2008 JEEP GRAND CHEROKEE tires

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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10 minutes above 15 mph (24 km/h) will turn OFF the
ªTire Pressure Monitoring Telltale Lightº as long as none
of the road tires are below the low pressure warning
threshold.
NOTE: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 and the ªTire
Pressure Monitoring Telltale Lightº will turn ON. After
driving the vehicle for up to 10 minutes above 15 mph (25
km/h), the ªTire Pressure Monitoring Telltale Lightº will
flash on and off for 75 seconds and then remain on solid.
For each subsequent ignition key cycle, a chime will
sound and the ªTire Pressure Monitoring Telltale Lightº
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 ªTire Pressure
Monitoring Telltale Lightº 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 10 minutes above 15 mph (24 km/h)
in order for the TPMS to receive this information.
Premium 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.
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The Tire Pressure Monitor System (TPMS) consists of the
following components:
²Receiver Module
²4 Tire Pressure Monitoring Sensors
²3 Trigger Modules (mounted in three of the four wheel
wells)
²Various Tire Pressure Monitoring System Messages,
which display in the Electronic Vehicle Information
Center (EVIC), and a graphic displaying tire pressures
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 roadtires. A low spare tire will set the ªSPARE LOW PRES-
SUREº textual message, but it will not cause the ªTire
Pressure Monitoring Telltale Lightº to illuminate or the
chime to sound.
Tire Pressure Monitoring Low Pressure Warnings
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. In addition, the
Electronic Vehicle Information Center (EVIC) will display
one or more Low Pressure messages (Left Front, Left
Rear, Right Front, Right Rear) for 3 seconds, and a
graphic display of the pressure value(s) with the low
tire(s) flashing. Refer to ªElectronic Vehicle Information
Center (EVIC)º in Section 4 of this manual.
NOTE:Your system can be set to display pressure units
in PSI, kPa, or BAR.
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NOTE:Your system can be set to display pressure units
in PSI, kPa, or BAR.
If the ignition key is cycled, this sequence will repeat,
providing the system fault still exists. If the system fault
no longer exists, the Tire Pressure Monitoring Telltale
Light will no longer flash, the9CHECK TPM SYSTEM9text message will not be present, and a pressure value
will be displayed instead of dashes. 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
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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, a chime to sound, a Low Pressure message to appear
in the EVIC, and the graphic display will still show the
low tire pressure value flashing. Driving the vehicle for
up to 10 minutes above 15 mph (24 km/h) will turn OFF
the ªTire Pressure Monitoring Telltale Lightº as long as
none of road tires are below the low pressure warning
threshold. The EVIC will also display a ªSpare Low
Pressureº text message, and the graphic display will
show a tire pressure value in place of the flashing low tire
pressure value.
NOTE: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 thenext ignition key cycle, the ªTire Pressure Monitoring
Telltale Lightº will remain ON, a chime will sound, and
the EVIC will still display a flashing pressure value in the
graphic display. After driving the vehicle for up to 10
minutes above 15 mph (24 km/h), the ªTire Pressure
Monitoring Telltale Lightº will flash on and off for 75
seconds and then remain on solid. In addition, the EVIC
will display a9CHECK TPM SYSTEM9message for 3
seconds and then display dashes (- -) in place of the
pressure value. For each subsequent ignition key cycle, a
chime will sound, the ªTire Pressure Monitoring Telltale
Lightº will flash on and off for 75 seconds and then
remain on solid, and the EVIC will display a9CHECK
TPM SYSTEM9message for 3 seconds and then display
dashes (- -) in place of the pressure value. 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.
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