check engine light JEEP WRANGLER 2008 JK / 3.G Owners Manual

the vehicle. The system will shut the engine off in two
seconds if someone uses an invalid key to try to start the
engine.
NOTE:A key that has not been programmed is also
considered an invalid key, even if it is cut to fit the
ignition switch lock cylinder for that vehicle.
During normal operation, after turning on the ignition
switch, the Vehicle Security Alarm Indicator Light will
turn on for three seconds for a bulb check. If the light
remains on after the bulb check, it indicates that there is
a problem with the electronics. In addition, if the light
begins to flash after the bulb check, it indicates that
someone used an invalid key to try to start the engine.
Either of these conditions will result in the engine being
shut off after two seconds.
If the Vehicle Security Alarm Indicator Light turns on
during normal vehicle operation (vehicle running for longer than 10 seconds), it indicates that there is a fault in
the electronics. Should this occur, have the vehicle ser-
viced as soon as possible.
NOTE:
•The Sentry Key
Immobilizer System is not compat-
ible with some aftermarket remote starting systems.
Use of these systems may result in vehicle starting
problems and loss of security protection.
•Exxon/Mobil Speedpass™, additional Sentry Keys,
or any other transponder-equipped components on
the same key chain will notcause a key-related
(transponder) fault unless the additional part is physi-
cally held against the ignition key being used when
starting the vehicle. Cell phones, pagers, or other RF
electronics will not cause interference with this system.
All of the keys provided with your new vehicle have
been programmed to the vehicle electronics.
THINGS TO KNOW BEFORE STARTING YOUR VEHICLE 15
2

•Do not inhale exhaust gases. They contain carbon
monoxide, a colorless and odorless gas which can kill.
Never run the engine in a closed area, such as a
garage, and never sit in a parked vehicle with the
engine running for an extended period. If the vehicle is
stopped in an open area with the engine running for
more than a short time, adjust the ventilation system
to force fresh, outside air into the vehicle.
•Guard against carbon monoxide with proper mainte-
nance. Have the exhaust system inspected every time
the vehicle is raised. Have any abnormal conditions
repaired promptly. Until repaired, drive with all side
windows fully open.
•Always run the climate control in panel or floor mode
when driving with any windows open, even if only
slightly, to help keep fresh air circulating inside the
vehicle. Otherwise poisonous gases could be drawn
into the vehicle.
•On hardtop models, keep the tailgate window closed
when driving your vehicle. On fabric top models, do
not drive with the rear window curtain up unless the
side curtains are also open. This will prevent carbon
monoxide and other poisonous exhaust gases from
entering the vehicle.
Safety Checks You Should Make Inside The
Vehicle
Seat Belts
Inspect the seat belt system periodically, checking for
cuts, frays and loose parts. Damaged parts must be
replaced immediately. Do not disassemble or modify the
system.
Seat belt assemblies must be replaced after an accident if
they have been damaged (bent retractor, torn webbing,
etc.). If there is any question regarding seat belt or
retractor condition, replace the seat belt.
76 THINGS TO KNOW BEFORE STARTING YOUR VEHICLE

If the rear wiper is operating when the ignition is turned
OFF, the wiper will automatically return to the “Park”
position. When the vehicle is restarted, the wiper will
resume function at whichever position the switch is set
at.
Adding Washer Fluid
The fluid reservoir for the windshield washers and the
rear window washer is shared. It is located in the front of
the engine compartment, and should be checked for fluid
level at regular intervals. Fill the reservoir with wind-
shield washer solvent (not radiator antifreeze) and oper-
ate the system for a few seconds to flush out the residual
water.
Rear Window Defroster — If Equipped
The pushbutton is located on
the bottom right side of the
blower control knob. Press
this button to turn on the rear
window defroster. An amber
light shows that the defroster
is on.
Windshield Wiper/Washer Switch
198 UNDERSTANDING THE FEATURES OF YOUR VEHICLE

7. Seat Belt Indicator LightA warning chime and an indicator light will alert
you to buckle the seat belts. When the belt is
buckled, the chime will stop, but the light will stay
on until it times out (about six seconds).
8. Turn Signal Indicator Lights The arrows will flash with the exterior turn signals
when the turn signal lever is operated. A tone will
chime if the turn signals are left on for more than 1 mi (2
km).
9. Oil Pressure Warning Light Shows low engine oil pressure. The light will come
on and remain on when the ignition switch is
turned from the OFF to the ON position, and the light
will turn off after the engine is started. If the bulb does
not come on, have the system checked by your autho-
rized dealer. If the warning light comes on and remains on while
driving, stop the vehicle and shut off the engine. DO
NOT OPERATE THE VEHICLE UNTIL THE CAUSE IS
CORRECTED. Also, a single chime will sound.
10. High Beam Indicator Light
This light shows that the headlights are on high
beam. Push the multifunction control lever away
from you to switch the headlights to high beam. Pull the
lever towards you to switch the headlights back to low
beam. If the driver’s door is open, and the headlights or
park lights are left on, the High Beam Indicator Light will
remain illuminated and a chime will sound.
11. Brake Warning Light After the ignition is turned on, this light illumi-
nates to indicate function check at vehicle start-
up. It also indicates if the parking brake is
applied. If the light stays on when the parking brake is
UNDERSTANDING YOUR INSTRUMENT PANEL 207
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2. Fully depress the accelerator pedal slowly three
times within 10 seconds.
3. Turn the ignition switch to the OFF/LOCK position.
NOTE: If the indicator message illuminates when you
start the vehicle, the oil change indicator system did not
reset. If necessary repeat this procedure.
25. Malfunction Indicator Light This light is a part of an Onboard Diagnostic
System called OBD II that monitors engine and
automatic transmission control systems. The light
will illuminate when the ignition is in the ON position
before engine start. If the bulb does not come on when
turning the key from OFF to ON, have the condition
checked promptly.
Certain conditions such as a loose or missing gas cap,
poor quality fuel, etc. may illuminate the light after
engine start. The vehicle should be serviced if the light stays on through several typical driving styles. In most
situations, the vehicle will drive normally and will not
require towing.
When the engine is running, the Malfunction Indicator
Light may flash to alert serious conditions that could lead
to immediate loss of power or severe catalytic converter
damage. The vehicle should be serviced as soon as
possible if this occurs.
26. Electronic Stability Program (ESP) Indicator
Light/Traction Control System (TCS) Indicator Light
This indicator light starts to flash as soon as the
tires lose traction and the ESP system becomes
active. The ESP/TCS Indicator Light also
flashes when TCS is active. If the ESP/TCS
Indicator Light begins to flash during acceleration, ease
up on the accelerator and apply as little throttle as
possible. Be sure to adapt your speed and driving to the
prevailing road conditions. The ESP/TCS Indicator Light
UNDERSTANDING YOUR INSTRUMENT PANEL 213
4

will flash anytime the ESP or TCS is active and helping to
improve vehicle stability. If the ESP/TCS Indicator Light
is on solid, the ESP system has been turned off by the
driver or a temporary condition exists that will not allow
full ESP function.
27. O/D (Overdrive) Off Indicator LightThis light will illuminate when the O/D OFF
button has been selected. The O/D OFF button is
located on the center console.
28. Sway Bar Indicator Light — If Equipped This light will illuminate when the front sway
bar is disconnected.
29. Electronic Stability Program (ESP)/Brake Assist
System (BAS) Warning Light The ESP/BAS Warning Light in the instrument
cluster comes on when the ignition switch is
turned to the ON 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. Refer to “Electronic Brake Control System” in
Section 3 for more information.
30. Electronic Throttle Control (ETC) Warning Light —
If Equipped
This light informs you of a problem with the
Electronic Throttle Control System. If a prob-
lem is detected while the engine is running, the
light will either stay on or flash depending on
the nature of the problem. Cycle the ignition key when
the vehicle is safely and completely stopped and the shift
lever is placed in the PARK position. The light should
turn off. If the light remains on with the engine running,
your vehicle will usually be drivable, however, see your
authorized dealer for service as soon as possible.
214 UNDERSTANDING YOUR INSTRUMENT PANEL

If the light continues to flash when the engine is running,
immediate service is required and you may experience
reduced performance, an elevated/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 your autho-
rized dealer.
31. Compass/Mini-Trip Computer Display — If
Equipped
When the appropriate conditions exist, this display
shows the Mini-Trip Computer messages. Refer to “Mini-
Trip Computer” later in this section.
32. Compass/Mini-Trip Computer Button—If Equipped
Press this button to switch between the different func-
tions.COMPASS AND TRIP COMPUTER — IF
EQUIPPED
This feature, located on the instrument cluster (speedom-
eter and tachometer), displays information on outside
temperature, compass direction, and trip information.
UNDERSTANDING YOUR INSTRUMENT PANEL 215
4

If using a manual transmission vehicle for trailer towing,
all starts must be in 1st gear to avoid excessive clutch
slippage.
Towing Tips — Automatic Transmission
The DRIVE range can be selected when towing. How-
ever, if frequent shifting occurs while in this range, the
OVERDRIVE range should be selected.
NOTE:Using “O/D OFF” 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. Refer to the “Main-
tenance Schedule” in Section 8 of this manual for trans-
mission fluid change intervals. NOTE:
Check the automatic transmission fluid level
before towing.
Towing Tips — O/D Off
To reduce potential for automatic transmission overheat-
ing, select the “O/D OFF” feature when driving in hilly
areas or shift the transmission to DRIVE position 2 on
more severe grades. Refer to “Transmission Shifting” in
this section.
Towing Tips — Electronic Speed Control (If
Equipped)

Don’t 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.
358 STARTING AND OPERATING

Loose Fuel Filler Cap Message
After fuel is added, the vehicle diagnostic system can
determine if the fuel filler cap is possibly loose, improp-
erly installed, or damaged. A “gASCAP” message will be
displayed in the odometer. Tighten the gas cap until a
clickingsound is heard. This is an indication that the
gas cap is properly tightened. Press the odometer reset
button to turn the message off. If the problem persists,
the message will appear the next time the vehicle is
started. This might indicate a damaged cap. If the prob-
lem is detected twice in a row, the system will turn on the
“Malfunction Indicator Light.” Resolving the problem
will turn the “Malfunction Indicator Light.” off.
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 may notbe 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.
380 MAINTAINING YOUR VEHICLE

CAUTION!
Be aware that if the fluid temperature is below 50° F
(10° C), it may not register on the dipstick. Do not add
fluid until the temperature is elevated enough to
produce an accurate reading.
7. Check for leaks. Release the parking brake.
NOTE: To prevent dirt and water from entering the
transmission after checking or replenishing fluid, make
certain that the dipstick cap is properly reseated. It is
normal for the dipstick cap to spring back slightly from
its fully seated positions, as long as its seal remains
engaged in the dipstick tube.
Special Additives
Automatic Transmission Fluid (ATF) is an engineered
product and its performance may be impaired by supple-
mental additives. Therefore, do not add any fluid addi-
tives to the transmission. The only exception to this
policy is the use of special dyes to aid in detecting fluid
leaks. In addition, avoid using transmission sealers as
they may adversely affect seals.
Hydraulic Clutch Fluid — Manual Transmission
The clutch hydraulic system is a sealed maintenance free
system. In the event of leakage or other malfunction, the
system must be replaced.
Manual Transmission
Selection of Lubricant
Use only manufacturer’s recommended manual trans-
mission fluid. Refer to Fluids, Lubricants, and Genuine
Parts in this section for the correct fluid type.
MAINTAINING YOUR VEHICLE 403
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