2004 JEEP WRANGLER engine

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
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NWindshield Washers...................238
NExhaust System......................238
NCooling System.......................239
NHoses And Vacuum/Vapor Harnesses.......242
NBrake System........................243
NAutomatic Transmission................245
NHydraulic Clutch Fluid Ð
Manual Transmission..................246
NManual Transmission..................246
NTransfer Case........................247
NFront/Rear Axle Fluid..................248
NAppearance Care And Protection
From Corrosion......................248mFuse Panel...........................254
NInterior Fuses........................254
NUnderhood Fuses
(Power Distribution Center)..............256
mVehicle Storage........................256
mReplacement Bulbs Ð If Equipped.........257
mFluid Capacities.......................258
mRecommended Fluids, Lubricants And
Genuine Parts
.........................259
NEngine.............................259
NChassis............................260
222 MAINTAINING YOUR VEHICLE

2.4L ENGINE
MAINTAINING YOUR VEHICLE 223
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4.0L ENGINE
224 MAINTAINING YOUR VEHICLE

ONBOARD DIAGNOSTIC SYSTEM Ð OBD II
Your vehicle is equipped with a sophisticated onboard
diagnostic system called OBD II. This system monitors
the performance of the emissions, engine, and automatic
transmission control systems. When these systems are
operating properly, your vehicle will provide excellent
performance and fuel economy, as well as engine emis-
sions well within current government regulations.
If any of these systems require service, the OBD II system
will turn on the ªMalfunction Indicator Light.º It will
also store diagnostic codes and other information to
assist your service technician in making repairs. Al-
though your vehicle will usually be drivable and not
need towing, see your dealer for service as soon as
possible.CAUTION!
²Prolonged driving with the ªMalfunction Indica-
tor Lightº on could cause further damage to the
emission control system. It could also affect fuel
economy and driveability. The vehicle must be
serviced before any emissions tests can be per-
formed.
²If the ªMalfunction Indicator Lightº is flashing
while the engine is running, severe catalytic con-
verter damage and power loss will soon occur.
Immediate service is required.
MAINTAINING YOUR VEHICLE 225
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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
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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