fuel JEEP WRANGLER 2008 User Guide

If using a manual transmission vehicle for trailer towing,
all starts must be in 1st gear to avoid excessive clutch
slippage.
Towing Tips — Automatic Transmission
The DRIVE range can be selected when towing. How-
ever, if frequent shifting occurs while in this range, the
OVERDRIVE range should be selected.
NOTE:Using “O/D OFF” while operating the vehicle
under heavy operating conditions will improve perfor-
mance and extend transmission life by reducing exces-
sive shifting and heat build up. This action will also
provide better engine braking.
The automatic transmission fluid and filter should be
changed if you REGULARLY tow a trailer for more than
45 minutes of continuous operation. Refer to the “Main-
tenance Schedule” in Section 8 of this manual for trans-
mission fluid change intervals. NOTE:
Check the automatic transmission fluid level
before towing.
Towing Tips — O/D Off
To reduce potential for automatic transmission overheat-
ing, select the “O/D OFF” feature when driving in hilly
areas or shift the transmission to DRIVE position 2 on
more severe grades. Refer to “Transmission Shifting” in
this section.
Towing Tips — Electronic Speed Control (If
Equipped)

Don’t use in hilly terrain or with heavy loads.
When using the speed control, if you experience speed
drops greater than 10 mph (16 km/h), disengage until
you can get back to cruising speed.
Use speed control in flat terrain and with light loads to
maximize fuel efficiency.
358 STARTING AND OPERATING

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.

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.

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

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

Following off-road usage, completely inspect the under-
body of your vehicle. Check tires, body structure, steer-
ing, suspension and exhaust system for damage. Check
threaded fasteners for looseness, particularly on the
chassis, drivetrain components, steering and suspension.
Retighten, if required, to torque values specified in the
Service Manual. Also check for accumulations of vegeta-
tion or brush that could become a fire hazard, or conceal
damage to fuel lines, brake hoses, axle pinion seals, and
propeller shafts. Check air conditioning drain tube on the
lower dash wall in the engine compartment for mud or
debris, and clean as required. A plugged tube will
adversely affect air conditioning performance.

Cavity CartridgeFuseMini
Fuse Description
J4 25 Amp Natural Driver Door Node
J5 25 Amp Natural Passenger Door Node
J6 40 Amp Green Anti-Lock Brake System
(ABS) Pump Feed/ESP
J7 30 Amp Pink Anti-Lock Brake System
(ABS) Valve Feed/ESP
J8 — —
J9 40 Amp Green PZEV Sec Motor Feed/
Flex Fuel
J10 30 Amp Pink Headlamp Wash Relay/
Manifold Tuning Valve
J11 30 Amp Pink Sway Bar

ABS (Anti-Lock Brake System)............208,309
Adding Fuel ........................... 340
Adding Washer Fluid ..................... 198
Air Cleaner, Engine (Engine Air Cleaner Filter) . . . 389
Air Conditioner Maintenance ............... 390
Air Conditioning ..................... 261,264
Air Conditioning Controls ................. 264
Air Conditioning, Operating Tips ............ 265
Air Conditioning Refrigerant ............... 391
Air Conditioning System .................. 264
Air Filter .............................. 389
Air Pressure, Tires ....................... 322
Airbag ................................ 51
Airbag Deployment ....................... 57
Airbag Light ......................... 60,208
Airbag Maintenance ....................... 59
Airbag, Side ............................ 57
Alarm (Security Alarm) .................... 18
Alignment and Balance ................... 328 Alterations/Modifications, Vehicle
............. 8
Antenna, Satellite Radio ................... 255
Antifreeze (Engine Coolant) ................ 424
Anti-Lock Brake System (ABS) ............105,309
Anti-Lock Warning Light .................. 208
Appearance Care ........................ 406
Arming Theft System (Security Alarm) ......... 18
Audio Systems (Radio) .................... 250
Auto Down Power Windows ................ 37
Automatic Transmission ................... 401
Fluid and Filter Changes ................. 401
Fluid Level Check ...................... 401
Fluid Type ........................... 401
Gear Ranges .......................... 281
Shifting ............................. 281
Special Additives ...................... 403
Torque Converter ...................... 285
Auxiliary Electrical Outlet (Power Outlet) ....... 116
Auxiliary Power Outlet .................... 116
446 INDEX

Jacking............................. 366
Jump Starting ......................... 371
Tow Hooks .......................... 374
Emission Control System Maintenance ......380,428
Engine ................................ 75
Air Cleaner .......................... 389
Block Heater ......................... 275
Break-In Recommendations ................ 75
Compartment ......................... 378
Compartment Identification ............... 378
Exhaust Gas Caution .................. 75,339
Fails to Start .......................... 273
Flooded, Starting ...................... 273
Fuel Requirements .................. 336,424
Jump Starting ......................... 371
Oil .............................. 383,424
Oil Disposal .......................... 385
Oil Filter ............................ 385
Oil Selection .......................... 424 Operation
............................ 75
Overheating .......................... 365
Starting ............................. 271
Temperature Gauge ..................... 209
Engine Oil Viscosity ...................... 384
Engine Oil Viscosity Chart ................. 384
Enhanced Accident Response Feature .......... 59
Entry System, Illuminated .................. 19
Event Data Recorder ...................... 60
Exhaust Gas Caution ................... 75,339
Exhaust System ......................... 393
Extender, Seat Belt ........................ 50
Exterior Finish Care ...................... 407
Fabric Care ......................... 409,411
Fabric Top ............................. 411
Filters Air Cleaner .......................... 389
Engine Fuel .......................... 388
450 INDEX

Gasoline/Oxygenate Blends................ 337
Gauges Coolant Temperature .................... 209
Fuel ................................ 206
Odometer ............................ 211
Speedometer ......................... 206
Tachometer .......................... 209
Gear Ranges ........................ 276,281
General Information .................... 17,335
Glass Cleaning .......................... 410
Gross Axle Weight Rating ...............342,345
Gross Vehicle Weight Rating .............342,345
GVWR ............................... 342
Hands-Free Phone (UConnect™) ........85,250,251
Hard Drive (HDD) ....................... 250
HardTop ............................. 125
Hard Top, Modular ...................... 125
Hard Top Removal ....................... 129 Hazard Warning Flasher
................... 364
Head Restraints .......................... 89
Head Rests ............................. 89
Headlights Bulb Replacement ...................... 420
Dimmer Switch ........................ 98
Replacing ............................ 420
Switch ............................... 97
Heater ............................... 259
Heater, Engine Block ..................... 275
High Beam Indicator ..................... 207
Hitches Trailer Towing ........................ 348
Holder, Cup ........................... 117
Hood Release ........................... 94
Hoses ............................. 399,400
Hydraulic Clutch Fluid .................... 403
Ignition ............................... 12
452 INDEX