JEEP WRANGLER 2007 JK / 3.G Owners Manual

MAINTAINING YOUR VEHICLE
CONTENTS
Engine Compartment – 3.8L...............364
Onboard Diagnostic System — OBD II........365
▫Loose Fuel Filler Cap Message............366
Emissions Inspection And Maintenance
Programs............................366
Replacement Parts......................368
Dealer Service.........................368
Maintenance Procedures..................369
▫Engine Oil..........................369▫Drive Belts — Check Condition And Tension . . 372
▫Spark Plugs.........................373
▫Catalytic Converter....................373
▫Crankcase Emission Control System........375
▫Fuel Filter..........................375
▫Engine Air Cleaner Filter................375
▫Maintenance-Free Battery................376
▫Air Conditioner Maintenance.............376
▫Power Steering Fluid Check..............377
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▫Driveline And Steering Component
Lubrication..........................378
▫Body Lubrication.....................378
▫Windshield Wiper Blades................379
▫Windshield Washers...................379
▫Exhaust System......................380
▫Cooling System.......................380
▫Hoses And Vacuum/Vapor Harnesses.......385
▫Brake System........................386
▫Automatic Transmission................388
▫Hydraulic Clutch Fluid — Manual
Transmission........................390
▫Manual Transmission..................390
▫Transfer Case........................391▫Front/Rear Axle Fluid..................392
▫Appearance Care And Protection From
Corrosion...........................393
Fuses (Totally Integrated Power Module)......400
Vehicle Storage........................407
Replacement Bulbs — If Equipped...........408
Bulb Replacement......................409
▫Head Light..........................409
▫Front Park/Turn Signal.................410
▫Front Side Marker.....................410
▫Front Fog Light......................410
▫Rear Tail, Stop, Turn Signal, And Back-Up
Lights.............................411
▫Center High Mounted Stop Light (CHMSL) . . . 411
362 MAINTAINING YOUR VEHICLE

Fluid Capacities........................412
Fluids, Lubricants And Genuine Parts........413▫Engine.............................413
▫Chassis............................414
MAINTAINING YOUR VEHICLE 363
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ENGINE COMPARTMENT – 3.8L
364 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 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 driveability. 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.
MAINTAINING YOUR VEHICLE 365
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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 loose fuel filler cap message
will be displayed in the instrument cluster. Tighten the
gas cap until aclickingsound 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 problem is detected twice in a row, the system will
turn on the Malfunction Indicator Light (MIL). Resolving
the problem will turn the MIL 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, which have an I/M (Inspection and
Maintenance) requirement, this check verifies the
following: the MIL (Malfunction Indicator Light)
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.
366 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 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 theignition key or start the engine. This means that your
vehicle’s OBD system isnot readyand you shouldnot
proceed 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.
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
MAINTAINING YOUR VEHICLE 367
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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 Moparparts for normal/scheduled
maintenance and repairs is highly recommended to in-
sure the designed performance. Damage or failures
caused by the use of non-Moparparts 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.
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.
368 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 5 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 one quart 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.
MAINTAINING YOUR VEHICLE 369
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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
Road conditions as well as your kind of driving affect the
interval at which your oil should be changed. Check the
following to determine if any apply to you:
•Day or night temperatures are below 32°F (0°C)
•Stop and go driving
•Extensive engine idling
•Driving in dusty conditions
•Short trip driving of less than 10 miles (16.2 km)
•More than 50% of your driving is at sustained high
speeds during hot weather, above 90°F (32°C)
•Taxi, Police, or delivery service (commercial service)
•Trailer towing
•Off-road or desert driving
•If equipped for and operating with E–85 (ethanol) fuel
IfANYof these apply to you, then change your engine oil
at every interval shown in schedule “B” of the “Mainte-
nance Schedules” section of this manual.
If none of these apply to you, then change your engine oil
at every interval shown on schedule “A” of the “Main-
tenance Schedules” section of this manual
NOTE:Under no circumstances should oil change in-
tervals exceed 6,000 miles (10 000 km) or 6 months
whichever comes first.
370 MAINTAINING YOUR VEHICLE