JEEP GRAND CHEROKEE 2008 WK / 3.G Owners Manual

Tire Pressures for High Speed Operation
The manufacturer advocates driving at safe speeds
within posted speed limits. Where speed limits or condi-
tions are such that the vehicle can be driven at high
speeds, maintaining correct tire inflation pressure is very
important. Increased tire pressure and reduced vehicle
loading may be required for high-speed vehicle opera-
tion. Refer to original equipment or an authorized tire
dealer for recommended safe operating speeds, loading
and cold tire inflation pressures.
WARNING!
High speed driving with your vehicle at or above
maximum load is dangerous. The added strain on
your tires could cause them to fail. You could have a
serious accident. Don't drive a vehicle loaded to the
maximum capacity at continuous speeds above 75
mph (120 km/h).
Radial-Ply Tires
WARNING!
Combining radial ply tires with other types of tires
on your vehicle will cause your vehicle to handle
poorly. The instability could cause an accident. Al-
ways use radial tires in sets of four. Never combine
them with other types of tires.
Cuts and punctures in radial tires are repairable only in
the tread area because of sidewall flexing. Consult your
dealer for radial tire repairs.
Tire Spinning
When stuck in mud, sand, snow, or ice conditions, do not
spin your vehicle's wheels above 35 mph (55 km/h).
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WARNING!
Fast spinning tires can be dangerous. Forces gener-
ated by excessive wheel speeds may cause tire dam-
age or failure. A tire could explode and injure some-
one. Do not spin your vehicle's wheels faster than 35
mph (55 km/h) when you are stuck, and do not let
anyone near a spinning wheel no matter what the
speed.
Tread Wear Indicators
Tread wear indicators are in the original equipment tires
to help you in determining when your tires should be
replaced.These indicators are molded into the bottom of the tread
grooves. They will appear as bands when the tread depth
becomes 1/16 inch (2 mm). When the indicators appear
in 2 or more adjacent grooves, the tire should be replaced.
Many states have laws requiring tire replacement at this
point.
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Life of Tire
The service life of a tire is dependent upon varying
factors including but not limited to:
²Driving style
²Tire pressure
²Distance driven
WARNING!
Tires and 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 dismounted tires in a cool, dry place with as little
exposure to light as possible. Protect tires from contact
with oil, grease, and gasoline.
Replacement Tires
The tires on your new vehicle provide a balance of many
characteristics. They should be inspected regularly for
wear and correct cold tire inflation pressure. The manu-
facturer strongly recommends that you use tires equiva-
lent to the originals in size, quality and performance
when replacement is needed (refer to the paragraph on
ªTread Wear Indicatorsº). Refer to the ªTire and Loading
Informationº placard for the size designation of your tire.
The service description and load identification will be
found on the original equipment tire. Failure to use
equivalent replacement tires may adversely affect the
safety, handling, and ride of your vehicle. We recommend
that you contact your original equipment or an autho-
rized tire dealer with any questions you may have on tire
specifications or capability.
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WARNING!
²Do not use a tire, wheel size or rating other than
that specified for your vehicle. Some combina-
tions of unapproved tires and wheels may change
suspension dimensions and performance charac-
teristics, resulting in changes to steering, han-
dling, and braking of your vehicle. This can cause
unpredictable 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.
²Never use a tire with a smaller load index or
capacity, other than what was originally equipped
on your vehicle. Using a tire with a smaller load
index could result in tire overloading and failure.
You could lose control and have an accident.
²Failure to equip your vehicle with tires having
adequate speed capability can result in sudden
tire failure and loss of vehicle control.
CAUTION!
Replacing original tires with tires of a different size
may result in false speedometer and odometer
readings.
Alignment and Balance
Poor suspension alignment may result in:
²Fast tire wear.
²Uneven tire wear, such as feathering and one-sided
wear.
²Vehicle pull to right or left.
Tires may also cause the vehicle to pull left or right.
Alignment will not correct this problem. See your autho-
rized dealer for proper diagnosis.
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Improper alignment will not cause vehicle vibration.
Vibration may be a result of tire and wheel out-of-
balance. Proper balancing will reduce vibration and
avoid tire cupping and spotty wear.
TIRE CHAINS
Certain models have sufficient tire-to-body clearance to
allow use of tire chains.Install chains on rear tires only.
Follow these recommendations to guard against damage
and excessive tire and chain wear:
²Do not install tire chains or traction devices on ve-
hicles with larger than P235/65R17 tires. Tires larger
than this may not provide sufficient body clearance
with chains or other traction devices.
²Use SAE class ªSº tire chains or traction devices only.
²Follow tire chain manufacturer's instructions for
mounting chains.
²Install chains snugly and tighten after 1/2 mile (1 km)
of driving.
²Do notexceed 30 mph (48 km/h), unless otherwise
specified by the chain manufacturer.
²Drive cautiously, avoiding large bumps, potholes and
extreme driving maneuvers.
TIRE ROTATION RECOMMENDATIONS
Tires on the front and rear axles of vehicles operate at
different loads and perform different steering, handling,
and braking functions. For these reasons, they wear at
unequal rates, and develop irregular wear patterns.
These effects can be reduced by timely rotation of tires.
The benefits of rotation are especially worthwhile with
aggressive tread designs such as those on On/Off Road
type tires. Rotation will increase tread life, help to main-
tain mud, snow, and wet traction levels, and contribute to
a smooth, quiet ride.
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Follow the recommended tire rotation frequency for your
type of driving found in the ªMaintenance Schedulesº
Section of this manual. More frequent rotation is permis-
sible if desired. The reasons for any rapid or unusual
wear should be corrected prior to rotation being per-
formed.
NOTE:The Premium Tire Pressure Monitor System will
automatically locate the pressure values displayed in the
correct vehicle position following a tire rotation.
The suggested rotation method is the ªforward-crossº
shown in the following diagram.
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 12ÉF (±11ÉC). This means that when
the outside temperature decreases, the tire pressure will
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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
3 hours, or driven less than 1 mile (1 km) after a 3 hour
period.Refer to the ªTires ± General Informationº in
this section 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 TPM System 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 tem-
perature effects, or natural pressure loss through the tire.
The TPM System 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 recom-
mended cold tire pressure. Once the low tire pressure
warning has been illuminated, the tire pressure must beincreased to the recommended cold tire pressure in order
for the ªTire Pressure Monitoring Telltale Lightº to be
turned off. The system will automatically update and the
ªTire Pressure Monitoring Telltale Lightº will extinguish
once the updated tire pressures have been received. The
vehicle may need to be driven for up to 10 minutes above
15 mph (24 km/h) to receive this information.
For example, your vehicle has a recommended cold
(parked for more than 3 hours) tire pressure of 33 psi (227
kPa). If the ambient temperature is 68ÉF (20ÉC) and the
measured tire pressure is 28 psi (193 kPa), a temperature
drop to 20ÉF (-7ÉC) will decrease the tire pressure to
approximately 24 psi (165 kPa). This tire pressure is
sufficiently low enough to turn ON the ªTire Pressure
Monitoring Telltale Light.º Driving the vehicle may cause
the tire pressure to rise to approximately 28 psi (193 kPa),
but the ªTire Pressure Monitoring Telltale Lightº will still
be ON. In this situation, the ªTire Pressure Monitoring
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Telltale Lightº 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 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:
²The TPMS is not intended to replace normal tire care
and maintenance, or to provide warning of a tire
failure or condition.
²The TPMS should not be used as a tire pressure gauge
while adjusting your tire pressure.
²Driving 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.
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²The TPMS is not a substitute for proper tire mainte-
nance, and it is the driver 's responsibility to maintain
correct tire pressure using an accurate tire gauge, even
if under-inflation has not reached the level to trigger
illumination of the ªTire Pressure Monitoring Telltale
Light.º
²Seasonal temperature changes will affect tire pressure,
and the TPM system will monitor the actual tire
pressure in the tire.
Base System Ð If Equipped
The Tire Pressure Monitor System (TPMS) uses wireless
technology with wheel rim mounted electronic sensors to
monitor tire pressure levels. Sensors, mounted to each
wheel as part of the valve stem, transmit tire pressure
readings to the Receiver Module.
NOTE:It is particularly important, for you to check the
tire pressure in all of your tires regularly and to maintain
the proper pressure.The Tire Pressure Monitor System (TPMS) consists of the
following components:
²Receiver Module
²4 Tire Pressure Monitoring Sensors
²Tire Pressure Monitoring Telltale Light
A tire pressure monitoring sensor is located in the spare
wheel if the vehicle is equipped with a matching full size
spare wheel and tire assembly. The matching full size
spare tire can be used in place of any of the four road
tires. A low spare tire will not cause the ªTire Pressure
Monitoring Telltale Lightº to illuminate or the chime to
sound.
The ªTire Pressure Monitoring Telltale Lightº will
illuminate in the instrument cluster, and an au-
dible chime will be activated when one or more of
the four active road tire pressures are low. Should this
occur, you should stop as soon as possible, check the
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inflation pressure of each tire on your vehicle, and inflate
each tire to the vehicle's recommended cold placard
pressure value. The system will automatically update
and the ªTire Pressure Monitoring Telltale Lightº will
extinguish once the updated tire pressures have been
received. The vehicle may need to be driven for up to 10
minutes above 15 mph (24 km/h) to receive this infor-
mation.
The ªTire Pressure Monitoring Telltale Lightº will flash
on and off for 75 seconds, and remain on solid when a
system fault is detected. The system fault will also sound
a chime. If the ignition key is cycled, this sequence will
repeat, providing the system fault still exists. The Tire
Pressure Monitoring Telltale Lamp will turn off when the
fault condition no longer exists. A system fault can occur
by any of the following scenarios:1. Jamming due to electronic devices or driving next to
facilities emitting the same Radio Frequencies as the TPM
sensors.
2. Installing some form of aftermarket window tinting
that affects radio wave signals.
3. Lots of snow or ice around the wheels or wheel
housings.
4. Using tire chains on the vehicle.
5. Using wheels/tires not equipped with TPM sensors.
NOTE:If your vehicle is equipped with a matching full
size spare wheel and tire assembly, it has a tire pressure
monitoring sensor, and can be monitored by the Tire
Pressure Monitoring System (TPMS). In the event that the
matching full size spare tire is swapped with a low
pressure road tire, the next ignition key cycle will still
show the ªTire Pressure Monitoring Telltale Lightº to be
ON, and a chime to sound. Driving the vehicle for up to
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