2012 JEEP GRAND CHEROKEE wheel size

•If your liftgate is power closing and you
put the vehicle in gear, the liftgate will
continue to power close. However, ve-
hicle movement may result in a detection
of an obstruction.
WARNING!
•Driving with the liftgate open can allow
poisonous exhaust gases into your vehicle.
You and your passengers could be injured
by these fumes. Keep the liftgate closed
when you are operating the vehicle.
• If you are required to drive with the liftgate
open, make sure that all windows are
closed, and the climate control blower
switch is set at high speed. Do not use the
recirculation mode.
Gas props support the liftgate in the open
position. However, because the gas pressure
drops with temperature, it may be necessary to
assist the props when opening the liftgate in
cold weather.
OCCUPANT RESTRAINTSSome of the most important safety features in
your vehicle are the restraint systems:
• Three-point lap and shoulder belts for the
driver and all passengers
• Advanced Front Air Bags for driver and front
passenger
• Supplemental Active Head Restraints (AHR)
located on top of the front seats (integrated
into the head restraint)
• Supplemental Driver Side Knee Air Bag
• Supplemental Side Air Bag Inflatable Cur-
tains (SABIC) for the driver and passengers
seated next to a window
• Supplemental Seat-Mounted Side Air Bags
(SAB)
• An energy-absorbing steering column and
steering wheel
• Knee bolsters/blockers for front seat occu-
pant •
Front seat belts incorporate pretensioners
that may enhance occupant protection by
managing occupant energy during an im-
pact event
• All seat belt systems (except the driver’s and
front passenger) include Automatic Locking
Retractors (ALRs), which lock the seat belt
webbing into position by extending the belt
all the way out and then adjusting the belt to
the desired length to restrain a child seat or
secure a large item in a seat — if equipped
If you will be carrying children too small for
adult-sized seat belts, the seat belts or the
ISOFIX feature also can be used to hold infant
and child restraint systems. Refer to ISOFIX —
Child Seat Anchorage System for more infor-
mation.
NOTE:
The Advanced Front Air Bags have a multi-
stage inflator design. This allows the air bag
to have different rates of inflation based on
the severity and type of collision.
Please pay close attention to the information in
this section. It tells you how to use your restraint
29

Driver And Passenger Advanced Front Air
Bag Inflator Units
The Driver and Passenger Advanced Front Air
Bag Inflator Units are located in the center of
the steering wheel and on the right side of the
instrument panel. When the ORC detects a
collision requiring the Advanced Front Air
Bags, it signals the inflator units. A large quan-
tity of non-toxic gas is generated to inflate the
Advanced Front Air Bags. Different air bag
inflation rates are possible, based on the colli-
sion type and severity. The steering wheel hub
trim cover and the upper right side of the
instrument panel separate and fold out of the
way as the air bags inflate to their full size. The
air bags fully inflate in about 50 to 70 millisec-
onds. This is about half of the time it takes to
blink your eyes. The air bags then quickly
deflate while helping to restrain the driver and
front passenger.
The Advanced Front Air Bag gas is vented
through the vent holes in the sides of the air
bag. In this way, the air bags do not interfere
with your control of the vehicle.Supplemental Driver Side Knee Air Bag
Inflator Unit
The Supplemental Driver Side Knee Air Bag
unit is located in the instrument panel trim
beneath the steering column. When the ORC
detects a collision requiring the air bag, it
signals the inflator units. A large quantity of
non-toxic gas is generated to inflate the
Supplemental Driver Side Knee Air Bag. The
trim cover separates and folds out of the way
allowing the air bag to inflate to the full size. The
air bag fully inflates in about 15 to 20 millisec-
onds.
Supplemental Seat-Mounted Side Air Bag
(SAB) Inflator Units
The Supplemental Seat-Mounted Side Air Bags
are designed to activate only in certain side
collisions.
The ORC determines if a side collision requires
the side air bags to inflate, based on the
severity and type of collision.
Based on the severity and type of collision, the
side air bag inflator on the crash side of the
vehicle may be triggered, releasing a quantity
of non-toxic gas. The inflating SAB exitsthrough the seat seam into the space between
the occupant and the door. The SAB fully inflate
in about 10 milliseconds. The side air bag
moves at a very high speed and with such a
high force that it could injure you if you are not
seated properly, or if items are positioned in the
area where the side air bag inflates. This espe-
cially applies to children.
Supplemental Side Air Bag Inflatable
Curtain (SABIC) Inflator Units
During collisions where the impact is confined
to a particular area of the side of the vehicle,
the ORC may deploy the SABIC air bags,
depending on the severity and type of collision.
In these events, the ORC will deploy the SABIC
only on the impact side of the vehicle.
A quantity of non-toxic gas is generated to
inflate the side curtain air bag. The inflating
side curtain air bag pushes the outside edge of
the headliner out of the way and covers the
window. The air bag inflates in about 30 milli-
seconds (about one-quarter of the time that it
takes to blink your eyes) with enough force to
injure you if you are not belted and seated
properly, or if items are positioned in the area
where the side curtain air bag inflates. This
43

As an added safety feature, your vehicle has
been equipped with a Tire Pressure Monitoring
System (TPMS) that illuminates a low tire pres-
sure telltale when one or more of your tires is
significantly under-inflated. Accordingly, when
the low tire pressure telltale illuminates, you
should stop and check your tires as soon as
possible, and inflate them to the proper pres-
sure. 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 maintain correct tire pressure,
even if under-inflation has not reached the level
to trigger illumination of the TPMS low tire
pressure telltale.Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate when
the system is not operating properly. The TPMS
malfunction indicator is combined with the low
tire pressure telltale. When the system detects
a malfunction, the telltale will flash for approxi-
mately one minute and then remain continu-
ously illuminated. This sequence will continue
upon subsequent vehicle start-ups as long as
the malfunction exists. When the malfunction
indicator is illuminated, the system may not be
able to detect or signal low tire pressure as
intended. TPMS malfunctions may occur for a
variety of reasons, including the installation of
replacement or alternate tires or wheels on the
vehicle that prevent the TPMS from functioning
properly. Always check the TPMS malfunction
telltale after replacing one or more tires or
wheels on your vehicle, to ensure that the
replacement or alternate tires and wheels allow
the TPMS to continue to function properly.CAUTION!
The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures
and warning have been established for the tire
size equipped on your vehicle. Undesirable
system operation or sensor damage may re-
sult 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 tire sealant from a can or
balance beads if your vehicle is equipped with
a TPMS, as damage to the sensors may
result.
12. Park/Headlight ON Indicator — If
Equipped This indicator will illuminate when
the park lights or headlights are
turned on.
161

When additional traction is required, the 4WD
LOW position can be used to lock the front and
rear driveshafts together and force the front
and rear wheels to rotate at the same speed.
The 4WD LOW position is intended for loose,
slippery road surfaces only. Driving in the 4WD
LOW position on dry, hard-surfaced roads may
cause increased tire wear and damage to
driveline components.
When operating your vehicle in 4WD LOW, the
engine speed is approximately three times that
of the 4WD HI position at a given road speed.
Take care not to overspeed the engine and do
not exceed 25 mph (40 km/h).
Proper operation of four-wheel drive vehicles
depends on tires of equal size, type, and
circumference on each wheel. Any difference
will adversely affect shifting and cause damage
to the transfer case.
Because four-wheel drive provides improved
traction, there is a tendency to exceed safe
turning and stopping speeds. Do not go faster
than road conditions permit.WARNING!
You or others could be injured if you leave the
vehicle unattended with the transfer case in
the N (Neutral) position without first fully en-
gaging the parking brake. The transfer case N
(Neutral) position disengages both the front
and rear driveshafts from the powertrain and
will allow the vehicle to move regardless of the
transmission position. The parking brake
should always be applied when the driver is
not in the vehicle.
Shift Positions
For additional information on the appropriate
use of each transfer case mode position, see
the information below:
4WD AUTO
This range is used on surfaces such as ice,
snow, gravel, sand, and dry hard pavement.NOTE:
Refer to “Selec-Terrain
– If Equipped” in
“Starting and Operating” for further infor-
mation on the various positions and their
intended usages.
NEUTRAL
This range disengages both the front and rear
driveshafts from the powertrain. It is to be used
for flat towing behind another vehicle. Refer to
“Recreational Towing” in “Starting and Operat-
ing” for further information.
4WD LOW
This range is for low speed four-wheel drive. It
locks the front and rear driveshafts together
and forces the front and rear wheels to rotate at
the same speed. It provides additional traction
and maximum pulling power for loose, slippery
road surfaces only. Do not exceed 25 mph
(40 km/h).
NOTE:
Refer to “Selec-Terrain – If Equipped” for
further information on the various positions
and their intended usages.
232

WARNING!
Fast spinning tires can be dangerous. Forces
generated by excessive wheel speeds may
cause tire damage or failure. A tire could
explode and injure someone. Do not spin your
vehicle’s wheels faster than 30 mph (48 km/h)
when you are stuck, and do not let anyone
near a spinning wheel, no matter what the
speed.
Tire ChainsUse of traction devices require sufficient tire-to-
body clearance. Follow these recommenda-
tions to guard against damage.
•Install on Rear Tires Only
• Due to limited clearance, use SAE class “S”
low profile cables or traction devices only.
Security Chain Company (SCC) Super Z6
#SZ 441 cables or equivalent are recom-
mended.
WARNING!
Using tires of different size and type (M+S,
Snow) between front and rear axles can
cause unpredictable handling. You could lose
control and have a collision.
CAUTION!
To avoid damage to your vehicle or tires,
observe the following precautions:
• Because of restricted traction device clear-
ance between tires and other suspension
components, it is important that only trac-
tion devices in good condition are used.
Broken devices can cause serious dam-
age. Stop the vehicle immediately if noise
occurs that could indicate device breakage.
Remove the damaged parts of the device
before further use.
• Install device as tightly as possible and
then retighten after driving about 0.5 mile
(0.8 km).
• Do not exceed 30 mph (48 km/h).
(Continued)
CAUTION!(Continued)
• Drive cautiously and avoid severe turns
and large bumps, especially with a loaded
vehicle.
• Do not drive for prolonged period on dry
pavement.
• Observe the traction device manufacturer’s
instructions on the method of installation,
operating speed, and conditions for use.
Always use the suggested operating speed
of the device manufacturer’s if it is less than
30 mph (48 km/h).
• Do not use traction devices on a compact
spare tire.
Treadwear IndicatorsThese indicators are narrow strips 1/16 in
(1.6 mm) thick and are found in the tread
pattern grooves.
When the tread pattern is worn down to these
treadwear indicators, the tires should be re-
placed.
254

Overloading your vehicle, long trips in very hot
weather, and driving on bad roads may result in
greater wear.
Life Of TireThe service life of a tire is dependent upon
varying factors including but not limited to:
•Driving style
• Tire pressure
• Distance driven
WARNING!
Tires and the spare tire should be replaced
after six years, regardless of the remaining
tread. Failure to follow this warning can result
in sudden tire failure. You could lose control
and have an accident resulting in serious
injury or death.
Keep unmounted tires in a cool, dry place with
as little exposure to light as possible. Protect
tires from contact with oil, grease and gasoline.
Replacement TiresThe tires on your new vehicle provide a balance
of many characteristics. They should be in-
spected regularly for wear and correct inflation
pressure. The manufacturer strongly recom-
mends that you use tires equivalent to the
originals in quality and performance when re-
placement is needed (see section on tread
wear indicators). Failure to use equivalent re-
placement tires may adversely affect the safety,
handling and ride of your vehicle. We recom-
mend that you contact your local authorized
dealer on any questions you may have on tire
specifications or capability.
WARNING!
• Do not use a tire, wheel size or rating other
than that specified for your vehicle. Some
combinations of unapproved tires and
wheels may change suspension dimen-
sions and performance characteristics, re-
sulting in changes to steering, handling,
and stress to steering and suspension
components. You could lose control and
have an accident resulting in serious injury
or death. Use only the tire and wheel sizes
with load ratings approved for your vehicle.
• Never use a tire smaller than the minimum
tire size listed on your vehicle’s tire placard
unless explicitly instructed to do so by the
vehicle manufacturer (reference tire chain
information in this manual). Using an
under-sized tire could result in tire over-
loading and failure.
•
Failure to equip your vehicle with tires having
adequate speed capability can result in sud-
den tire failure and loss of vehicle control.
(Continued)
1—WornTire
2 — New Tire
255

TIRE PRESSURE MONITOR SYSTEM
(TPMS)
The Tire Pressure Monitoring System (TPMS)
will warn the driver of a low tire pressure based
on the vehicle recommended cold tire pressure.
The tire pressure will vary with temperature by
about 1 psi (7 kPa) for every 12°F (6.5°C). This
means that when the outside temperature de-
creases, the tire pressure will decrease. Tire
pressure should always be set based on cold
inflation tire pressure. This is defined as the tire
pressure after the vehicle has not been driven
for at least three hours, or driven less than
1 mile (1.6 km) after a three-hour period.Refer
to “Tires – General Information” in “Starting
and Operating” for information on how to
properly inflate the vehicle’s tires. The tire
pressure will also increase as the vehicle is
driven - this is normal and there should be no
adjustment for this increased pressure.
The TPMS will warn the driver of a low tire
pressure if the tire pressure falls below the low
pressure warning threshold for any reason,
including low temperature effects, or natural
pressure loss through the tire. The TPMS will continue to warn the driver of low
tire pressure as long as the condition exists,
and will not turn off until the tire pressure is at or
above recommended cold tire pressure. Once
the “TPM Telltale Light” and the “TIRE LOW
PRESSURE” message appears, the tire pres-
sure must be increased to the recommended
cold tire pressure in order for the ”TPM Telltale
Light” and the “TIRE LOW PRESSURE” mes-
sage to be turned off. The system will automati-
cally update and the “TPM Telltale Light” and
the “TIRE LOW PRESSURE” message will turn
off once the updated tire pressures have been
received. The vehicle may need to be driven for
up to 20 minutes above 15 mph (24 km/h) to
receive this information.
For example, your vehicle has a recommended
cold (parked for more than three hours) tire
pressure of 33 psi (227 kPa). If the ambient
temperature is 68°F (20°C) and the measured
tire pressure is 28 psi (193 kPa), a temperature
drop to 20°F (-7°C) will decrease the tire pres-
sure to approximately 24 psi (165 kPa). This tire
pressure is sufficiently low enough to display
the “TPM Telltale Light” and the “TIRE LOW
PRESSURE” message. Driving the vehicle maycause the tire pressure to rise to approximately
28 psi (193 kPa), but the “TPM Telltale Light”
and the “TIRE LOW PRESSURE” message will
still display. In this situation, the “TPM Telltale
Light” and the “TIRE LOW PRESSURE” mes-
sage 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. Unde-
sirable 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.
(Continued)
257