2012 JEEP GRAND CHEROKEE fuel pressure

Periodic Safety Checks You Should Make Outside
The Vehicle
Tires
Examine tires for excessive tread wear and uneven wear
patterns. Check for stones, nails, glass, or other objects
lodged in the tread or sidewall. Inspect the tread for cuts
and cracks. Inspect sidewalls for cuts, cracks and bulges.
Check the wheel nuts for tightness. Check the tires
(including spare) for proper cold inflation pressure.
Lights
Have someone observe the operation of exterior lights
while you work the controls. Check turn signal and high
beam indicator lights on the instrument panel.
Door Latches
Check for positive closing, latching, and locking.
Fluid Leaks
Check area under vehicle after overnight parking for fuel,
engine coolant, oil, or other fluid leaks. Also, if gasoline
fumes are detected or if fuel, power steering fluid, or
brake fluid leaks are suspected, the cause should be
located and corrected immediately.
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THINGS TO KNOW BEFORE STARTING YOUR VEHICLE 99

as it was before the repair or service. If s/he cannot do so,
then the odometer must be set at zero, and a sticker must
be placed in the door jamb stating what the mileage was
before the repair or service. It is a good idea for you to
make a record of the odometer reading before the repair/
service, so that you can be sure that it is properly reset, or
that the door jamb sticker is accurate if the odometer
must be reset at zero.
When the appropriate conditions exist, this display
shows the Electronic Vehicle Information Center (EVIC)
messages. Refer to “Electronic Vehicle Information Cen-
ter”.
11. Tire Pressure Monitoring Telltale Light
Each 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 vehiclehas 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.
Accordingly, when the low tire pressure telltale illumi-
nates, you should stop and check your tires as soon as
possible, and inflate them to the proper 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.
Please note that the TPMS is not a substitute for proper
tire maintenance, and it is the driver ’s responsibility to
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UNDERSTANDING YOUR INSTRUMENT PANEL 287

▫Full Size Spare – If Equipped............ 423
▫Limited-Use Spare – If Equipped......... 423
▫TireSpinning ....................... 424
▫Tread Wear Indicators................. 424
▫LifeOfTire ........................ 425
▫Replacement Tires.................... 426
Tire Rotation Recommendations........... 427
Tire Pressure Monitor System (TPMS)....... 428
▫Premium System.................... 431
▫General Information.................. 435
Fuel Requirements..................... 435
▫6.4L Engine........................ 435
▫Reformulated Gasoline................ 436▫Gasoline/Oxygenate Blends............. 436
▫E-85 Usage In Non-Flex Fuel Vehicles...... 437
▫MMT In Gasoline.................... 437
▫Materials Added To Fuel............... 438
▫Fuel System Cautions................. 438
▫Carbon Monoxide Warnings............ 439
Adding Fuel......................... 440
▫Fuel Filler Cap (Gas Cap).............. 440
▫Loose Fuel Filler Cap Message........... 443
Vehicle Loading...................... 443
▫Certification Label................... 443
TrailerTowing ........................ 446
▫Common Towing Definitions............ 446
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STARTING AND OPERATING 373

WARNING! (Continued)
•Unequal tire pressures from one side of the ve-
hicle to the other can cause the vehicle to drift to
the right or left.
•Always drive with each tire inflated to the recom-
mended cold tire inflation pressure.
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 resulting in higher fuel
consumption.
Ride Comfort And Vehicle Stability
Proper tire inflation contributes to a comfortable ride.
Over-inflation produces a jarring and uncomfortable
ride. Both under-inflation and over-inflation affect thestability of the vehicle and can produce a feeling of
sluggish response or over responsiveness in the steering.
Unequal tire pressures can cause erratic and unpredict-
able steering response.
Unequal tire pressure from side to side may cause the
vehicle to drift left or right.
Tire Inflation Pressures
The proper cold tire inflation pressure is listed on the
driver’s side “B” Pillar or rear edge of the driver’s side
door.
The pressure should be checked and adjusted, as well as
inspected for signs of tire wear or visible damage, at least
once a month. Use a good quality pocket-type gauge to
check tire pressure. Do not make a visual judgement
when determining proper inflation. Radial tires may look
properly inflated even when they are under-inflated.5
STARTING AND OPERATING 419

be ON. In this situation, the Tire Pressure Monitoring
Telltale Light will turn OFF only after the tires have been
inflated to the vehicle’s recommended cold tire pressure
value.
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
equipment that is not of the same size, type, and/or
style. Aftermarket wheels can cause sensor dam-
age. Do not use aftermarket tire sealants or balance
beads if your vehicle is equipped with a TPMS, as
damage to the sensors may result.
(Continued)
CAUTION! (Continued)
•After inspecting or adjusting the tire pressure
always reinstall the valve stem cap. This will
prevent moisture and dirt from entering the valve
stem, which could damage the Tire Pressure Moni-
toring Sensor.
NOTE:
•The TPMS is not intended to replace normal tire care
and maintenance, or 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.
430 STARTING AND OPERATING

General Information
This device complies with part 15 of the FCC rules and
RSS 210 of Industry Canada. Operation is subject to the
following conditions:
•This device may not cause harmful interference.
•This device must accept any interference received,
including interference that may cause undesired
operation.
The tire pressure sensors are covered under one of the
following licenses:
United States...................MRXC4W4MA4
Canada.....................2546A-C4W4MA4
FUEL REQUIREMENTS
6.4L Engine
The 6.4L engine is designed to meet all
emissions regulations and provide excel-
lent fuel economy and performance when
using high-quality premium unleaded
gasoline with an octane rating of 91 or
higher.
Light spark knock at low engine speeds is not harmful to
your engine. However, continued heavy spark knock at
high speeds can cause damage and immediate service is
required. Poor quality gasoline can cause problems such
as hard starting, stalling, and hesitations. If you experi-
ence these symptoms, try another brand of gasoline
before considering service for the vehicle.
Over 40 auto manufacturers worldwide have issued and
endorsed consistent gasoline specifications (the World-
wide Fuel Charter, WWFC) which define fuel properties
5
STARTING AND OPERATING 435

Gross Vehicle Weight Rating (GVWR)
The GVWR is the total permissible weight of your vehicle
including driver, passengers, vehicle, options, trailer
tongue weight, and cargo. The label also specifies maxi-
mum capacities of front and rear axle systems (GAWR).
Total load must be limited, so GVWR, and front and rear
GAWR are not exceeded.
Payload
The payload of a vehicle is defined as the allowable load
weight a truck or any given vehicle can carry, including
the weight of the driver, all passengers, options and
cargo.
Gross Axle Weight Rating (GAWR)
The GAWR is the maximum permissible load on the front
and rear axles. The load must be distributed in the cargo
area so that the GAWR of each axle is not exceeded.
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
444 STARTING AND OPERATING

CAUTION! (Continued)
•Your vehicle has been built with improved fluids
that protect the performance and durability of
your vehicle and also allow extended maintenance
intervals. Do not use chemical flushes in these
components as the chemicals can damage your
engine, transmission, power steering or air condi-
tioning. Such damage is not covered by the New
Vehicle Limited Warranty. If a flush is needed
because of component malfunction, use only the
specified fluid for the flushing procedure.
Engine Oil
Checking Oil Level
To assure proper engine lubrication, the engine oil must
be maintained at the correct level. Check the oil level at
regular intervals, such as every fuel stop. The best time tocheck the engine oil level is about five minutes after a
fully warmed 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. Maintain
the oil level in the “SAFE” range. Adding one quart of oil
when the reading is at the bottom of the “SAFE” range
will result in an oil level at the top of the “SAFE” range
on these engines.
NOTE:Fill engine oil one quart at a time.
CAUTION!
•Overfilling or underfilling will cause oil aeration
or loss of oil pressure. This could damage your
engine.
(Continued)
476 MAINTAINING YOUR VEHICLE