2007 JEEP WRANGLER check engine

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 gear
selector is placed in the P (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 dealer for service as soon as possible.
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 remainon briefly as a bulb check. If the light does not come on
during starting, have the system checked by an 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.
210 UNDERSTANDING YOUR INSTRUMENT PANEL

After initial calibration, the compass will continue to
automatically update this calibration whenever the ve-
hicle is in motion.
Manual Compass Calibration
NOTE: Before attempting a manual compass calibra-
tion, the engine must be running and the transmission
in the P (Park) position (if equipped).
Compass calibration can also be requested. To manually
calibrate the compass, you must first enter the variance
mode. Press the and hold the left button (located on the
instrument cluster) for approximately 10 seconds to enter
the variance mode, and release the button when the VAR
symbol appears. The current variance value will also be
displayed. Once in the variance mode, it is necessary to
release the button, and then press and hold it again
(approximately 10 seconds) until CAL is displayed (solid
not blinking). Manual compass calibration has been
initiated. Drive the vehicle slowly in one or more circlesunder 5 mph (8 km/h) in an area free from large metal
objects until the CAL symbol is extinguished.
When the CAL symbol no longer is displayed, the
compass is calibrated and should display correct head-
ings. Verify proper calibration by checking North (N),
South (S), East (E), and West (W). If the compass does not
appear accurate, repeat the calibration procedure in an-
other area.
Compass Variance
Variance is the difference between magnetic North and
geographic North. For proper compass function, the
correct variance zone must be set.
Setting the Compass Variance
Refer to the variance map for the correct compass vari-
ance zone. To check the variance zone, the ignition must
be on. Press and hold the left button (located on the
instrument cluster) for approximately 10 seconds to enter
the variance mode and release the button when the VAR
214 UNDERSTANDING YOUR INSTRUMENT PANEL

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 B” in
section 8 of this manual for transmission fluid change
intervals.
NOTE:Check the automatic transmission fluid level
before towing.
Towing Tips — O/D Off (If Equipped)
To reduce potential for automatic transmission overheat-
ing, turn the “O/D OFF” feature OFF 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.
Towing Tips — Cooling System
To reduce potential for engine and transmission over-
heating, take the following actions:
Highway Driving
Reduce speed.
Air Conditioning
Turn off temporarily.
refer to Cooling System Operating information in the
Maintenance section of this manual for more informa-
tion.
STARTING AND OPERATING 345
5

MAINTAINING YOUR VEHICLE
CONTENTS
Engine Compartment – 3.8L...............364
Onboard Diagnostic System — OBD II........365
▫Loose Fuel Filler Cap Message............366
Emissions Inspection And Maintenance
Programs............................366
Replacement Parts......................368
Dealer Service.........................368
Maintenance Procedures..................369
▫Engine Oil..........................369▫Drive Belts — Check Condition And Tension . . 372
▫Spark Plugs.........................373
▫Catalytic Converter....................373
▫Crankcase Emission Control System........375
▫Fuel Filter..........................375
▫Engine Air Cleaner Filter................375
▫Maintenance-Free Battery................376
▫Air Conditioner Maintenance.............376
▫Power Steering Fluid Check..............377
7

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 loose fuel filler cap message
will be displayed in the instrument cluster. Tighten the
gas cap until aclickingsound 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 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.
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, which have an I/M (Inspection and
Maintenance) requirement, this check verifies the
following: the MIL (Malfunction Indicator Light)
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.
366 MAINTAINING YOUR VEHICLE

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 theignition key or start the engine. This means that your
vehicle’s OBD system isnot readyand you shouldnot
proceed to the I/M station.
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
MAINTAINING YOUR VEHICLE 367
7

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, 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 lubrication of your vehicle’s engine, the
engine oil must be maintained at the correct level. The
best time to check the engine oil level is about 5 minutes
after a fully warmed up 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. Always
maintain the oil level within the SAFE zone on the
dipstick. Adding one quart of oil when the reading is at
the bottom of the SAFE zone will result in a reading at the
top of the safe zone on these engines.
MAINTAINING YOUR VEHICLE 369
7

CAUTION!
Overfilling or underfilling the crankcase will cause
aeration or loss of oil pressure. This could damage
your engine.
Change Engine Oil
Road conditions as well as your kind of driving affect the
interval at which your oil should be changed. Check the
following to determine if any apply to you:
•Day or night temperatures are below 32°F (0°C)
•Stop and go driving
•Extensive engine idling
•Driving in dusty conditions
•Short trip driving of less than 10 miles (16.2 km)
•More than 50% of your driving is at sustained high
speeds during hot weather, above 90°F (32°C)
•Taxi, Police, or delivery service (commercial service)
•Trailer towing
•Off-road or desert driving
•If equipped for and operating with E–85 (ethanol) fuel
IfANYof these apply to you, then change your engine oil
at every interval shown in schedule “B” of the “Mainte-
nance Schedules” section of this manual.
If none of these apply to you, then change your engine oil
at every interval shown on schedule “A” of the “Main-
tenance Schedules” section of this manual
NOTE:Under no circumstances should oil change in-
tervals exceed 6,000 miles (10 000 km) or 6 months
whichever comes first.
370 MAINTAINING YOUR VEHICLE