesel) BK Right Front of Engine N/S
Fuel Pressure Solenoid
(Diesel)BK Top of Engine N/S
WJ8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 5
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)

The cigar lighter 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 - POWER OUTLET
RELAY
The power outlet / cigar lighter relay (Fig. 16) is
located in the junction block, below the driver side
end of the instrument panel in the passenger com-
partment. For complete circuit diagrams, refer to
Horn/Cigar Lighter/Power Outletin Wiring Dia-
grams.
WARNING: REFER TO RESTRAINTS BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE
PROPER PRECAUTIONS COULD RESULT IN ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.
(1) Remove the power outlet / cigar lighter relay
from the junction block. Refer to the procedure in
this group.
(2) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 3. If not OK, replace the faulty relay.
(3) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   5 ohms. If OK, go to Step
4. If not OK, replace the faulty relay.
(4) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, perform the Relay Circuit Test that
follows. If not OK, replace the faulty relay.
DIAGNOSIS AND TESTING - RELAY CIRCUIT TEST
(1) The relay common feed terminal cavity (30) of
the junction block is connected to battery voltage and
should be hot at all times. Check for battery voltage
at the fused B(+) circuit cavity in the junction block
receptacle for the cigar lighter relay. If OK, go to
Step 2. If not OK, repair the fused B(+) circuit to the
Power Distribution Center (PDC) fuse as required.
(2) The relay normally closed terminal (87A) is
connected to terminal 30 in the de-energized position,
but is not used for this application. Go to Step 3.
(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the fused B(+) fuse in the junction block that feeds
the cigar lighter when the relay is energized by the
ignition switch. There should be continuity between
the junction block cavity for relay terminal 87 and
the fused B(+) fuse in the junction block at all times.
If OK, go to Step 4. If not OK, repair the open fused
B(+) circuit to the junction block fuse as required.
(4) The coil ground terminal (85) is connected to
the electromagnet in the relay. It receives battery
feed to energize the cigar lighter relay when the igni-
tion switch is in the Accessory or On positions. Turn
the ignition switch to the On position. Check for bat-
tery voltage at the fused ignition switch output (acc/
run) circuit cavity for relay terminal 85 in the
junction block receptacle for the cigar lighter relay. If
OK, go to Step 5. If not OK, repair the open fused
ignition switch output (acc/run) circuit to the ignition
switch as required.
(5) The coil battery terminal (86) is connected to
the electromagnet in the relay. The junction block
cavity for this terminal should have continuity to
Fig. 16 Accessory Relay
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
8W - 97 - 14 8W-97 POWER DISTRIBUTIONWJ
POWER OUTLET RELAY (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