2008 JEEP GRAND CHEROKEE spare tire

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
330 STARTING AND OPERATING

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.
STARTING AND OPERATING 331
5

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.
332 STARTING AND OPERATING

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
334 STARTING AND OPERATING

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.
STARTING AND OPERATING 335
5

3. GAWR
4. Tongue weight rating for the trailer hitch utilized
(This requirement may limit the ability to always
achieve the 10% to 15% range of tongue weight as a
percentage of total trailer weight).
Towing Requirements Ð Tires
þ
Do not attempt to tow a trailer while using a compact
spare tire.
þProper tire inflation pressures are essential to the safe
and satisfactory operation of your vehicle. Refer to the
ªTires±General Informationº section of this manual for
proper tire inflation procedures.
þAlso, check the trailer tires for proper tire inflation
pressures before trailer usage.
þCheck for signs of tire wear or visible tire damage
before towing a trailer. Refer to the ªTires±General
Informationº section of this manual for the proper
inspection procedure.
þWhen replacing tires, refer to the ªTires±General Infor-
mationº section of this manual for proper tire replace-
ment procedures. Replacing tires with a higher load
carrying capacity will not increase the vehicle's GVWR
and GAWR limits.
Towing Requirements Ð Trailer Brakes
þ
Donotinterconnect the hydraulic brake system or
vacuum system of your vehicle with that of the trailer.
This could cause inadequate braking and possible
personal injury.
360 STARTING AND OPERATING

WHAT TO DO IN EMERGENCIES
CONTENTS
mHazard Warning Flashers.................370
mIf Your Engine Overheats.................371
mJacking And Tire Changing................372
NJack Location........................372
NSpare Tire Stowage....................373
NSpare Tire Removal....................373
NPreparations For Jacking................374NJacking Instructions....................375
mJump Starting.........................378
mEmergency Tow Hooks Ð If Equipped........381
mTowing A Disabled Vehicle................382
N2WD Models Only....................382
N4WD Models Only....................382
6

Spare Tire Stowage
The spare tire is stowed under the rear of the vehicle by
means of a cable winch mechanism. To remove or stow
the spare, use the jack handle to rotate the ªspare tire
driveº nut. The nut is located under a plastic cover at the
center-rear of the cargo floor area, just inside the liftgate
opening.
CAUTION!
Do not use power tools to winch the tire up or down.
Impact type tools can damage the winch mechanism.
Spare Tire Removal
Fit the jack handle extension over the drive nut. Use the
Lug Wrench to rotate the nut counter clockwise until the
spare is on the ground with enough slack in the cable to
allow to pull the tire out from under the vehicle.
Lowering/Raising Spare Tire
WHAT TO DO IN EMERGENCIES 373
6