2008 JEEP GRAND CHEROKEE check engine

of reasons, including the installation of replacement or
alternate tires or wheels on the vehicle that prevent the
TPMS from functioning properly. Always check the
TPMS malfunction telltale after replacing one or more
tires or wheels on your vehicle to ensure that the replace-
ment or alternate tires and wheels allow the TPMS to
continue to function properly.CAUTION!
The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures and
warning have been established for the tire size
equipped on your vehicle. Undesirable system opera-
tion or sensor damage may result when using re-
placement equipment that is not of the same size,
type, and/or style. After-market 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.
13. Temperature Gauge
The temperature gauge shows engine coolant tempera-
ture. Any reading within the normal range indicates that
the engine cooling system is operating satisfactorily.
178 UNDERSTANDING YOUR INSTRUMENT PANEL

15. Electronic Stability Program (ESP) Warning
Light/Brake Assist System (BAS) Warning Light Ð If
Equipped
The ESP/BAS warning light in the instrument
cluster comes on when the ignition switch is
turned to the ªONº position. The light should
go out with the engine running. If the ESP/
BAS warning light comes on continuously with the
engine running, a malfunction has been detected in either
the ESP or the BAS system. If this light stays illuminated,
have the ESP and BAS checked at your authorized dealer
as soon as possible.
16. Seat Belt Reminder Light
When the ignition switch is first turned ON, this
light will turn on for 5 to 8 seconds as a bulb check.
During the bulb check, if the driver's seat belt is
unbuckled, a chime will sound. After the bulb check or
when driving, if the driver or front passenger seat belt
remains unbuckled, the Seat Belt Warning Light will flashor remain on continuously. Refer to9Occupant Restraints
Ð Enhanced Driver Seat Belt Reminder System
(BeltAlert)9in Section 2 for more information.
17. Cruise Indicator Light
This indicator lights when the speed control
system is turned ON.
18. Odometer
The odometer shows the total distance the vehicle has
been driven.
U.S. federal regulations require that upon transfer of
vehicle ownership, the seller certify to the purchaser the
correct mileage that the vehicle has been driven. There-
fore, if the odometer reading is changed during repair or
replacement, be sure to keep a record of the reading
before and after the service so that the correct mileage can
be determined.
180 UNDERSTANDING YOUR INSTRUMENT PANEL

19. Transmission Range Indicator
This display indicator shows the automatic transmission
gear selection.
20. Fuel Gauge
The pointer shows the level of fuel in the fuel tank when
the ignition switch is in the ON position.
21. Electronic Throttle Control (ETC) Warning Light
This light informs you of a problem with the
Electronic Throttle Control system. If a problem
is detected the light will come on while the
engine is running. Cycle the ignition key when
the vehicle has completely stopped and the gear selector
is placed in the P (Park) position. The light should turn
off. If the light remains lit with the engine running your
vehicle will usually be drivable, however, see your dealer
for service as soon as possible. If the light is flashing
when the engine is running, immediate service is re-
quired and you may experience reduced performance, anelevated/rough idle or engine stall and your vehicle may
require towing. The light will come on when the ignition
is first turned on and remain on briefly as a bulb check.
If the light does not come on during starting, have the
system checked by an authorized dealer.
22. Front Fog Light Indicator LightÐ If Equipped
This light shows the front fog lights are ON.
23. Voltage Warning Light
This light monitors the electrical system voltage.
The light should turn on momentarily as the
engine is started. If the light stays on or turns on while
driving, it indicates a problem with the charging system.
Immediate service should be obtained.
24. Low Fuel Warning Light
When the fuel level reaches approximately 2.3 U.S.
Gallons (8.7 Liters) this light will come on and
remain on until fuel is added. The Low Fuel
UNDERSTANDING YOUR INSTRUMENT PANEL 181
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WARNING!
Do not connect trailer brakes to your vehicle's hy-
draulic brake lines. It can overload your brake sys-
tem and cause it to fail. You might not have brakes
when you need them and could have an accident.
Towing any trailer will increase your stopping dis-
tance. When towing you should allow for additional
space between your vehicle and the vehicle in front
of you. Failure to do so could result in an accident.
Towing Tips
Before setting out on a trip, practice turning, stopping
and backing the trailer in an area away from heavy
traffic.
Towing Tips Ð Automatic Transmission
The ªDº range can be selected when towing. However, if
frequent shifting occurs while in this range, the ª3º range
should be selected.
NOTE:Using the ª3º range while operating the vehicle
under heavy operating conditions will improve perfor-
mance and extend transmission life by reducing exces-
sive shifting and heat build up. This action will also
provide better engine braking.
The automatic transmission fluid and filter should be
changed if you REGULARLY tow a trailer for more than
45 minutes of continuous operation. See Schedule ªBº in
section 8 of this manual for transmission fluid change
intervals.
NOTE:Check the automatic transmission fluid level
before towing.
STARTING AND OPERATING 295
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MAINTAINING YOUR VEHICLE
CONTENTS
mEngine Compartment ± 6.1L...............306
mOnboard Diagnostic System Ð OBD II........307
NLoose Fuel Filler Cap Message............308
mEmissions Inspection And Maintenance
Programs............................308
mReplacement Parts......................310
mDealer Service.........................310
mMaintenance Procedures..................311
NEngine Oil..........................311NEngine Oil Filter......................315
NDrive Belts Ð Check Condition And
Tensioner...........................315
NSpark Plugs.........................316
NEngine Air Cleaner Filter................316
NFuel Filter..........................317
NCatalytic Converter....................317
NMaintenance-Free Battery................318
NAir Conditioner Maintenance.............319
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For states which have an I/M (Inspection and
Maintenance) requirement, this check verifies the
following: the MIL (Malfunction Indicator Lamp)
is functioning and is not on when the engine is running,
and that the OBD (On Board Diagnostic) system is ready
for testing.
Normally, the OBD system will be ready. The OBD
system maynotbe ready if your vehicle was recently
serviced, if you recently had a dead battery, or a battery
replacement. If the OBD system should be determined
not ready for the I/M test, your vehicle may fail the test.
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 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 your 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 off the
ignition key or start the engine. This means that your
vehicle's OBD system isnot readyand you shouldnot
proceed to the I/M station.
MAINTAINING YOUR VEHICLE 309
7

b. The MIL will not flash at all and will remain fully
illuminated until you turn off the ignition key or start
the engine. This means that your vehicle's OBD system
isreadyand you can proceed to the I/M station.
If your OBD 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
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 system is
ready or not ready, if the MIL symbol is illuminated
during normal vehicle operation, you should have your
vehicle serviced before going to the I/M station. The I/M
station can fail your vehicle because the MIL symbol is on
with the engine running.REPLACEMENT PARTS
Use of genuine Mopartparts for normal/scheduled
maintenance and repairs is highly recommended to in-
sure the designed performance. Damage or failures
caused by the use of non-Mopartparts for maintenance
and repairs will not be covered by the manufacturer's
warranty.
DEALER SERVICE
Your dealer has the qualified service personnel, special
tools and equipment to perform all service operations in
an expert manner. Service Manuals are available which
include detailed service information for your vehicle.
Refer to these manuals before attempting any procedure
yourself.
NOTE:Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
310 MAINTAINING YOUR VEHICLE

WARNING!
You can be badly injured working on or around a
motor vehicle. Do only that service work for which
you have the knowledge and the proper equipment.
If you have any doubt about your ability to perform
a service job, take your vehicle to a competent
mechanic.
MAINTENANCE PROCEDURES
The pages that follow contain therequiredmaintenance
services determined by the engineers who designed your
vehicle.
Besides the maintenance items for which there are fixed
maintenance intervals, there are other items that should
operate satisfactorily without periodic maintenance.
However, if a malfunction of these items does occur, itcould 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 5
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 ªSAFEº range. Adding one quart of oil
when the reading is at the bottom of the ªSAFEº range
will result in an oil level at the top of the ªSAFEº range
on these engines.
MAINTAINING YOUR VEHICLE 311
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