2004 JEEP WRANGLER maintenance

WARNING!
A fire may result if gasoline is pumped into a
portable container that is inside of a vehicle. You
could be burned. Always place gas containers on the
ground while filling.
Locking Fuel Filler Cap (Gas Cap) Ð If Equipped
²
Turn the engine off.
²Insert the ignition key into the fuel cap, and turn the
key to the right to unlock the fuel cap. Rotate the fuel
cap to the left to remove.
²To replace the cap, insert it into the filler neck and
tighten the cap about 1/4 turn until you hear one click.
This is an indication that the cap is properly tightened.
²Make sure that the fuel cap tether strap is not caught
under the fuel cap.
²Be sure to remove the key.
CAUTION!
To avoid fuel spillage and overfilling, do not ªtop
offº the fuel tank after filling.
NOTE:When the fuel nozzle ªclicksº or shuts off, the
fuel tank is full.
TRAILER TOWING
In this section you will find information on limits to the
type of towing you can reasonably do with your vehicle.
Before towing a trailer, carefully review this information
to tow your load as efficiently and safely as possible.
To maintain warranty coverage, follow the requirements
and recommendations in this manual concerning ve-
hicles used for trailer towing.
Perform maintenance services as prescribed in the
ªMaintenance Schedulesº section. When your vehicle is
used for trailer towing, never exceed the gross axle
weight rating (GAWR) by the addition of:
²The tongue weight of the trailer.
202 STARTING AND OPERATING

²The weight of any other type of cargo or equipment
put in or on your vehicle.
Remember that everything put in or on the trailer adds to
the load on your vehicle.
Warranty Requirements
The manufacturer's warranty will apply to vehicles used
to tow trailers for noncommercial use, however the
following conditions must be met:
²The ªDº Overdrive range can be selected when tow-
ing. However, if frequent shifting occurs move the
shift lever to the next lower position to eliminate
excessive automatic transmission shifting. This action
will also reduce the possibility of transmission over-
heating and provide better engine braking. Refer to
ªTransmission Shiftingº in this section for additional
information.
²A load equalizing hitch is recommended for loaded
trailer weights above 1,000 lbs (454 kg).
CAUTION!
If the trailer weighs more than 1,000 lbs (454 kg)
loaded, it should have its own brakes and they
should be of adequate capacity. Failure to do this
could lead to accelerated brake lining wear, higher
brake pedal effort, and longer stopping distances.
WARNING!
Connecting trailer brakes to your vehicle's hydraulic
brake lines can overload your brake system and
cause it to fail. You might not have brakes when you
need them and could have an accident.
²Whenever you pull a trailer, regardless of the trailer
size, stop lights and turn signals on the trailer are
mandatory for motoring safety.
²Follow the maintenance intervals in schedule ªBº for
changing the automatic transmission fluid and filter, if
you REGULARLY tow a trailer for more than 45
minutes of continuous operation.
STARTING AND OPERATING 203
5

MAINTAINING YOUR VEHICLE
CONTENTS
m2.4L Engine..........................223
m4.0L Engine..........................224
mOnboard Diagnostic System Ð OBD II......225
mEmissions Inspection And
Maintenance Programs
..................226
mReplacement Parts.....................227
mDealer Service........................227
mMaintenance Procedures.................228
NEngine Oil..........................228
NDrive Belts Ð Check Condition And Tension . . 231
NSpark Plugs.........................232
NCatalytic Converter....................232NEngine Timing Belt Ð 2.4L Engine.........233
NIgnition Wiring System Ð 2.4L Engine......233
NCrankcase Emission Control System........234
NFuel Filter..........................234
NEngine Air Cleaner Filter................234
NMaintenance-Free Battery................234
NAir Conditioner Maintenance.............235
NPower Steering Fluid Check..............236
NDriveline And Steering Component
Lubrication..........................237
NBody Lubrication.....................237
NWindshield Wiper Blades................237
7

EMISSIONS INSPECTION AND MAINTENANCE
PROGRAMS
In some localities, it may be a legal requirement to pass
an inspection of your vehicle's emissions control system.
Failure to pass could prevent vehicle registration.
For states which have an I/M (Inspection and
Maintenance) requirement, this check verifies the
following: the MIL (Malfunction Indicator Lamp)
is functioning and is not on when the engine is running,
and that the OBD (On Board Diagnostic) system is ready
for testing.
Normally, the OBD system will be ready. The OBD
system maynotbe ready if your vehicle was recently
serviced, if you recently had a dead battery, or a battery
replacement. If the OBD system should be determined
not ready for the I/M test, your vehicle may fail the test.
Your vehicle has a simple ignition key actuated test
which you can use prior to going to the test station. To
check if your vehicle's OBD system is ready, you must do
the following:
1. Insert your ignition key into the ignition switch.2. Turn the ignition to the ON position, but do not crank
or start the engine.
3. If you crank or start the engine, you will have to start
this test over.
4. As soon as you turn your key to the ON position, you
will see your MIL symbol come on as part of a normal
bulb check.
5. Approximately 15 seconds later, one of two things will
happen:
a. The MIL will flash for about 10 seconds and then
return to being fully illuminated until you turn off
the ignition key or start the engine. This means that
your vehicle's OBD system isnot readyand you
shouldnotproceed to the I/M station.
b. The MIL will not flash at all and will remain fully
illuminated until you turn off the ignition key or
start the engine. This means that your vehicle's OBD
system isreadyand you can proceed to the I/M
station.
226 MAINTAINING YOUR VEHICLE

If your OBD system isnot ready,you should see your
authorized dealer or repair facility. If your vehicle was
recently serviced or had a battery failure or replacement,
you may need to do nothing more than drive your
vehicle as you normally would in order for your OBD
system to update. A recheck with the above test routine
may then indicate that the system is now ready.
Regardless of whether your vehicle's OBD system is
ready or not ready, if the MIL symbol is illuminated
during normal vehicle operation, you should have your
vehicle serviced before going to the I/M station. The I/M
station can fail your vehicle because the MIL symbol is on
with the engine running.REPLACEMENT PARTS
Use of genuine Mopartparts for normal/scheduled
maintenance and repairs is highly recommended to in-
sure the designed performance. Damage or failures
caused by the use of non-Mopartparts for maintenance
and repairs will not be covered by the manufacturer's
warranty.
DEALER SERVICE
Your dealer has the qualified service personnel, special
tools and equipment to perform all service operations in
an expert manner. Service Manuals are available which
include detailed service information for your vehicle.
Refer to these manuals before attempting any procedure
yourself.
NOTE:Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
MAINTAINING YOUR VEHICLE 227
7

WARNING!
You can be badly injured working on or around a
motor vehicle. Do only that service work for which
you have the knowledge and the proper equipment.
If you have any doubt about your ability to perform
a service job, take your vehicle to a competent
mechanic.
MAINTENANCE PROCEDURES
The pages that follow contain therequiredmaintenance
services determined by the engineers who designed your
vehicle.
Besides the maintenance items for which there are fixed
maintenance intervals, there are other items that should
operate satisfactorily without periodic maintenance.
However, if a malfunction of these items does occur, it
could adversely affect the engine or vehicle performance.
These items should be inspected if a malfunction is
observed or suspected.
Engine Oil
Checking Oil Level
To assure proper lubrication of your vehicle's engine, the
engine oil must be maintained at the correct level. Check
the oil level at regular intervals, such as every fuel stop.
The best time to check the engine oil level is about 5
minutes after a fully warmed engine is shut off, or before
starting the engine after it has sat overnight.
Checking the oil while the vehicle is on level ground will
improve the accuracy of the oil level readings. Maintain
the oil level between the ADD and SAFE markings on the
dipstick. Adding 1 U.S. Quart (0.95L) of oil when the
reading is at the ADD mark will result in a SAFE reading
on these engines.
228 MAINTAINING YOUR VEHICLE

Materials Added To Engine Oils
The manufacturerstrongly recommendsagainst the ad-
dition of any additives (other than leak detection dyes) to
engine oil. Engine oil is an engineered product and it's
performance may be impaired by supplemental addi-
tives.
Disposing of Used Engine Oil
Care should be taken in disposing of used engine oil from
your vehicle. Used oil, indiscriminately discarded, can
present a problem to the environment. Contact your
authorized dealer, service station, or governmental
agency for advice on how and where used oil can be
safely discarded in your area.
Engine Oil Filter
The engine oil filter should be replaced at every engine
oil change.
Engine Oil Filter Selection
All of the manufacturer's engines have a full-flow type
disposable oil filter. Use a filter of this type for replace-
ment. The quality of replacement filters varies consider-
ably. Only high quality filters should be used to assure
most efficient service. Mopartengine oil filters are high
quality oil filters and are recommended.
Drive Belts Ð Check Condition and Tension
At the mileage shown in the appropriate ªMaintenance
Schedule,º check all drive belts for condition and proper
tension. Improper belt tension can cause belt slippage
and failure.
4.0L Engines
MAINTAINING YOUR VEHICLE 231
7

Inspect the drive belt for evidence of cuts, cracks, or
glazing and replace them if there is any sign of damage
which could result in belt failure. If adjustment is re-
quired, adjust the belts according to the specifications
and procedures shown in the Service Manual.
Special tools are required to properly measure tension
and to restore belt tension to factory specifications. Also,
check belt routing to make sure there is no interference
between the belts and other engine components.
Spark Plugs
Spark plugs must fire properly to assure engine perfor-
mance and emission control. New plugs should be in-
stalled at the mileage specified in the appropriate main-
tenance chart. The entire set should be replaced if there is
any malfunction due to a faulty spark plug.
Refer to the ªVehicle Emission Control Informationº label
in the engine compartment for spark plug information.
Catalytic Converter
The catalytic converter requires the use of unleaded fuel
only. Leaded gasoline will destroy the effectiveness of the
converter as an emission control device.
Under normal operating conditions, the catalytic con-
verter will not require maintenance. However, it is im-
portant to keep the engine properly tuned to assure
proper catalyst operation and prevent possible catalyst
damage.
CAUTION!
Damage to the catalytic converter can result if your
vehicle is not kept in proper operating condition. In
the event of engine malfunction, particularly involv-
ing engine misfire or other apparent loss of perfor-
mance, have your vehicle serviced promptly. Contin-
ued operation of your vehicle with a severe
malfunction could cause the converter to overheat,
resulting in possible damage to the converter and
vehicle.
232 MAINTAINING YOUR VEHICLE