2008 JEEP WRANGLER Owners Manual

▫Driveline And Steering Component
Lubrication ..........................392
▫ Body Lubrication .....................392
▫ Windshield Wiper Blades ................392
▫ Windshield And Rear Window Washers .....393
▫ Exhaust System ......................393
▫ Cooling System .......................394
▫ Hoses And Vacuum/Vapor Harnesses .......399
▫ Brake System ........................399
▫ Automatic Transmission ................401
▫ Hydraulic Clutch Fluid — Manual
Transmission ........................403
▫ Manual Transmission ..................403
▫ Transfer Case ........................404 ▫
Front/Rear Axle Fluid ..................405
▫ Maintenance After Off-Road Driving ........405
▫ Appearance Care And Protection From
Corrosion ...........................406
 Fuses (Totally Integrated Power Module) ......413
 Vehicle Storage ........................419
 Replacement Bulbs — If Equipped ...........420
 Bulb Replacement ......................420
▫ Head Light ..........................420
▫ Front Park/Turn Signal .................421
▫ Front Side Marker .....................422
▫ Front Fog Light ......................422
▫ Rear Tail, Stop, Turn Signal, And Backup
Lights .............................422
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▫Center High-Mounted Stop Light (CHMSL) . . . 423
 Fluid Capacities ........................424
 Fluids, Lubricants And Genuine Parts ........424▫
Engine .............................424
▫ Chassis ............................425
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ENGINE COMPARTMENT – 3.8L
378 MAINTAINING YOUR VEHICLE

ONBOARD DIAGNOSTIC SYSTEM — 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 “Malfunction Indicator Light.” 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 authorized dealer for service as
soon as possible.CAUTION!
•Prolonged driving with the “Malfunction Indica-
tor Light” on could cause further damage to the
emission control system. It could also affect fuel
economy and drivability. The vehicle must be
serviced before any emissions tests can be per-
formed.
•If the “Malfunction Indicator Light” is flashing
while the engine is running, severe catalytic con-
verter damage and power loss will soon occur.
Immediate service is required.
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Loose Fuel Filler Cap Message
After fuel is added, the vehicle diagnostic system can
determine if the fuel filler cap is possibly loose, improp-
erly installed, or damaged. A “gASCAP” message will be
displayed in the odometer. Tighten the gas cap until a
clickingsound is heard. This is an indication that the
gas cap is properly tightened. Press the odometer reset
button to turn the message off. If the problem persists,
the message will appear the next time the vehicle is
started. This might indicate a damaged cap. If the prob-
lem is detected twice in a row, the system will turn on the
“Malfunction Indicator Light.” Resolving the problem
will turn the “Malfunction Indicator Light.” off.
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 that require an Inspection and Mainte-
nance (I/M), this check verifies the Malfunction
Indicator Light (MIL) is functioning and is not on
when the engine is running, and that the OBD II system
is ready for testing.
Normally, the OBD II system will be ready. The OBD II
system may notbe ready if your vehicle was recently
serviced, recently had a dead battery, or a battery replace-
ment. If the OBD II system should be determined not
ready for the I/M test, your vehicle may fail the test.
380 MAINTAINING YOUR VEHICLE

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 II 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 the 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 II system is
not readyand you
should notproceed 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 II
system is ready, and you can proceed to the I/M
station.
If your OBD II system is not 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 II
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 II system is
ready or not ready, if the MIL is illuminated during
normal vehicle operation, you should have your vehicle
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serviced before going to the I/M station. The I/M station
can fail your vehicle because the MIL is on with the
engine running.
REPLACEMENT PARTS
Use of genuine MOPARparts for normal/scheduled
maintenance and repairs is highly recommended to en-
sure the designed performance. Damage or failures
caused by the use of non-MOPAR parts for maintenance
and repairs will not be covered by the manufacturer’s
warranty.
AUTHORIZED DEALER SERVICE
Your authorized dealer has the qualified service person-
nel, 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 Service manuals before
attempting any procedure yourself. NOTE:
Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
WARNING!
You can be badly injured working on or around a
motor vehicle. Only do 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.
382 MAINTAINING YOUR VEHICLE

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. The
best time to check the engine oil level is about five
minutes after a fully warmed up 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. Always
maintain the oil level within the SAFE zone on the
dipstick. Adding 1 U.S. Quart (0.95L) of oil when the
reading is at the bottom of the SAFE zone will result in a
reading at the top of the safe zone on these engines.
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