2008 JEEP COMMANDER Owners Manual

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.
STARTING AND OPERATING 329
5

NOTE:Your system can be set to display pressure units
in PSI, kPa, or BAR.
Should a low tire condition occur on any of the four
active road tire(s), you should stop as soon as possible,
and inflate the low tire(s) that is flashing on the graphic
display to the vehicle's recommended cold tire pressure.The system will automatically update, the graphic dis-
play of the pressure value(s) will stop flashing, and the
ªTire Pressure Monitoring Telltale Lightº will extinguish
once the updated tire pressure(s) 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.
Check TPM System Message
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. The EVIC will display a ªCHECK TPM SYS-
TEMº message for 3 seconds. This text message is then
followed by a graphic display, with ª- -ª in place of the
pressure value(s) indicating which Tire Pressure Moni-
toring Sensor(s) is not being received.
NOTE:Your system can be set to display pressure units
in PSI, kPa, or BAR.
330 STARTING AND OPERATING

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 SYSTEM9
text 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
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
STARTING AND OPERATING 331
5

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 the
next 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 10minutes 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.
In addition, the ªTire Pressure Monitoring Telltale Lightº
will turn OFF and the graphic in the EVIC will display a
new pressure value instead of dashes (- -), 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
332 STARTING AND OPERATING

be driven for up to 10 minutes above 15 mph (24 km/h)
in order for the TPMS to receive this information.
General Information
This device complies with part 15 of the FCC rules and
RSS 210 of Industry Canada. Operation is subject to the
following conditions:
²This device may not cause harmful interference.
²This device must accept any interference received,
including interference that may cause undesired op-
eration.
The tire pressure sensors are covered under one of the
following licenses:
United States.....................KR5S120123
Canada........................2671-S120123
FUEL REQUIREMENTS
3.7/4.7L Engines (If Equipped)
All engines (except 5.7L engines) are de-
signed to meet all emissions regulations
and provide excellent fuel economy and
performance when using high quality un-
leaded ªregularº gasoline having an oc-
tane rating of 87. The use of premium
gasoline is not recommended. Under normal conditions,
the use of premium gasoline will not provide a benefit
over high quality regular gasolines, and in some circum-
stances may result in poorer performance.
5.7L Engines (If Equipped)
The 5.7L engine is designed to meet all
emissions regulations and provide satisfac-
tory fuel economy and performance when
STARTING AND OPERATING 333
5

using high quality unleaded gasoline having an octane
range of 87 to 89. The manufacturer recommends the use
of 89 octane for optimum performance. The use of
premium gasoline is not recommended. Under normal
conditions, the use of premium gasoline will not provide
a benefit over high quality regular and mid-grade gaso-
lines, and in some circumstances may result in poorer
performance.
Light spark knock at low engine speeds is not harmful to
your engine. However, continued heavy spark knock at
high speeds can cause damage and immediate service is
required.
Poor quality gasoline can cause problems such as hard
starting, stalling and hesitations. If you experience these
symptoms, try another brand of gasoline before consid-
ering service for the vehicle.Over 40 auto manufacturer's world wide have issued and
endorsed consistent gasoline specifications (the World-
wide Fuel Charter, WWFC) to define fuel properties
necessary to deliver enhanced emissions, performance,
and durability for your vehicle. The manufacturer recom-
mends the use of gasoline that meets the WWFC speci-
fications if they are available.
Reformulated Gasoline
Many areas of the country require the use of cleaner
burning gasoline referred to as ªReformulated Gasoline.º
Reformulated gasoline contains oxygenates, and are spe-
cifically blended to reduce vehicle emissions and im-
prove air quality.
The manufacturer supports the use of reformulated gaso-
line. Properly blended reformulated gasoline will pro-
vide excellent performance and durability of engine and
fuel system components.
334 STARTING AND OPERATING

Gasoline/Oxygenate Blends
Some fuel suppliers blend unleaded gasoline with oxy-
genates such as 10% ethanol, MTBE, and ETBE. Oxygen-
ates are required in some areas of the country during the
winter months to reduce carbon monoxide emissions.
Fuels blended with these oxygenates may be used in
your vehicle.
CAUTION!
DO NOT use gasoline containing Methanol or E85
Ethanol. Use of these blends may result in starting
and driveability problems and may damage critical
fuel system components.
Problems that result from using methanol/gasoline
blends are not the responsibility of the manufacturer.
While MTBE is an oxygenate made from Methanol, it
does not have the negative effects of Methanol.
MMT In Gasoline
MMT is a manganese containing metallic additive that is
blended into some gasoline to increase octane. Gasoline
blended with MMT provides no performance advantage
beyond gasoline of the same octane number without
MMT. Gasoline blended with MMT reduces spark plug
life and reduces emission system performance in some
vehicles. The manufacturer recommends that gasoline
without MMT be used in your vehicle. The MMT content
of gasoline may not be indicated on the gasoline pump,
therefore, you should ask your gasoline retailer whether
or not his/her gasoline contains MMT.
It is even more important to look for gasolines without
MMT in Canada, because MMT can be used at levels
higher than those allowed in the United States.
MMT is prohibited in Federal and California reformu-
lated gasoline.
STARTING AND OPERATING 335
5

Materials Added To Fuel
All gasoline sold in the United States is required to
contain effective detergent additives. Use of additional
detergents or other additives is not needed under normal
conditions and would result in additional cost. Therefore
you should not have to add anything to the fuel.
Fuel System Cautions
CAUTION!
Follow these guidelines to maintain your vehicle's
performance:
²The use of leaded gas is prohibited by Federal law.
Using leaded gasoline can impair engine performance,
damage the emission control system.
²An out-of-tune engine, or certain fuel or ignition
malfunctions, can cause the catalytic converter to
overheat. If you notice a pungent burning odor or
some light smoke, your engine may be out of tune or
malfunctioning and may require immediate service.
Contact your dealer for service assistance.
²The use of fuel additives which are now being sold as
octane enhancers is not recommended. Most of these
products contain high concentrations of methanol.
Fuel system damage or vehicle performance problems
resulting from the use of such fuels or additives is not
the responsibility of the manufacturer.
NOTE:Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
336 STARTING AND OPERATING