2003 JEEP GRAND CHEROKEE Oil pressure switch

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

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)

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)

(7) Remove the fan assembly from the water pump
(Refer to 7 - COOLING/ENGINE/RADIATOR FAN -
REMOVAL).
(8) Remove the fan shroud.
(9) Disconnect the transmission fluid cooler lines
(automatic transmission).
(10) Discharge the A/C system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
(11) Remove the service valves and cap the com-
pressor ports.
(12) Remove the radiator or radiator/condenser (if
equipped with A/C).
(13) Disconnect the heater hoses at the engine
thermostat housing and water pump.
(14) Disconnect the accelerator cable, transmission
line pressure cable and speed control cable (if
equipped) from the throttle body.
(15) Remove cables from the bracket and secure
out of the way.
(16) Disconnect the body ground at the engine.
(17) Disconnect the following connectors and
secure their harness out of the way.
²Power steering pressure switch
²Coolant temperature sensor
²Six (6) fuel injector connectors
²Intake air temperature sensor
²Throttle position sensor
²Map sensor
²Crankshaft position sensor
²Oxygen sensor
²Camshaft position sensor
²Generator connector and B+ terminal wire
(18) Disconnect the coil rail electrical connections
and the oil pressure switch connector.
(19) Perform the fuel pressure release procedure
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
STANDARD PROCEDURE).
(20) Disconnect the fuel supply line at the injector
rail (Refer to 14 - FUEL SYSTEM/FUEL DELIVERY/
QUICK CONNECT FITTING - STANDARD PROCE-
DURE).
(21) Remove the fuel line bracket from the intake
manifold.
(22) Remove the air cleaner assembly (Fig. 5).
(23) Disconnect the hoses from the fittings at the
steering gear.
(24) Drain the pump reservoir.
(25) Cap the fittings on the hoses and steering
gear to prevent foreign objects from entering the sys-
tem.
(26) Raise and support the vehicle.
(27) Disconnect the wires from the engine starter
motor solenoid.(28) Remove the engine starter motor (Refer to 8 -
ELECTRICAL/STARTING/STARTER MOTOR -
REMOVAL).
(29) Disconnect the oxygen sensor from the
exhaust pipe.
(30) Disconnect the exhaust pipe from the mani-
fold.
(31) Remove the exhaust pipe support.
(32) Remove the bending brace (Refer to 9 -
ENGINE/ENGINE BLOCK/STRUCT SUPPORT -
REMOVAL).
(33) Remove the engine flywheel/converter housing
access cover.
(34) Mark the converter and drive plate location.
(35) Remove the converter-to-drive plate bolts.
(36) Remove the upper engine flywheel/converter
housing bolts and loosen the bottom bolts.
(37) Remove the engine mount cushion-to-engine
compartment bracket bolts.
(38) Lower the vehicle.
(39) Attach a lifting device to the engine.
(40) Raise the engine off the front supports.
(41) Place a support or floor jack under the con-
verter (or engine flywheel) housing.
(42) Remove the remaining converter (or engine
flywheel) housing bolts.
(43) Lift the engine out of the engine compart-
ment.
Fig. 5 Air Cleaner Assembly
1 - POWER STEERING PUMP
2 - AIR CLEANER ASSEMBLY
9 - 12 ENGINE - 4.0LWJ
ENGINE - 4.0L (Continued)

INSTALLATION
CAUTION: When installing the engine into a vehicle
equipped with an automatic transmission, be care-
ful not to damage the trigger wheel on the engine
flywheel.
(1) Attach a lifting device to the engine and lower
the engine into the engine compartment. For easier
installation, it may be necessary to remove the
engine mount bracket as an aid in alignment of the
engine to the transmission.
(2) Align the transmission torque converter hous-
ing with the engine.
(3) Loosely install the converter housing lower
bolts and install the next higher bolt and nut on each
side.
(4) Tighten all 4 bolts finger tight.
(5) Install the engine mount brackets (if removed).
(6) Lower the engine and engine mount brackets
onto the engine compartment cushions. Install the
bolts and finger tighten the nuts.
(7) Remove the engine lifting device.
(8) Raise and support the vehicle.
(9) Install the remaining engine flywheel/converter
housing bolts. Tighten all bolts to 38 N´m (28 ft. lbs.)
torque.
(10) Install the converter-to-drive plate bolts.
(11) Ensure the installation reference marks are
aligned.
(12) Install the engine flywheel/converter housing
access cover.
(13) Install the exhaust pipe support and tighten
the screw.
(14) Install the engine bending brace (Refer to 9 -
ENGINE/ENGINE BLOCK/STRUCT SUPPORT -
INSTALLATION).
(15) Tighten the engine mount-to-bracket bolts.
(16) Connect the vehicle speed sensor wire connec-
tions and tighten the screws.
(17) Connect the exhaust pipe to the manifold.
(18) Install the engine starter motor (Refer to 8 -
ELECTRICAL/STARTING/STARTER MOTOR -
INSTALLATION).
(19) Connect the wires to the engine starter motor
solenoid.
(20) Lower the vehicle.
(21) Connect all the vacuum hoses and wire con-
nectors identified during engine removal.
(22) Remove protective caps from the power steer-
ing hoses.
(23) Connect the hoses to the fittings at the steer-
ing gear. Tighten the nut to 52 N´m (38 ft. lbs.)
torque.
(24) Fill the pump reservoir with fluid.(25) Inspect the fuel supply line o-ring(s) and
replace if necessary. Connect fuel supply line to injec-
tior rail and verify connection by pulling outward on
the line.
(26) Install the fuel line bracket to the intake
manifold.
(27) Connect the coil rail electrical connectors and
oil pressure switch connector.
(28) Connect the following electrical connectors:
²Power steering pressure switch
²Coolant temperature sensor
²Six (6) fuel injector connectors
²Intake air temperature sensor
²Throttle position sensor
²Map sensor
²Crankshaft position sensor
²Oxygen sensor
²Camshaft position sensor
²Generator connector and B+ terminal wire
(29) Connect all previously removed vacuum hoses.
(30) Connect the body ground strap.
(31) Install the throttle, transmission line pres-
sure, and speed control cables to their mounting
bracket and connect them to the throttle body.
(32) Connect the heater hoses at the engine ther-
mostat housing and water pump.
(33) Install the fan assembly (Refer to 7 - COOL-
ING/ENGINE/RADIATOR FAN - INSTALLATION).
(34) Place the fan shroud in position over the fan.
(35) Install the radiator (Refer to 7 - COOLING/
ENGINE/RADIATOR - INSTALLATION).
(36) Connect the service valves to the A/C com-
pressor ports, if equipped with A/C.
(37) Charge the air conditioner system (Refer to 24
- HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
(38) Connect the radiator hoses and automatic
transmission fluid cooler pipes, if equipped.
(39) Install the fan shroud to the radiator or radi-
ator/condenser (if equipped with A/C).
(40) Install upper radiator support.
(41) Connect the upper radiator hose and tighten
the clamp.
(42) Connect the lower radiator hose and tighten
the clamp.
(43) Fill crankcase with engine oil. (Refer to
LUBRICATION & MAINTENANCE/FLUID CAPACI-
TIES - SPECIFICATIONS) for correct capacities.
(44) Fill the cooling system with reusable coolant
or new coolant (Refer to 7 - COOLING - STANDARD
PROCEDURE).
(45) Align the hood to the scribe marks. Install the
hood.
(46) Install the air cleaner assembly.
(47) Install the battery and connect the battery
cable.
WJENGINE - 4.0L 9 - 13
ENGINE - 4.0L (Continued)

ROCKER ARM / ADJUSTER ASSEMBLY
DESCRIPTION........................107
REMOVAL............................107
INSTALLATION........................107
VALVE SPRINGS
DESCRIPTION........................108
VALVE STEM SEALS
DESCRIPTION........................108
ENGINE BLOCK
DESCRIPTION........................108
STANDARD PROCEDUREÐCYLINDER BORE
HONING...........................108
CLEANING...........................109
INSPECTION.........................109
CONNECTING ROD BEARINGS
STANDARD PROCEDURE - CONNECTING
ROD BEARING FITTING...............109
CRANKSHAFT
DESCRIPTION........................111
STANDARD PROCEDURE - MEASURING
CRANKSHAFT END PLAY..............111
REMOVAL............................112
INSPECTION..........................112
INSTALLATION........................112
CRANKSHAFT MAIN BEARINGS
STANDARD PROCEDUREÐCRANKSHAFT
MAIN BEARING - FITTING..............114
INSPECTION..........................115
CRANKSHAFT OIL SEAL - FRONT
REMOVAL............................115
INSTALLATION........................116
CRANKSHAFT OIL SEAL - REAR
REMOVAL............................117
INSTALLATION........................117
FLEX PLATE
REMOVAL............................118
INSTALLATION........................118
PISTON & CONNECTING ROD
DESCRIPTION........................118
STANDARD PROCEDUREÐPISTON FITTING . 118
REMOVAL............................118
CLEANING...........................119
INSPECTION..........................119
INSTALLATION........................120
PISTON RINGS
STANDARD PROCEDURE - PISTON RING
FITTING............................121
VIBRATION DAMPER
REMOVAL............................122
INSTALLATION........................123
STRUCTURAL COVER
DESCRIPTION........................124
OPERATION..........................124
REMOVAL............................124
INSTALLATION........................124
FRONT MOUNT
REMOVAL............................124INSTALLATION........................125
REAR MOUNT
REMOVAL............................125
INSTALLATION........................126
LUBRICATION
DESCRIPTION........................126
OPERATION..........................126
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐENGINE OIL
PRESSURE.........................128
DIAGNOSIS AND TESTINGÐREAR SEAL
AREA LEAKS........................128
DIAGNOSIS AND TESTINGÐENGINE OIL
LEAK..............................129
OIL
STANDARD PROCEDURE - ENGINE OIL....130
OIL FILTER
REMOVAL............................131
INSTALLATION........................132
OIL PAN
DESCRIPTION........................132
REMOVAL............................132
CLEANING...........................132
INSPECTION.........................132
INSTALLATION........................132
OIL PRESSURE SENSOR/SWITCH
DESCRIPTION........................133
OPERATION..........................133
REMOVAL............................133
INSTALLATION........................133
OIL PUMP
REMOVAL............................134
DISASSEMBLY........................134
CLEANING...........................134
INSPECTION.........................134
ASSEMBLY...........................135
INSTALLATION........................135
INTAKE MANIFOLD
DESCRIPTION........................136
DIAGNOSIS AND TESTINGÐINTAKE
MANIFOLD LEAKAGE.................136
REMOVAL............................136
CLEANING...........................137
INSPECTION.........................137
INSTALLATION........................137
EXHAUST MANIFOLD - LEFT
DESCRIPTION........................138
REMOVAL............................138
CLEANING...........................138
INSPECTION.........................138
INSTALLATION........................138
EXHAUST MANIFOLD - RIGHT
DESCRIPTION........................139
REMOVAL............................139
CLEANING...........................140
INSPECTION.........................141
INSTALLATION........................141
9 - 62 ENGINE - 4.7LWJ

CONDITION POSSIBLE CAUSES CORRECTION
OIL PRESSURE DROP 1. Low oil level. 1. Check and correct oil level.
2. Faulty oil pressure sending unit. 2. Replace sending unit (Refer to 9 -
ENGINE/LUBRICATION/OIL
PRESSURE SENSOR/SWITCH -
REMOVAL).
3. Low oil pressure. 3. Check oil pump and bearing
clearance.
4. Clogged oil filter. 4. Replace oil filter (Refer to 9 -
ENGINE/LUBRICATION/OIL FILTER -
REMOVAL).
5. Worn oil pump. 5. Replace oil pump (Refer to 9 -
ENGINE/LUBRICATION/OIL PUMP -
REMOVAL).
6. Thin or diluted oil. 6. Change oil and filter.
7. Excessive bearing clearance. 7. Replace as necessary.
8. Oil pump relief valve stuck. 8. Replace oil pump (Refer to 9 -
ENGINE/LUBRICATION/OIL PUMP -
REMOVAL).
9. Oil pick up tube loose, damaged
or clogged.9. Replace as necessary.
OIL PUMPING AT RINGS;
SPARK PLUGS FOULING1. Worn or damaged rings. 1. Hone cylinder bores and replace
rings.
2. Carbon in oil ring slots. 2. Replace rings (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON
RINGS - STANDARD PROCEDURE).
3. Incorrect ring size installed. 3. Replace rings (Refer to 9 -
ENGINE/ENGINE BLOCK/PISTON
RINGS - STANDARD PROCEDURE).
4. Worn valve guides. 4. Ream guides and replace valves
(Refer to 9 - ENGINE/CYLINDER
HEAD/INTAKE/EXHAUST VALVES &
SEATS - STANDARD PROCEDURE).
5. Leaking valve guide seals. 5. Replace valve guide seals.
DIAGNOSIS AND TESTING - CYLINDER
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.
(3) Secure the throttle in the wide-open position.(4) Disable the fuel system (Refer to 14 - FUEL
SYSTEM/FUEL DELIVERY - DESCRIPTION).
(5) Remove the ASD relay (Refer to 8 - ELECTRI-
CAL/IGNITION CONTROL/AUTO SHUT DOWN
RELAY - REMOVAL).
(6) Insert a compression pressure gauge and rotate
the engine with the engine starter motor for three
revolutions.
(7) Record the compression pressure on the 3rd
revolution. Continue the test for the remaining cylin-
ders.
(8) (Refer to 9 - ENGINE - SPECIFICATIONS) for
the correct engine compression pressures.
9 - 68 ENGINE - 4.7LWJ
ENGINE - 4.7L (Continued)