JEEP WRANGLER 2008 JK / 3.G Owners Manual

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.
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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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CAUTION!
Overfilling or underfilling the crankcase will cause
aeration or loss of oil pressure. This could damage
your engine.
Change Engine Oil
Refer to the Maintenance Schedule in Section 8 for
recommended engine oil change intervals.
Engine Oil Selection
For best performance and maximum protection for all
engines under all types of operating conditions, the
manufacturer recommends engine oils that are API Cer-
tified and meet the requirements of DaimlerChrysler
Material Standard MS-6395.
American Petroleum Institute (API) Engine Oil
Identification Symbol
This symbol means that the oil has
been certified by the American
Petroleum Institute (API). The
manufacturer only recommends
API Certified engine oils.
Engine Oil Viscosity (3.8L Engines)
SAE 5W-20 engine oil is recommended for all operating
temperatures. This engine oil improves low temperature
starting and vehicle fuel economy.
The engine oil filler cap also shows the recommended
engine oil viscosity for your engine. For information on
engine oil filler cap location, refer to the “Engine Com-
partment” illustration in this section.
384 MAINTAINING YOUR VEHICLE

Lubricants which do not have both, the engine oil certi-
fication mark and the correct SAE viscosity grade num-
ber, should not be used.
Synthetic Engine Oils
Synthetic engine oils can be used if the recommended oil
quality requirements are met, and the recommended
maintenance intervals for oil and filter changes are
followed.
Materials Added To Engine Oils
The manufacturerstrongly recommends against the ad-
dition of any additives (other than leak detection dyes) to
engine oil. Engine oil is an engineered product and its
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. MOPAR
engine oil filters are high
quality oil filters and are recommended.
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Drive Belts — Check Condition and Tension
Belt tension is controlled by means of an automatic
tensioner. No belt tension adjustments are required.
However, belt and belt tensioner condition should be
inspected at the specified intervals, and replaced if re-
quired. See your authorized dealer for service
At the mileage indicated in the Maintenance Schedule,
the condition of all the belts and tensioner should be
checked. Refer to Section 8 of this manual. Improper belt
tension can cause belt slippage and failure.
Belts should be inspected for evidence of cuts, cracks,
glazing, or frayed cords and replaced if there is indication
of damage, which could result in belt failure. Low
generator belt tension can cause battery failure.
Also, check belt routing to make sure there is no inter-
ference 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 Maintenance Sched-
ule. Refer to Section 8 of this manual. The entire set
should be replaced if there is any malfunction due to a
faulty spark plug. Refer to Fluids, Lubricants, and Genu-
ine Parts in this section 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.
386 MAINTAINING YOUR VEHICLE

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.
WARNING!
A hot exhaust system can start a fire if you park over
materials that can burn. Such materials might be
grass or leaves coming into contact with your exhaust
system. Do not park or operate your vehicle in areas
where your exhaust system can contact anything that
can burn.
In unusual situations involving grossly malfunctioning
engine operation, a scorching odor may suggest severe
and abnormal catalyst overheating. If this occurs, stop
the vehicle, turn off the engine and allow it to cool.
Service, including a tune up to manufacturer’s specifica-
tions, should be obtained immediately.
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To minimize the possibility of catalytic converter dam-
age:
•Do not shut off the engine or interrupt the ignition
when the transmission is in gear and the vehicle is in
motion.
•Do not try to start the engine by pushing or towing the
vehicle.
•Do not idle the engine with any spark plug wires
disconnected or removed, such as when diagnostic
testing.
•Do not idle the engine for prolonged periods during
very rough idle or malfunctioning operating condi-
tions.
•Do not allow vehicle to run out of fuel.NOTE:
Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
Crankcase Emission Control System
Proper operation of this system depends on freedom
from sticking or plugging due to deposits. As vehicle
mileage builds up, the PCV valve and passages may
accumulate deposits. If a valve is not working properly,
replace it with a new valve. DO NOT ATTEMPT TO
CLEAN THE OLD PCV VALVE!
Check ventilation hose for indication of damage or
plugging deposits. Replace if necessary.
Fuel Filter
A plugged fuel filter can cause hard starting or limit the
speed at which a vehicle can be driven. Should an
excessive amount of dirt accumulate in the fuel tank,
frequent replacement of the fuel filter which is mounted
in the fuel tank may be necessary.
388 MAINTAINING YOUR VEHICLE

Engine Air Cleaner Filter
Refer to the Maintenance Schedule in Section 8 for
recommended engine air cleaner filter change intervals.
WARNING!
The air cleaner can provide protection in the case of
engine backfire. Do not remove the air cleaner unless
it is necessary for repair or maintenance. Make sure
that no one is near the engine compartment before
starting the vehicle with the air cleaner removed.
Failure to do so can result in serious personal injury.
Maintenance-Free Battery
Your vehicle is equipped with a maintenance-free battery.
You will never have to add water, nor is periodic main-
tenance required.
WARNING!
Battery posts, terminals, and related accessories con-
tain lead and lead compounds. Always wash hands
after handling the battery.
CAUTION!
It is essential when replacing the cables on the
battery that the positive cable is attached to the
positive post and the negative cable is attached to the
negative post. Battery posts are marked (+) positive
and negative (-) and identified on the battery case.
Also, if a “fast charger” is used while battery is in the
vehicle, disconnect both vehicle battery cables before
connecting the charger to battery. Do not use a “fast
charger” to provide starting voltage.
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