2002 JEEP GRAND CHEROKEE Park

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Left Front Park/Turn Signal
Lamp (Except Built-Up-Export)BK At Lamp N/S
Left Front Side Marker Lamp
(Except Built-Up-Export)WT At Lamp N/S
Left Front Turn Signal Lamp
(Built-Up-Export)WT At Lamp N/S
Left Front Wheel Speed
SensorGY At Left Front Wheel Opening 4
Left Headlamp Leveling Motor
(Built-Up-Export)BK At Motor N/S
Left High Beam Headlamp BK At Lamp N/S
Left Instrument Panel Speaker WT At Speaker 19, 20
Left Liftgate Ajar Switch BK In Liftgate 38
Left Low Beam Headlamp GY At Lamp N/S
Left Multi-Function Switch WT On Steering Column 23
Left Rear Door Lock Motor/Ajar
SwitchBK In Left Rear Door 28
Left Rear Door Speaker WT In Left Rear Door 28
Left Rear Lamp Assembly BK At Lamp Assembly 37
Left Rear Wheel Speed Sensor GY Near Left Rear Wheel 33, 35
Left Remote Radio Switch BK At Switch in Steering Wheel N/S
Left Side Impact Sensor BK Left Body N/S
Left Side Repeater Lamp
(Built-Up-Export)BK On Left Front Fender 3, 4
Left Visor/Vanity Lamp BK At Lamp N/S
License Lamp No.1 BK At Lamp N/S
License Lamp No.2 BK At Lamp N/S
Liftgate Flip-Up Ajar Switch GY In Liftgate 38
Liftgate Flip-Up Push Button
SwitchBK In Liftgate N/S
Liftgate Flip-Up Release
SolenoidBK In Liftgate 38
Liftgate Lock Motor BK In Liftgate 38
Line Pressure Sensor (4.7L) BK Rear of Transmission N/S
Manifold Absolute Pressure
Sensor (4.0L)BK At Throttle Body 9
Manifold Absolute Pressure
Sensor (4.7L)BK Right Side of Engine 13
Manual Temperature Control -
C1 (MTC)WT Center of Instrument Panel N/S
Manual Temperature Control -
C2 (MTC)WT Center of Instrument Panel N/S
Mass Air Flow sensor (Diesel) BK Near T/O for G105 8
Mode Door Motor/Actuator
(AZC)BK Right Center of Instrument Panel N/S
WJ8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 7
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Output Speed Sensor (4.0L) GY Left Side of Transmission 12
Output Speed Sensor (4.7L) BK Left Side of Transmission 16
Overhead Map/Courtesy Lamp WT At Overhead Console N/S
Oxygen Sensor 1/1 Upstream
(4.0L)GY Left Side of Engine at Exhaust 9, 12
Oxygen Sensor 1/1 Upstream
(4.7L)GY Left Side of Engine at Exhaust 17
Oxygen Sensor 1/2
Downstream (4.0L)BK Rear of Transmission 9, 12
Oxygen Sensor 1/2
Downstream (4.7L)BK Rear of Transmission 17
Oxygen Sensor 2/1 Upstream Rear of Transmission N/S
Oxygen Sensor 2/2
DownstreamRear of Transmission N/S
Park Brake Switch Center Console Area, Near Airbag
Control Module20, 21, 22
Park/Neutral Position Switch
(4.0L)BK Left Side of Transmission 12
Park/Neutral Position Switch
(Diesel)BK Left Side of Transmission N/S
Passenger Airbag YL Passenger Side of Instrument Panel 19, 20
Passenger Blend Door
Motor/Actuator (AZC)BK Passenger Side of Instrument Panel N/S
Passenger Door Lock
Motor/Ajar SwitchBK In Passenger Door 26, 27
Passenger Door Module - C1 WT In Passenger Door 26, 27
Passenger Door Module - C2 BK In Passenger Door N/S
Passenger Front Door
Courtesy LampBK In Passenger Door N/S
Passenger Front Power
Window MotorBK In Passenger Door 26, 27
Passenger Heated Seat Back
(Premium I/III)GN At Passenger Seat N/S
Passenger Heated Seat
Cushion (Premium I/III)BK At Passenger Seat N/S
Passenger Heated Seat Switch BK Center of Instrument Panel 19, 20, 21
Passenger Lumbar Motor
(Midline/Premium)BK At Passenger Seat N/S
Passenger Lumbar Switch
(Midline/Premium)WT At Passenger Seat N/S
Passenger Power Mirror BK In Passenger Door N/S
Passenger Power Seat Front
Riser MotorRD At Passenger Seat N/S
Passenger Power Seat
Horizontal MotorRD At Passenger Seat N/S
8W - 91 - 8 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONWJ
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Passenger Power Seat Rear
Riser MotorRD At Passenger Seat N/S
Passenger Power Seat
Recliner Motor (Midline/
Premium)BK At Passenger Seat N/S
Passenger Power Seat Switch
(Midline/Premium)GN At Passenger Seat N/S
Passenger Rear Power
Window MotorBK In Right Rear Door 29
Passenger Rear Power
Window SwitchBL In Right Rear Door 29
Passenger Seat Belt Switch t Switch N/S
Power Amplifier - C1 WT Under Rear Seat 34, 36
Power Amplifier - C2 WT Under Rear Seat 34, 36
Power Connector WT Center of Instrument Panel 21, 22
Powertrain Control Module -
C1 (Gas)BK Rear of Engine Compartment 5, 10, 11, 14, 15, 18
Powertrain Control Module -
C2 (Gas)WT Rear of Engine Compartment 5, 10, 11, 14, 15, 18
Powertrain Control Module -
C3 (Gas)WT Rear of Engine Compartment N/S
Radiator Fan Motor BK At Radiator 5
Radiator Fan Relay BK Right Side of Engine Compartment 5
Radio - C1 GY Center of Instrument Panel 19, 20
Radio - C2 BK Center of Instrument Panel 19, 20
Rain Sensor BK Front Center Overhead N/S
Rear Power Outlet RD Right Rear Quarter Panel 37
Rear Washer Pump BK Left Front of Engine Compartment 3, 4
Rear Window Defogger BK Right Upper Coner of Liftgate 38
Rear Wiper Motor BK In Liftgate 38
Recirculation Door Motor/
Actuator (AZC)BK Center of Instrument Panel N/S
Red Brake Warning Indicator
SwitchGY At Master Cylinder 4
Remote Keyless Module
(Japan)BL In Driver Door 25
Right Courtesy Lamp BK At Lamp 20 21, 22
Right Curtain Airbag BK Near Right C Pillar 37
Right Door Handle Courtesy
LampBK At Lamp N/S
Right Fog Lamp BK At Right Front Fascia 5
Right Front Door Speaker WT In Right Front Door 25, 26
Right Front Impact Sensor BK Near Right Verticle Radiator Support N/S
Right Front Park Lamp WT At Lamp N/S
WJ8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 9
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Right Front Park/Turn Signal
Lamp (Except Built-Up-Export)BK At Lamp N/S
Right Front Side Marker Lamp
(Except Built-Up-Export)WT At Lamp N/S
Right Front Turn Signal Lamp
(Built-Up-Export)WT At Lamp N/S
Right Front Wheel Speed
SensorGY In Right Front Wheel Opening N/S
Right Headlamp Leveling
Motor (Built-Up-Export)BK At Motor N/S
Right High Beam Headlamp BK At Lamp N/S
Right Instrument Panel
SpeakerWT At Speaker 19, 20
Right Liftgate Ajar Switch BK In Liftgate 38
Right Low Beam Headlamp GY At Lamp N/S
Right Multi-Function Switch WT On Steering Column 23
Right Rear Door Lock
Motor/Ajar SwitchBK In Right Rear Door 29
Right Rear Door Speaker WT In Right Rear Door 29
Right Rear Lamp Assembly BK At Lamp Assembly 37
Right Rear Wheel Speed
SensorBK Near Right Rear Wheel 33, 35
Right Remote Radio Switch BK At Switch in Steering Wheel N/S
Right Side Repeater Lamp
(Built-Up-Export)BK On Right Front Fender 5
Right Visor/Vanity Lamp BK At Lamp N/S
Seat Belt Switch WT At Driver Seat N/S
Seat Module - C1 (Premium) BK Under Driver Seat N/S
Seat Module - C2 (Premium) OR Under Driver Seat N/S
Sentry Key Immobilizer Module BK On Steering Column 23
Shifter Assembly (Gas) WT Between Front Seats 23
Shifter Assembly C1 (Diesel) Between Front Seats N/S
Shifter Assembly C2 (Diesel) Between Front Seats N/S
Siren (Built-up-export) Left Front Fender 3, 4
Speed Control Switch NO. 1 BK On Steering Wheel N/S
Speed Control Switch NO. 2 BK On Steering Wheel N/S
Sunroof Control Module At Sunroof 32
Sunroof Motor C1 WT At Sunroof N/S
Sunroof Motor C2 BK In Overhead N/S
Sunroof Switch GY At Switch N/S
Temperature Valve Actuator
(MTC)BK On HVAC Housing N/S
Throttle Position Sensor (4.0L) BK Left Side of Engine 9
Throttle Position Sensor (4.7L) WT Left Side of Engine 13
8W - 91 - 10 8W-91 CONNECTOR/GROUND/SPLICE LOCATIONWJ
CONNECTOR/GROUND/SPLICE LOCATION (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)

CONDITION POSSIBLE CAUSES CORRECTION
3. Worn or incorrect gapped spark
plugs3. Clean plugs and set gap. (Refer to
8 - ELECTRICAL/IGNITION
CONTROL/SPARK PLUG -
CLEANING).
4. Dirt or water in fuel system 4. Clean system and replace fuel
filter
5. Faulty fuel pump 5. Install new fuel pump
6. Incorrect valve timing 6. Correct valve timing
7. Blown cylinder head gasket 7. Install new cylinder head gasket
8. Low compression 8. Test cylinder compression. (Refer
to 9 - ENGINE - DIAGNOSIS AND
TESTING).
9. Burned, warped, or pitted valves 9. Install/Reface valves as necessary
10. Plugged or restricted exhaust
system10. Install new parts as necessary
11. Faulty ignition coil rail 11. Test and replace, as necessary.
(Refer to 8 - ELECTRICAL/IGNITION
CONTROL/COIL RAIL - REMOVAL).
ENGINE STALLS OR ROUGH
IDLE1. Carbon build-up on throttle plate 1. Remove throttle body and
de-carbon. (Refer to 14 - FUEL
SYSTEM/FUEL INJECTION/
THROTTLE BODY - REMOVAL) for
correct procedure.
2. Engine idle speed too low 2. Check Idle Air Control circuit.
3. Worn or incorrectly gapped spark
plugs3. Replace or clean and re-gap spark
plugs. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING)
4. Faulty coil rail 4. Test and replace, if necessary.
(Refer to 8 - ELECTRICAL/IGNITION
CONTROL/COIL RAIL - REMOVAL)
5. Intake manifold vacuum leak 5. Inspect intake manifold gasket and
vacuum hoses. Replace if necessary.
(Refer to 9 - ENGINE/MANIFOLDS/
INTAKE MANIFOLD - DIAGNOSIS
AND TESTING).
ENGINE MISSES ON
ACCELERATION1. Worn or incorrectly gapped spark
plugs1. Replace spark plugs or clean and
set gap.
2. Spark plug cables defective or
crossed2. Replace spark plug cables.
3. Dirt in fuel system 3. Clean fuel system
4. Burned, warped or pitted valves 4. Install new valves
5. Faulty coil rail 5. Test and replace as necessary.
(Refer to 8 - ELECTRICAL/IGNITION
CONTROL/COIL RAIL - REMOVAL)
WJENGINE - 4.0L 9 - 5
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)

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)