2008 JEEP WRANGLER fuel pressure

Airbag Warning Light
The light should come on and remain on for six to eight
seconds as a indicator check when the ignition switch is
first turned on. If the indicator is not lit during starting,
have it serviced. If the light stays on or comes on while
driving, have the system checked by an authorized
dealer.
Defrosters
Check operation by selecting the defrost mode and place
the blower control on high speed. You should be able to
feel the air directed against the windshield. See your
authorized dealer for service if your defroster is inoper-
able.
Safety Checks You Should Make Outside The
Vehicle
Tires
Examine tires for excessive tread wear or uneven wear
patterns. Check for stones, nails, glass, or other objects
lodged in the tread. Inspect for tread cuts or sidewall
cracks. Check wheel nuts for tightness and tires (includ-
ing spare) for proper pressure.
Lights
Have someone observe the operation of all exterior lights
while you work the controls. Check turn signal and high
beam indicator lights on the instrument panel.
Fluid Leaks
Check area under vehicle after overnight parking for fuel,
coolant, oil, or other fluid leaks. Also, if gasoline fumes
are detected, the cause should be located and corrected
immediately.
THINGS TO KNOW BEFORE STARTING YOUR VEHICLE 77
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INSTRUMENT CLUSTER DESCRIPTION
Your vehicle is equipped with the instrument cluster
described on the following pages.
1. Fuel Gauge
The pointer shows the level of fuel in the fuel tank.
NOTE:When the ignition switch is turned to OFF, the
fuel gauge, voltmeter, oil pressure and temperature
gauges may not show accurate readings. When the
engine is not running, turn the ignition switch to ON to
obtain accurate readings.
2. Charging System Warning Light This light shows the status of the electrical charg-
ing system. The light should come on for three
seconds when the ignition is first turned ON. If the light
comes back on immediately or comes on while driving, it
means that there is a problem with the charging system
or the battery is low. Also, a chime will sound if the light
comes back on. See your authorized dealer immediately. 3. Front Fog Light Indicator Light — If Equipped
This light shows when the front fog lights are on.
4. Low Fuel Warning Light When the fuel level reaches approximately 2.8 gal
(10.6L) this light will turn on and a single chime
will sound.
5. Speedometer
Indicates vehicle speed.
6. Front Axle Lock Indicator Light — If Equipped Indicates when the front axle lock has been
activated.
206 UNDERSTANDING YOUR INSTRUMENT PANEL

21. Odometer/Trip Odometer Reset Button
Press this button to change the display from odometer to
either of two trip odometer settings. Trip A or Trip B will
appear when in the trip odometer mode. Press and hold
the button for two seconds to reset the trip odometer to 0
miles or kilometers. The odometer must be in trip mode
to reset.
22. Transmission Range Indicator
This display indicator shows the automatic transmission
gear selection.
23. Tire Pressure Monitoring Telltale LightEach tire, including the spare (if provided),
should be checked monthly when cold and
inflated to the inflation pressure recommended
by the vehicle manufacturer on the vehicle
placard or tire inflation pressure label. (If your vehicle
has tires of a different size than the size indicated on the vehicle placard or tire inflation pressure label, you should
determine the proper tire inflation pressure for those
tires.)
As an added safety feature, your vehicle has been
equipped with a tire pressure monitoring system (TPMS)
that illuminates a low tire pressure telltale when one or
more of your tires is significantly under-inflated. Accord-
ingly, when the low tire pressure telltale illuminates, you
should stop and check your tires as soon as possible, and
inflate them to the proper pressure. Driving on a signifi-
cantly under-inflated tire causes the tire to overheat and
can lead to tire failure. Under-inflation also reduces fuel
efficiency and tire tread life, and may affect the vehicle’s
handling and stopping ability.
Please note that the TPMS is not a substitute for proper
tire maintenance, and it is the driver ’s responsibility to
maintain correct tire pressure, even if under-inflation has
not reached the level to trigger illumination of the TPMS
low tire pressure telltale.
210 UNDERSTANDING YOUR INSTRUMENT PANEL

▫Tire Identification Number (TIN) ..........316
▫ Tire Loading And Tire Pressure ...........317
 Tires — General Information ...............321
▫ Tire Pressure .........................321
▫ Tire Inflation Pressures .................322
▫ Tire Pressures For High-Speed Operation ....324
▫ Radial-Ply Tires ......................325
▫ Tire Spinning ........................325
▫ Tread Wear Indicators ..................326
▫ Life Of Tire .........................326
▫ Replacement Tires .....................327
▫ Alignment And Balance .................328
 Tire Chains ...........................329 
Tire Rotation Recommendations ............329
 Tire Pressure Monitor System (TPMS) ........330
▫ Base System .........................333
▫ General Information ...................335
 Fuel Requirements ......................336
▫ Reformulated Gasoline .................336
▫ Gasoline/Oxygenate Blends ..............337
▫ MMT In Gasoline .....................337
▫ Materials Added To Fuel ................338
▫ Fuel System Cautions ..................338
▫ Carbon Monoxide Warnings ..............339
 Adding Fuel ..........................340
▫ Fuel Filler Cap (Gas Cap) ...............340
STARTING AND OPERATING 269
5

Economy
Improper inflation pressures can cause uneven wear
patterns to develop across the tire tread. These abnormal
wear patterns will reduce tread life resulting in a need for
earlier tire replacement. Under-inflation also increases
tire rolling resistance and results in higher fuel consump-
tion.
Ride Comfort and Vehicle Stability
Proper tire inflation contributes to a comfortable ride.
Over-inflation produces a jarring and uncomfortable
ride.
Tire Inflation Pressures
Tire Placard Location (Two-Door Models)
322 STARTING AND OPERATING

CAUTION!
The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures have
been established for the tire size equipped on your
vehicle. Undesirable system operation or sensor
damage may result when using replacement equip-
ment that is not of the same size, type, and/or style.
Aftermarket wheels can cause sensor damage. Do not
use aftermarket tire sealants or balance beads if your
vehicle is equipped with a TPMS, as damage to the
sensors may result.
CAUTION!
After inspecting or adjusting the tire pressure always
reinstall the valve stem cap. This will prevent mois-
ture and dirt from entering the valve stem, which
could damage the Tire Pressure Monitoring Sensor.
NOTE:
•The TPMS is not intended to replace normal tire care
and maintenance, nor to provide warning of a tire
failure or condition.
•The TPMS should not be used as a tire pressure gauge
while adjusting your tire pressure.
•Driving on a significantly under-inflated tire causes
the tire to overheat and can lead to tire failure.
Under-inflation also reduces fuel efficiency and tire
tread life, and may affect the vehicle’s handling and
stopping ability.
332 STARTING AND OPERATING

Each axle’s GAWR is determined by the components in
the system with the lowest load carrying capacity (axle,
springs, tires, or wheels). Heavier axles or suspension
components, sometimes specified by purchasers for in-
creased durability, does not necessarily increase the ve-
hicle’s GVWR.
Tire Size
The tire size on the label represents the actual tire size on
your vehicle. Replacement tires must be equal to the load
capacity of this tire size.
Rim Size
This is the rim size that is appropriate for the tire size
listed.
Inflation Pressure
This is the cold tire inflation pressure for your vehicle for
all loading conditions up to full GAWR.
Curb Weight
The curb weight of a vehicle is defined as the total weight
of the vehicle with all fluids, including vehicle fuel, at full
capacity conditions, and with no occupants or cargo
loaded into the vehicle. The front and rear curb weight
values are determined by weighing your vehicle on a
commercial scale before any occupants or cargo are
added.
Loading
The actual total weight and the weight of the front and
rear of your vehicle at the ground can best be determined
by weighing it when it is loaded and ready for operation.
The entire vehicle should first be weighed on a commer-
cial scale to ensure that the GVWR has not been ex-
ceeded. The weight on the front and rear of the vehicle
should then be determined separately to be sure that the
load is properly distributed over front and rear axle.
Weighing the vehicle may show that the GAWR of either
STARTING AND OPERATING 343
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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