2009 JEEP GRAND CHEROKEE Engine light

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 if the
gasoline contains MMT.
It is even more important to look for gasoline 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.
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 normalconditions 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:
•The use of leaded gas is prohibited by Federal law.
Using leaded gasoline can impair engine performance
and damage the emission control system.
•An 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 authorized dealer for service assistance.
358 STARTING AND OPERATING

WARNING!
•Never have any smoking materials lit in or near
the vehicle when the gas cap is removed or the
tank filled.
•Never add fuel when the engine is running. This is
in violation of most state and federal fire regula-
tions and will cause the malfunction indicator
light to turn on.
NOTE:Tighten the gas cap about one-quarter turn until
you hear one click. This is an indication that the cap is
properly tightened.
If the gas cap is not tighten properly, the Malfunction
Indicator Light will come on. Be sure the gas cap is
tightened every time the vehicle is refueled.
WARNING!
A fire may result if gasoline is pumped into a
portable container that is inside of a vehicle. You
could be burned. Always place gas containers on the
ground while filling.
Loose Fuel Filler Cap Message
If the vehicle diagnostic system determines that the fuel
filler cap is loose, improperly installed, or damaged, a
“CHECK GASCAP” message will be displayed in the
EVIC (Electronic Vehicle Information Center). Refer to
“Electronic Vehicle Information Center” in Section 4 of
this manual. Tighten the fuel filler cap until a “clicking”
sound is heard. This is an indication that the fuel filler
cap is properly tightened. Refer to “Onboard Diagnostic
System — OBDII” in Section 7 of this manual for more
information.
366 STARTING AND OPERATING

Towing Tips
Before setting out on a trip, practice turning, stopping
and backing the trailer in an area away from heavy
traffic.
Automatic Transmission
The DRIVE range can be selected when towing. How-
ever, if frequent shifting occurs while in this range, the
TOW/HAUL mode (if equipped), or a lower gear range,
should be selected.
NOTE:Using the TOW/HAUL mode (if equipped), or a
lower gear range while operating the vehicle under
heavy operating conditions, will improve performance
and extend transmission life by reducing excessive shift-
ing and heat buildup. This action will also provide better
engine braking.The transmission fluid and filter should be changed if
you REGULARLY tow a trailer for more than 45 minutes
of continuous operation. Refer to the “Maintenance
Schedule” in Section 8 of this manual for proper mainte-
nance intervals.
NOTE:Check the transmission fluid level before towing
(4.7L and 5.7L engines).
Electronic Speed Control — If Equipped

Do not use in hilly terrain or with heavy loads.
When using the speed control, if you experience speed
drops greater than 10 mph (16 km/h), disengage until
you can get back to cruising speed.
Use speed control in flat terrain and with light loads to
maximize fuel efficiency.
STARTING AND OPERATING 381
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ONBOARD DIAGNOSTIC SYSTEM — OBD II
Your vehicle is equipped with a sophisticated onboard
diagnostic system called OBD II. This system monitors
the performance of the emissions, engine, and automatic
transmission control systems. When these systems are
operating properly, your vehicle will provide excellent
performance and fuel economy, as well as engine emis-
sions well within current government regulations.
If any of these systems require service, the OBD II system
will turn on the “Malfunction Indicator Light.” It will
also store diagnostic codes and other information to
assist your service technician in making repairs. Al-
though your vehicle will usually be drivable and not
need towing, see your authorized dealer for service as
soon as possible.CAUTION!
•Prolonged driving with the “Malfunction Indica-
tor Light” on could cause further damage to the
emission control system. It could also affect fuel
economy and drivability. The vehicle must be
serviced before any emissions tests can be per-
formed.
•If the “Malfunction Indicator Light” is flashing
while the engine is running, severe catalytic con-
verter damage and power loss will soon occur.
Immediate service is required.
Loose Fuel Filler Cap Message
After fuel is added, the vehicle diagnostic system can
determine if the fuel filler cap is loose, improperly
installed, or damaged. A “CHECK GASCAP” message
will be displayed in the EVIC (Refer to Section 4 of this
410 MAINTAINING YOUR VEHICLE

manual). Tighten the gas cap until aclickingsound is
heard. This is an indication that the gas cap is properly
tightened.
The message will remain displayed until the vehicle
diagnostic system can retest the fuel system. The test will
perform the next time the vehicle is started, if the vehicle
was keyed off above 40°F (4°C) outside temperature and
the following vehicle start is above 40°F (4°C) outside
temperature. It may be possible to have a message that
will not clear due to the test being disabled due to low
outside temperatures. If the test is performed and the
problem is gone, the message will disappear.
If the problem persists, the message will appear the next
time the vehicle is started. This might indicate a damaged
cap. If the problem is detected twice in a row, the system
will turn on the Malfunction Indicator Light (MIL).
Resolving the problem will turn the MIL light off. See
your authorized dealer for service.EMISSIONS INSPECTION AND MAINTENANCE
PROGRAMS
In some localities, it may be a legal requirement to pass
an inspection of your vehicle’s emissions control system.
Failure to pass could prevent vehicle registration.
For states that require an Inspection and Mainte-
nance (I/M), this check verifies the Malfunction
Indicator Light (MIL) is functioning and is not on
when the engine is running, and that the OBD II system
is ready for testing.
Normally, the OBD II system will be ready. The OBD II
system maynotbe ready if your vehicle was recently
serviced, recently had a dead battery or a battery replace-
ment. If the OBD II system should be determined not
ready for the I/M test, your vehicle may fail the test.
MAINTAINING YOUR VEHICLE 411
7

Windshield Wiper Blades
Clean the rubber edges of the wiper blades and the
windshield periodically with a sponge or soft cloth and a
mild nonabrasive cleaner to remove accumulations of salt
or road film.
Operation of the wipers on dry glass for long periods
may cause deterioration of the wiper blades. Always use
washer fluid when using the wipers to remove salt or dirt
from a dry windshield.
Avoid using the wiper blades to wipe frost or ice from the
windshield. Keep the blade rubber out of contact with
petroleum products such as engine oil, gasoline, etc.
Adding Washer Fluid
On vehicles equipped with a Electronic Vehicle Informa-
tion Center (EVIC), the low washer fluid level will be
indicated. When the sensor detects a low fluid level, the
windshield will light on the vehicle graphic outline and
the “WASHER FLUID LOW” message will be displayed.The fluid reservoir for the windshield washers and the
rear window washer is shared. The fluid reservoir is
located in the engine compartment, be sure to check the
fluid level at regular intervals. Fill the reservoir with
windshield washer solvent only (not radiator antifreeze).
When refilling the washer fluid reservoir, take some
washer fluid and apply it to a cloth or towel and wipe
clean the wiper blades, this will help blade performance.
To prevent freeze-up of your windshield washer system
in cold weather, select a solution or mixture that meets or
exceeds the temperature range of your climate. This
rating information can be found on most washer fluid
containers.
MAINTAINING YOUR VEHICLE 421
7

if it has been 6 months since your last oil change even
if the oil change indicator message is NOT illumi-
nated.
•Change your engine oil more often if you drive your
vehicle off-road for an extended period of time.
•Under no circumstances should oil change intervals
exceed 6,000 miles (10,000 km) or 6 months, whichever
comes first.
Your authorized dealer will reset the oil change indicator
message after completing the scheduled oil change. If this
scheduled oil change is performed by someone other
than your authorized dealer the message can be reset by
referring to the steps described under ”Electronic Vehicle
Information Center” in Section 4 of this manual.
At Each Stop for Fuel
•Check the engine oil level about 5 minutes after a fully
warmed engine is shut off. Checking the oil level whilethe vehicle is on level ground will improve the accu-
racy of the oil level reading. Add oil only when the
level is at or below the ADD or MIN mark.
•Check the windshield washer solvent and add if
required.
Once a Month
•Check tire pressure and look for unusual wear or
damage.
•Inspect the battery and clean and tighten the terminals
as required.
•Check the fluid levels of the coolant reservoir, brake
master cylinder, power steering and transmission
(4.7L and 5.7L only) and add as needed.
•Check all lights and other electrical items for correct
operation.
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•Check the windshield washer solvent and add if
required.
Once a Month
•Check tire pressure and look for unusual wear or
damage.
•Inspect the battery and clean and tighten the terminals
as required.
•Check the fluid levels of the coolant reservoir, brake
master cylinder, and power steering and add as
needed.
•Check all lights and other electrical items for correct
operation.
At Each Oil Change
•Change the engine oil filter.
•Inspect the brake hoses and lines.
•Inspect for the presence of water in the fuel filter/
water separator unit.
CAUTION!
Failure to perform the required maintenance items
may result in damage to the vehicle.
Required Maintenance Intervals
Refer to the Maintenance Schedules on the following
pages for the required maintenance intervals.
MAINTENANCE SCHEDULES 477
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