2002 JEEP LIBERTY Spark plug

VEHICLE EMISSION CONTROL
INFORMATION (VECI) LABEL
DESCRIPTION
All models have a Vehicle Emission Control Infor-
mation (VECI) Label. DaimlerChrysler permanently
attaches the label in the engine compartment (Fig.
4). The label cannot be removed without defacing
label information and destroying label.
The label contains the vehicle's emission specifica-
tions and vacuum hose routings. All hoses must be
connected and routed according to the label.
The label also contains an engine vacuum sche-
matic. There are unique labels for vehicles built for
sale in the state of California and the country of
Canada. Canadian labels are written in both the
English and French languages.
The VECI label contains the following:
²Engine family and displacement
²Evaporative family
²Emission control system schematic
²Certification application
²Engine timing specifications (if adjustable)
²Idle speeds (if adjustable)
²Spark plug and gap
VEHICLE IDENTIFICATION
NUMBER
DESCRIPTION
The Vehicle Identification Number (VIN) plate is
located on the lower left A-pillar and is visible
through the windshield (Fig. 5). The VIN contains 17
characters that provide data concerning the vehicle.
Refer to the VIN decoding chart to determine the
identification of a vehicle.
The Vehicle Identification Number is also
imprinted on the:
²Vehicle Safety Certification Label.
²Frame rail.
To protect the consumer from theft and possible
fraud the manufacturer is required to include a
Check Digit at the ninth position of the Vehicle Iden-
tification Number. The check digit is used by the
manufacturer and government agencies to verify the
authenticity of the vehicle and official documenta-
tion. The formula to use the check digit is not
released to the general public.
Fig. 4 VECI LABEL LOCATION
1 - RADIATOR SUPPORT
2 - VECI LABEL
Fig. 5 VIN NUMBER LOCATION
1 - A-PILLAR
2 - VIN CODE PLATE
8 INTRODUCTIONKJ

the pan, it will drain first because it is heavier than
oil. An alternative method is to operate engine for a
short period to churn the oil. After this is done,
remove engine dipstick and inspect for water glob-
ules. Also inspect transmission dipstick for water
globules and transmission fluid cooler for leakage.
WARNING: WITH RADIATOR PRESSURE TESTER
TOOL INSTALLED ON RADIATOR, DO NOT ALLOW
PRESSURE TO EXCEED 124 KPA (18 PSI). PRES-
SURE WILL BUILD UP QUICKLY IF A COMBUSTION
LEAK IS PRESENT. TO RELEASE PRESSURE,
ROCK TESTER FROM SIDE TO SIDE. WHEN
REMOVING TESTER, DO NOT TURN TESTER MORE
THAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.
Operate engine without pressure cap on radiator
until thermostat opens. Attach a Pressure Tester to
filler neck. If pressure builds up quickly it indicates a
combustion leak exists. This is usually the result of a
cylinder head gasket leak or crack in engine. Repair
as necessary.
If there is not an immediate pressure increase,
pump the Pressure Tester. Do this until indicated
pressure is within system range of 110 kPa (16 psi).
Fluctuation of gauge pointer indicates compression or
combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic
converter,do notremove spark plug cables or short
out cylinders to isolate compression leak.
If the needle on dial of pressure tester does not
fluctuate, race engine a few times to check for an
abnormal amount of coolant or steam. This would be
emitting from exhaust pipe. Coolant or steam from
exhaust pipe may indicate a faulty cylinder head gas-
ket, cracked engine cylinder block or cylinder head.A convenient check for exhaust gas leakage into
cooling system is provided by a commercially avail-
able Block Leak Check tool. Follow manufacturers
instructions when using this product.
COMBUSTION LEAKAGE TEST - WITHOUT
PRESSURE TESTER
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE CYLINDER BLOCK
DRAIN PLUGS OR LOOSEN RADIATOR DRAIN-
COCK WITH SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
Drain sufficient coolant to allow thermostat
removal. (Refer to 7 - COOLING/ENGINE/ENGINE
COOLANT THERMOSTAT - REMOVAL). Remove
accessory drive belt (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - REMOVAL).
Add coolant to radiator to bring level to within 6.3
mm (1/4 in) of top of thermostat housing.
CAUTION: Avoid overheating. Do not operate
engine for an excessive period of time. Open drain-
cock immediately after test to eliminate boil over.
Start engine and accelerate rapidly three times, to
approximately 3000 rpm while observing coolant. If
internal engine combustion gases are leaking into
cooling system, bubbles will appear in coolant. If bub-
bles do not appear, internal combustion gas leakage
is not present.
KJCOOLING 7 - 5
COOLING (Continued)

WARNING: WITH RADIATOR PRESSURE TESTER
TOOL INSTALLED ON RADIATOR, DO NOT ALLOW
PRESSURE TO EXCEED 124 KPA (18 PSI). PRES-
SURE WILL BUILD UP QUICKLY IF A COMBUSTION
LEAK IS PRESENT. TO RELEASE PRESSURE,
ROCK TESTER FROM SIDE TO SIDE. WHEN
REMOVING TESTER, DO NOT TURN TESTER MORE
THAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.
Operate engine without pressure cap on radiator
until thermostat opens. Attach a Pressure Tester to
filler neck. If pressure builds up quickly it indicates a
combustion leak exists. This is usually the result of a
cylinder head gasket leak or crack in engine. Repair
as necessary.
If there is not an immediate pressure increase,
pump the Pressure Tester. Do this until indicated
pressure is within system range of 110 kPa (16 psi).
Fluctuation of gauge pointer indicates compression or
combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic
converter,do notremove spark plug cables or short
out cylinders to isolate compression leak.
If the needle on dial of pressure tester does not
fluctuate, race engine a few times to check for an
abnormal amount of coolant or steam. This would be
emitting from exhaust pipe. Coolant or steam from
exhaust pipe may indicate a faulty cylinder head gas-
ket, cracked engine cylinder block or cylinder head.
A convenient check for exhaust gas leakage into
cooling system is provided by a commercially avail-able Block Leak Check tool. Follow manufacturers
instructions when using this product.
COMBUSTION LEAKAGE TEST - WITHOUT
PRESSURE TESTER
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE CYLINDER BLOCK
DRAIN PLUGS OR LOOSEN RADIATOR DRAIN-
COCK WITH SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
Drain sufficient coolant to allow thermostat
removal. (Refer to 7 - COOLING/ENGINE/ENGINE
COOLANT THERMOSTAT - REMOVAL). Remove
accessory drive belt (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - REMOVAL).
Add coolant to radiator to bring level to within 6.3
mm (1/4 in) of top of thermostat housing.
CAUTION: Avoid overheating. Do not operate
engine for an excessive period of time. Open drain-
cock immediately after test to eliminate boil over.
Start engine and accelerate rapidly three times, to
approximately 3000 rpm while observing coolant. If
internal engine combustion gases are leaking into
cooling system, bubbles will appear in coolant. If bub-
bles do not appear, internal combustion gas leakage
is not present.
7s - 4 COOLING - 2.4LKJ
COOLING - 2.4L (Continued)

TRANSMISSION
TABLE OF CONTENTS
page page
TRANS COOLER
DESCRIPTION.........................30STANDARD PROCEDURE - FLUSHING
COOLERS AND TUBES.................30
TRANS COOLER
DESCRIPTION
An internal high capacity/high efficiency cooler is
used on all vehicles, these coolers are an oil-to-cool-
ant type, which consists of plates mounted in the
radiator outlet tank.Because the internal oil cooler is
so efficient, no auxiliary oil cooler is offered. The
cooler is not serviceable separately from the radiator.
STANDARD PROCEDURE - FLUSHING
COOLERS AND TUBES
When a transmission failure has contaminated the
fluid, the oil cooler(s) must be flushed. The torque
converter must also be replaced. This will insure that
metal particles or sludged oil are not later trans-
ferred back into the reconditioned (or replaced) trans-
mission.
The only recommended procedure for flushing cool-
ers and lines is to use Tool 6906-B Cooler Flusher.
WARNING: WEAR PROTECTIVE EYEWEAR THAT
MEETS THE REQUIREMENTS OF OSHA AND ANSI
Z87.1±1968. WEAR STANDARD INDUSTRIAL RUB-
BER GLOVES. KEEP LIGHTED CIGARETTES,
SPARKS, FLAMES, AND OTHER IGNITION
SOURCES AWAY FROM THE AREA TO PREVENT
THE IGNITION OF COMBUSTIBLE LIQUIDS AND
GASES. KEEP A CLASS (B) FIRE EXTINGUISHER IN
THE AREA WHERE THE FLUSHER WILL BE USED.
KEEP THE AREA WELL VENTILATED.DO NOT LET
FLUSHING SOLVENT COME IN CONTACT WITH
YOUR EYES OR SKIN: IF EYE CONTAMINATION
OCCURS, FLUSH EYES WITH WATER FOR 15 TO 20
SECONDS. REMOVE CONTAMINATED CLOTHING
AND WASH AFFECTED SKIN WITH SOAP AND
WATER. SEEK MEDICAL ATTENTION.
(1) Remove cover plate filler plug on Tool 6906-B.
Fill reservoir 1/2 to 3/4 full of fresh flushing solution.
Flushing solvents are petroleum based solutions gen-
erally used to clean automatic transmission compo-
nents.DO NOTuse solvents containing acids, water,
gasoline, or any other corrosive liquids.(2) Reinstall filler plug on Tool 6906-B.
(3) Verify pump power switch is turned OFF. Con-
nect red alligator clip to positive (+) battery post.
Connect black (-) alligator clip to a good ground.
(4) Disconnect the cooler lines at the transmission.
NOTE: When flushing transmission cooler and
lines, ALWAYS reverse flush.
NOTE: The converter drainback valve must be
removed and an appropriate replacement hose
installed to bridge the space between the transmis-
sion cooler line and the cooler fitting. Failure to
remove the drainback valve will prevent reverse
flushing the system. A suitable replacement hose
can be found in the adapter kit supplied with the
flushing tool.
(5) Connect the BLUE pressure line to the OUT-
LET (From) cooler line.
(6) Connect the CLEAR return line to the INLET
(To) cooler line
(7) Turn pump ON for two to three minutes to
flush cooler(s) and lines.
(8) Turn pump OFF.
(9) Disconnect CLEAR suction line from reservoir
at cover plate. Disconnect CLEAR return line at
cover plate, and place it in a drain pan.
(10) Turn pump ON for 30 seconds to purge flush-
ing solution from cooler and lines. Turn pump OFF.
(11) Place CLEAR suction line into a one quart
container of MopartATF +4, type 9602, Automatic
Transmission Fluid.
(12) Turn pump ON until all transmission fluid is
removed from the one quart container and lines. This
purges any residual cleaning solvent from the trans-
mission cooler and lines. Turn pump OFF.
(13) Disconnect alligator clips from battery. Recon-
nect flusher lines to cover plate, and remove flushing
adapters from cooler lines.
7s - 30 TRANSMISSIONKJ

ness routing and retention, connector pin-out infor-
mation and location views for the various wire
harness connectors, splices and grounds.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel center trim
panel.
(3) Remove the radio mounting screws (Fig. 7).
(4) Disconnect the antenna cable by pulling the
locking antenna connector away from the radio (Fig.
8).
(5) Disconnect the electrical harness connector(s).
(6) Remove radio from instrument panel.
INSTALLATION
(1) Connect the wire harness connector(s).
(2) Connect the antenna cable.
(3) Install the radio to the instrument panel.
(4) Install the radio mounting screws.
(5) Install the instrument panel center trim panel.
(6) Connect the battery negative cable.
RADIO NOISE SUPPRESSION
GROUND STRAP
DESCRIPTION
Radio noise suppression devices are factory-in-
stalled standard equipment on this vehicle. Radio
Frequency Interference (RFI) and ElectroMagnetic
Interference (EMI) can be produced by any on-board
or external source of electromagnetic energy. These
electromagnetic energy sources can radiate electro-
magnetic signals through the air, or conduct them
through the vehicle electrical system.
When the audio system converts RFI or EMI to an
audible acoustic wave form, it is referred to as radio
noise. This undesirable radio noise is generally man-
ifested in the form of ªbuzzing,º ªhissing,º ªpopping,º
ªclicking,º ªcrackling,º and/or ªwhirringº sounds. In
most cases, RFI and EMI radio noise can be sup-
pressed using a combination of vehicle and compo-
nent grounding, filtering and shielding techniques.
This vehicle is equipped with factory-installed radio
noise suppression devices that were designed to min-
imize exposure to typical sources of RFI and EMI;
thereby, minimizing radio noise complaints.
Factory-installed radio noise suppression is accom-
plished primarily through circuitry or devices that
are integral to the factory-installed radios, audio
power amplifiers and other on-board electrical com-
ponents such as generators, wiper motors, blower
motors, and fuel pumps that have been found to be
potential sources of RFI or EMI. External radio noise
suppression devices that are used on this vehicle to
control RFI or EMI, and can be serviced, include the
following:
²Engine-to-body ground strap- This length of
braided ground strap has an eyelet terminal connec-
tor crimped to each end. One end is secured to the
engine cylinder head(s). The other is secured to the
plenum.
²Resistor-type spark plugs- This type of spark
plug has an internal resistor connected in series
between the spark plug terminal and the center elec-
trode to help reduce the production of electromag-
netic radiation that can result in radio noise.
Fig. 7 RADIO
Fig. 8 ANTENNA TO RADIO
1 - RADIO
2 - LOCKING ANTENNA CONNECTOR
3 - INSTRUMENT PANEL ANTENNA CABLE
KJAUDIO 8A - 9
RADIO (Continued)

IGNITION CONTROL
TABLE OF CONTENTS
page page
IGNITION CONTROL
DESCRIPTION..........................1
OPERATION............................1
SPECIFICATIONS
SPECIFICATIONS - IGNITION TIMING.......2
ENGINE FIRING ORDER - 2.4L 4-CYLINDER . 2
ENGINE FIRING ORDER - 3.7L V-6.........2
IGNITION COIL RESISTANCE - 2.4L........2
IGNITION COIL RESISTANCE - 3.7L V-6.....3
SPARK PLUGS........................3
SPARK PLUG CABLE RESISTANCE - 2.4L . . . 3
TORQUE - IGNITION SYSTEM............3
AUTO SHUT DOWN RELAY
DESCRIPTION - PCM OUTPUT.............4
OPERATION
OPERATION - ASD SENSE - PCM INPUT....4
OPERATION - PCM OUTPUT.............4
DIAGNOSIS AND TESTING - ASD AND FUEL
PUMP RELAYS........................4
REMOVAL.............................5
INSTALLATION..........................5
CAMSHAFT POSITION SENSOR
DESCRIPTION
DESCRIPTION - 2.4L....................5
DESCRIPTION-3.7L.....................6
OPERATION
OPERATION - 2.4L.....................6OPERATION - 3.7L.....................6
REMOVAL.............................7
INSTALLATION..........................8
IGNITION COIL
DESCRIPTION..........................9
OPERATION............................9
REMOVAL.............................10
INSTALLATION.........................10
KNOCK SENSOR
DESCRIPTION.........................11
OPERATION...........................11
REMOVAL.............................12
INSTALLATION.........................12
SPARK PLUG
DESCRIPTION.........................12
OPERATION...........................12
DIAGNOSIS AND TESTING - SPARK PLUG
CONDITIONS.........................13
REMOVAL.............................15
CLEANING SPARK PLUGS................15
INSTALLATION.........................15
IGNITION COIL CAPACITOR
DESCRIPTION.........................16
OPERATION...........................16
REMOVAL.............................16
INSTALLATION.........................16
IGNITION CONTROL
DESCRIPTION
The ignition system consists of:
²Spark Plugs
²Ignition Coil(s)
²Powertrain Control Module (PCM)
²Crankshaft Position Sensor
²2 Knock Sensors (3.7L only)
²Camshaft Position Sensor
²The MAP, TPS, IAC and ECT also have an effect
on the control of the ignition system.
OPERATION
2.4L
A common ignition coil divided into 2 halves is
used. Secondary, high-tension spark plug cables are
also used. One half of the coil fires two spark plugs
simultaneously (one plug is the cylinder under com-pression, and the other plug is the cylinder on the
exhaust stroke). Coil half number one fires cylinders
1 and 4. Coil half number two fires cylinders 2 and 3.
The PCM determines which of the coils to charge and
fire at the correct time.
The Auto Shutdown (ASD) relay provides battery
voltage to the ignition coil. The PCM provides a
ground contact (circuit) for energizing the coil. When
the PCM breaks the contact, the energy in the coil
primary transfers to the secondary causing a spark.
The PCM will de-energize the ASD relay if it does
not receive inputs from either the crankshaft or cam-
shaft position sensors.
A distributor is not used with the 2.4L engine.
3.7L
The 3.7L V6 engine uses a separate ignition coil for
each cylinder. The one-piece coil bolts directly to the
cylinder head. Rubber boots seal the secondary ter-
minal ends of the coils to the top of all 6 spark plugs.
A separate electrical connector is used for each coil.
KJIGNITION CONTROL 8I - 1

Because of coil design, spark plug cables (second-
ary cables) are not used. A distributor is not used
with the 3.7L engine.
Two knock sensors (one for each cylinder bank) are
used to help control spark knock.
The Auto Shutdown (ASD) relay provides battery
voltage to each ignition coil. The Powertrain Control
Module (PCM) provides a ground contact (circuit) for
energizing each coil. When the PCM breaks the con-
tact, the energy in the coil primary transfers to the
secondary causing a spark. The PCM will de-energize
the ASD relay if it does not receive inputs from
either the crankshaft or camshaft position sensors.
SPECIFICATIONS
SPECIFICATIONS - IGNITION TIMING
Ignition timing is not adjustable on any
engine.
ENGINE FIRING ORDER - 2.4L 4-CYLINDER1-3-4-2
ENGINE FIRING ORDER - 3.7L V-61-6-5-4-3-2
IGNITION COIL RESISTANCE - 2.4L
Engine Coil ManufacturePrimary Resistance at
21ÉC-27ÉC (70ÉF-80ÉF)Secondary Resistance at
21ÉC-27ÉC (70ÉF-80ÉF)
2.4L Toyodenso or Diamond 0.51 to 0.61 Ohms 11,500 to 13,500 Ohms
Fig. 1 IGNITION COIL - 2.4L
8I - 2 IGNITION CONTROLKJ
IGNITION CONTROL (Continued)

IGNITION COIL RESISTANCE - 3.7L V-6
PRIMARY RESISTANCE
21-27ÉC (70-80ÉF)SECONDARY
RESISTANCE 21-27ÉC
(70-80ÉF)
0.6 - 0.9 Ohms 6,000 - 9,000 Ohms
SPARK PLUGS
ENGINE PLUG TYPE ELECTRODE GAP
2.4L RE14MCC5 (Champion #) 1.24 to 1.37 mm (0.048 to 0.053 in.)
3.7L V-6 2FR6F - 11G (NGK #) 1.1 mm (0.042 in.)
SPARK PLUG CABLE RESISTANCE - 2.4L
MINIMUM MAXIMUM
250 Ohms Per Inch 1000 Ohms Per Inch
3000 Ohms Per Foot 12,000 Ohms Per Foot
TORQUE - IGNITION SYSTEM
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Camshaft Position Sensor-2.4L 23 21 205
Camshaft Position Sensor±3.7L 12 - 106
Crankshaft Position Sensor Bolt-2.4L 12 - 106
Crankshaft Position Sensor Nut/Bolt-3.7L 23 21 205
* Knock Sensor Bolt - 3.7L * 20 * 15
Ignition Coil Mounting Bolts - 2.4L 11 - 105
Ignition Coil Mounting Nuts - 3.7L 8 - 70
Ignition Coil Capacitor Nuts- 3.7L 8 - 70
** Spark Plugs - 2.4L ** 15 ** 11 -
Spark Plugs - 3.7L 27 20 -
* Do not apply any sealant, thread-locker or adhesive to
bolts. Poor sensor performance may result.
** Torque critical tapered design. Do not exceed 15 ft. lbs.
KJIGNITION CONTROL 8I - 3
IGNITION CONTROL (Continued)