2009 JEEP GRAND CHEROKEE Owners Manual

WARNING! (Continued)
•Failure 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 read-
ings.
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:
•Do 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.
•Use SAE class “S” tire chains or traction devices only.
•Follow tire chain manufacturer’s instructions for
mounting chains.
•Install chains snugly and tighten after 0.5 mile (1 km)
of driving.
•Do notexceed 30 mph (48 km/h), unless otherwise
specified by the chain manufacturer.
•Drive cautiously, avoiding large bumps, potholes and
extreme driving maneuvers.
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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.
The suggested rotation method is the “forward-cross”
shown in the following diagram.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.
Follow the recommended tire rotation frequency for your
type of driving. Refer to “Maintenance Schedules” in
Section 8 of this manual. More frequent rotation is
permissible if desired. The reasons for any rapid or
unusual wear should be corrected prior to rotation being
performed.
NOTE:The premium Tire Pressure Monitor System will
automatically locate the pressure values displayed in the
correct vehicle position following a tire rotation.
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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 (–11°C). This means that when
the outside temperature decreases, 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 km) after a
three-hour period.Refer to the “Tires – General Infor-
mation” 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 pres-
sure.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 low tire pressure warning has
been illuminated, the tire pressure must be increased to
the recommended cold tire pressure in order for the Tire
Pressure Monitoring Telltale Light to be turned off. The
system will automatically update and the Tire Pressure
Monitoring Telltale Light will extinguish once the up-
dated 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.
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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 tempera-
ture drop to 20°F (-7°C) will decrease the tire pressure to
approximately 24 psi (165 kPa). This tire pressure is
sufficiently low enough to turn ON the Tire Pressure
Monitoring Telltale Light. Driving the vehicle may cause
the tire pressure to rise to approximately 28 psi (193 kPa),
but the Tire Pressure Monitoring Telltale Light will still
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.
•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.
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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.
•The 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 Tire Pressure Monitoring Telltale
Light.
•Seasonal temperature changes will affect tire pressure,
and the TPMS will monitor the actual tire pressure in
the tire.
Base System
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 regularly
check the tire pressure in all of your tires, and to maintain
the proper pressure.
The TPMS consists of the following components:
•Receiver Module
•Four Tire Pressure Monitoring Sensors
•Tire Pressure Monitoring Telltale Light
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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 Tire Pressure
Monitoring Telltale Light to illuminate, a warning mes-
sage to appear, or the chime to sound.
The Tire Pressure Monitoring Telltale Light will
illuminate in the instrument cluster, a “TIRE LOW
PRESSURE” message will display in the instru-
ment cluster for 60 seconds, and an audible 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 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 Tire Pressure Monitor-
ing Telltale Light will extinguish, once the updated tirepressures 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.
The Tire Pressure Monitoring Telltale Light will flash on
and off for 75 seconds, and remain on solid when a
system fault is detected. In addition, a “CHECK TPM
SYSTEM” message will be displayed for 75 seconds when
a system fault is detected, and a chime will sound. If the
ignition key is cycled, this sequence will repeat, provid-
ing the system fault still exists. The Tire Pressure Moni-
toring Telltale Light will turn off when the fault condition
no longer exists. A system fault can occur by any of the
following:
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.
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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 Tire Pressure Monitoring Telltale Light to be
ON, a “TIRE LOW PRESSURE” message will be
displayed in the instrument cluster for 60 seconds, and
a chime to sound. Driving the vehicle for up to
20 minutes above 15 mph (24 km/h) will turn OFF theTire Pressure Monitoring Telltale Light as long as none
of the road tires are below the low pressure warning
threshold.
•If your vehicle is not equipped with a matching
full-size spare wheel and tire assembly, it does not
have a tire pressure monitoring sensor in the spare tire.
The TPMS will not be able to monitor the tire pressure.
If you install the spare tire, in place of a road tire, that
has a pressure below the low-pressure warning limit,
upon the next ignition key cycle, a chime will sound, a
“TIRE LOW PRESSURE” message will be displayed in
the instrument cluster for 60 seconds, and the Tire
Pressure Monitoring Telltale Light will turn ON. After
driving the vehicle for up to 20 minutes above 15 mph
(25 km/h), the Tire Pressure Monitoring Telltale Light
will flash on and off for 75 seconds and then remain on
solid. In addition, a “CHECK TPM SYSTEM” message
will be displayed for 75 seconds. For each subsequent
ignition key cycle, a chime will sound, a “CHECK
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TPM SYSTEM” message will be displayed for 75 sec-
onds, and the Tire Pressure Monitoring Telltale Light
will flash on and off for 75 seconds and then remain on
solid. Once you repair or replace the original road tire,
and reinstall it on the vehicle in place of the spare tire,
the TPMS will update automatically and the Tire
Pressure Monitoring Telltale Light will turn OFF, as
long as no tire pressure is below the low-pressure
warning limit in any of the four active road tires. The
vehicle may need to be driven for up to 20 minutes
above 15 mph (24 km/h) in order for the TPMS to
receive this information.
Premium System — 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 regularly
check the tire pressure in all of your tires and to maintain
the proper pressure.
The Tire Pressure Monitor System (TPMS) consists of the
following components:
•Receiver Module
•Four Tire Pressure Monitoring Sensors
•Three Trigger Modules (mounted in three of the four
wheel wells)
•Various Tire Pressure Monitoring System Messages,
which display in the Electronic Vehicle Information
Center (EVIC), and a graphic displaying tire pressures
•Tire 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
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