2009 JEEP GRAND CHEROKEE check engine

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.
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5

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

Your vehicle has a simple ignition key-actuated test,
which you can use prior to going to the test station. To
check if your vehicle’s OBD II system is ready, you must
do the following:
1. Insert your ignition key into the ignition switch.
2. Turn the ignition to the ON position, but do not crank
or start the engine.
3. If you crank or start the engine, you will have to start
this test over.
4. As soon as you turn your key to the ON position, you
will see the MIL symbol come on as part of a normal bulb
check.
5. Approximately 15 seconds later, one of two things will
happen:
a. The MIL will flash for about 10 seconds and then
return to being fully illuminated until you turn OFFthe ignition or start the engine. This means that your
vehicle’s OBD II system isnot readyand you should
notproceed to the I/M station.
b. The MIL will not flash at all and will remain fully
illuminated until you turn OFF the ignition or start the
engine. This means that your vehicle’s OBD II system
isreadyand you can proceed to the I/M station.
If your OBD II system isnot ready,you should see your
authorized dealer or repair facility. If your vehicle was
recently serviced or had a battery failure or replacement,
you may need to do nothing more than drive your
vehicle as you normally would in order for your OBD II
system to update. A recheck with the above test routine
may then indicate that the system is now ready.
Regardless of whether your vehicle’s OBD II system is
ready or not, if the MIL is illuminated during normal
vehicle operation you should have your vehicle serviced
412 MAINTAINING YOUR VEHICLE

operate satisfactorily without periodic maintenance.
However, if a malfunction of these items does occur, it
could adversely affect the engine or vehicle performance.
These items should be inspected if a malfunction is
observed or suspected.
Engine Oil
Checking Oil Level
To assure proper engine lubrication, the engine oil must
be maintained at the correct level. Check the oil level at
regular intervals, such as every fuel stop. The best time to
check the engine oil level is about five minutes after a
fully warmed engine is shut off, or before starting the
engine after it has sat overnight.
Checking the oil while the vehicle is on level ground will
improve the accuracy of the oil level readings. Maintain
the oil level in the SAFE level range. Adding 1 U.S. Quart(0.95L) of oil when the level is at the bottom of the SAFE
range will result in the level being at the top of the SAFE
range.
CAUTION!
Overfilling or underfilling the crankcase will cause
aeration or loss of oil pressure. This could damage
your engine.
3.0L Diesel Engine Only
Before checking the engine oil level, turn the engine off
and wait 15 minutes to allow for the oil to return to the oil
pan.
Change Engine Oil
Refer to the “Maintenance Schedule” in Section 8 for
proper maintenance intervals.
414 MAINTAINING YOUR VEHICLE

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
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To minimize the possibility of catalytic converter dam-
age:
•Do not shut off the engine or interrupt the ignition,
when the transmission is in gear and the vehicle is in
motion.
•Do not try to start the engine by pushing or towing the
vehicle.
•Do not idle the engine with any spark plug wires
disconnected or removed, such as when diagnostic
testing, or for prolonged periods during very rough
idle or malfunctioning operating conditions.
Cooling System
WARNING!
You or others can be badly burned by hot engine
coolant (antifreeze) or steam from your radiator. If
you see or hear steam coming from under the hood,
do not open the hood until the radiator has had time
to cool. Never try to open a cooling system pressure
cap when the radiator or coolant bottle is hot.
Engine Coolant Checks
Check the engine coolant (antifreeze) protection every
12 months (before the onset of freezing weather, where
applicable). If the engine coolant (antifreeze) is dirty or
rusty in appearance, the system should be drained,
flushed and refilled with fresh engine coolant (anti-
freeze). Check the front of the A/C condenser for any
424 MAINTAINING YOUR VEHICLE