2004 JEEP WRANGLER check engine

Key-In-Ignition Reminder
Opening the driver's door when the key is in the ignition,
sounds a signal to remind you to remove the key.
CAUTION!
Always remove the key from the ignition, and lock
all doors when leaving the vehicle unattended.
SENTRY KEY IMMOBILIZER SYSTEM Ð IF
EQUIPPED
The Sentry Key Immobilizer System (SKIS) prevents
unauthorized operation of the vehicle by disabling the
engine. The system will shut the engine down after 2
seconds of running if an invalid key is used to start the
vehicle. This system utilizes ignition keys which have an
electronic chip (transponder) embedded into them. Only
keys that have been programmed to the vehicle can be
used to start and operate the vehicle for longer than the
2 second validation time period.
The Sentry Key Immobilizer System does not need to be
armed or activated. Operation of the system is automaticregardless of whether or not the vehicle is locked or
unlocked. During normal operation, the SKIS indicator
light will come on for 3 seconds immediately after the
ignition switch is turned on for a bulb check. Afterwards,
if the bulb remains on, this indicates a malfunction in the
electronics. If the bulb begins to flash immediately after
the ignition switch is turned on, this indicates that an
invalid key is being used to start the vehicle. Both of
these conditions will result in the engine being shut
down after 2 seconds of running. Keep in mind that a key
which has not been programmed is also considered an
invalid key even if it is cut to fit the ignition for that
vehicle.
If the SKIS indicator light comes on during normal
vehicle operation (it has been running for longer than 10
seconds) a fault has been detected in the electronics and
the vehicle should be serviced as soon as possible.
NOTE:
²
The Sentry Key Immobilizer System is not compatible
with remote starting systems. Use of these systems
may result in vehicle starting problems and loss of
security protection.
12 THINGS TO KNOW BEFORE STARTING YOUR VEHICLE

Front Fog Lights Ð If Equipped
The front fog light switch is in the multi-function
control lever. To activate the front fog lights, turn
on the parking or low beam headlights and pull
out the end of the lever.
NOTE:The fog lights will only operate with the park-
ing lights or the headlights on low beam. Selecting high
beam headlights will turn off the fog lights.
Turn Signals
Move the multi-function control lever up or down and
the arrows on each side of the instrument cluster flash to
show proper operation of the front and rear turn signal
lights. You can signal a lane change by moving the lever
partially up or down without moving beyond the detent.
If either light remains on and does not flash, or there is a
very fast flash rate, check for a defective outside light
bulb. If an indicator fails to light when the lever is
moved, it would suggest that the fuse or indicator bulb is
defective.
NOTE:A tone will chime if the turn signals are left on
for more than 1 mile (2 km).
Daytime Running Lights Ð Canada Only
The headlights come on at a low intensity level after the
vehicle has been driven approximately 3 feet (1 meter).
They will turn off when the vehicle is turned off or when
the headlights are switched on.
WINDSHIELD WIPERS AND WASHERS
CAUTION!
In cold weather, always turn off the wiper switch
and allow the wipers to return to the park position
before turning off the engine. If the wiper switch is
left on and the wipers freeze to the windshield,
damage to the wiper motor may occur when the
vehicle is restarted.
Intermittent Wiper System
Use the intermittent wiper when weather conditions
make a single wiping cycle, with a variable pause be-
tween cycles, desirable. Move the lever to the DELAY
position, then select the delay interval by turning the end
58 UNDERSTANDING THE FEATURES OF YOUR VEHICLE

15. Coolant Temperature Gauge
Indicates engine coolant temperature. The red
zone to the far right indicates possible overheat-
ing. Seek authorized service immediately if the
gauge operates in the red zone. In U.S. vehicles,
temperature is indicated in degrees fahrenheit; in
Canadian vehicles in degrees centigrade.
16. Airbag Warning Light
This indicator lights and remains lit for 6 to
8 seconds when the ignition is first turned
on. If the light does not come on for 6 to 8
seconds, stays on or comes on while driving,
have the airbag system checked by an authorized
dealer.
17. Check Gauges Warning Light
This light monitors the engine coolant tem-
perature, engine oil pressure, and voltage
gauges. If it detects an extreme condition a
chime will sound and the light will come on. If the
light comes on, check the operation of these gauges for
a malfunction condition.18. 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 ªMalfunction Indicator
Lightº 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.
118 UNDERSTANDING YOUR INSTRUMENT PANEL

If the parking brake is applied and the vehicle is in
motion, the red BRAKE warning light will ªflashº and a
chime will sound.
The operation of the BRAKE warning light can be
checked by turning the ignition switch from the OFF
position to the ON position. The light should illuminate
for approximately two seconds. The light should then
turn off unless the parking brake is applied or a brake
fault is detected. If the light does not illuminate, have the
light inspected by an authorized dealer.
23. Low Fuel Warning Light
When the fuel level reaches approximately 2 U.S.
Gallons (7.6L) this light will come on and remain
on until fuel is added. The ªLow Fuel Warning
Lightº may turn on and off again, especially during
and after hard braking, accelerations, or turns. This
occurs due to the shifting of the fuel in the tank.
24. Fuel Cap Indicator
This symbol indicates the side of the vehicle
where the fuel cap is located.25. Fuel Gauge
The pointer shows the level of fuel in the fuel tank. When
the fuel gauge pointer initially moves to E, for your
safety, approximately 2 U.S. Gallons (7.6L) of fuel remain.
NOTE:When the ignition switch is turned to OFF, the
fuel gauge, voltmeter, oil pressure and temperature
gauges may not show accurate readings. When the
engine is not running, turn the ignition switch to ON to
obtain accurate readings.
ELECTRONIC DIGITAL CLOCK
The clock and radio each use the display panel built into
the radio. A digital readout shows the time in hours and
minutes whenever the ignition switch is in the ON or
ACC position and the time button is pressed.
When the ignition switch is in the OFF position, or when
the radio frequency is being displayed, time keeping is
accurately maintained.
120 UNDERSTANDING YOUR INSTRUMENT PANEL

CAUTION!
Use care when washing the inside of the rear win-
dow to prevent damage to heating elements. Use a
soft cloth and a mild washing solution, wiping
parallel to the heating elements. Also, keep all
objects a safe distance from the window to prevent
damaging the heating elements.
Rear Window Wiper/Washer
To utilize the rear wiper, press the switch to the
first detent. To activate the rear washer, depress the
switch to the second detent. The washer will
continue to spray as long as the switch is held. The switch
will return to the wiper mode when released. To turn the
rear wiper off, lift the bottom of the switch.
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 on the passenger side and
should be checked for fluid level at regular intervals. Fill
the reservoir with windshield washer solvent (not radia-
tor antifreeze) and operate the system for a few seconds
to flush out the residual water.
UNDERSTANDING YOUR INSTRUMENT PANEL 155
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WARNING!
To help avoid personal injury, follow these tips:
²Never reach through the steering wheel to operate
steering column controls. Injury to your hands or
loss of vehicle control may result.
²If the engine stalls or power assist fails due to a
malfunction, vehicle steering and braking will
require greater effort.
ANTI-LOCK BRAKE SYSTEM Ð IF EQUIPPED
The Anti-Lock Brake System is designed to aid the driver
in maintaining vehicle control under adverse braking
conditions. The system operates with a separate com-
puter to modulate hydraulic pressure to prevent wheel
lock-up and help avoid skidding on slippery surfaces.
All vehicle wheels and tires must be the same size and
type and tires must be properly inflated to produce
accurate signals for the computer.
WARNING!
Significant over or under-inflation of tires, or mixing
sizes of tires or wheels on the vehicle can lead to loss
of braking effectiveness.
The Anti-Lock Brake System conducts a low speed self-
test at about 12 mph (20 km/h). If for any reason, your
foot is on the brake when the vehicle reaches 12 mph (20
km/h), this check will be delayed until 25 mph (40
km/h).
The Anti-Lock Brake System pump motor runs during
the self-test and during an ABS stop to provide the
regulated hydraulic pressure. The motor pump makes a
low humming noise during operation, this is normal.
During off-road use, loss of traction can temporarily
defeat the system and cause the warning light to illumi-
nate. Turn the ignition OFF and ON again to restore
Anti-Lock Brake System function.
STARTING AND OPERATING 179
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Traction Downhill
Shift the transmission into a low gear and transfer case to
4L (Low) range. Let the vehicle go slowly down the hill
with all four wheels turning against engine compression
drag. This will permit you to control the vehicle speed
and direction.
After Driving Off-Road
Off-road operation puts more stress on your vehicle than
does most on-road driving. After driving off-road, it is
always a good idea to check for damage.
²Completely inspect the underbody of your vehicle.
Check tires, body structure, steering, suspension, and
exhaust system for damage.
²Check threaded fasteners for looseness, particularly on
the chassis, drivetrain components, steering, and sus-
pension. Retighten them, if required, and torque to the
values specified in the Service Manual.
²Check for accumulations of plants or brush. These
things could be a fire hazard, or they might hide
damage to fuel lines, brake hoses, axle pinion seals,
and propeller shafts.
²After extended operation in mud, sand, water, or
similar dirty conditions, have brake drums, brake
linings, and axle yokes inspected and cleaned as soon
as possible.
WARNING!
Abrasive material in any part of the brakes may
cause excessive wear or unpredictable braking. You
might not have full braking power when you need it
to prevent an accident. If you have been operating
your vehicle in dirty conditions, get your brakes
checked and cleaned as necessary.
²If you experience unusual vibration after driving in
mud, slush or similar conditions, check the wheels for
packed material. Packed foreign material can cause a
wheel imbalance and freeing the wheels will correct
the situation.
STARTING AND OPERATING 183
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MAINTAINING YOUR VEHICLE
CONTENTS
m2.4L Engine..........................223
m4.0L Engine..........................224
mOnboard Diagnostic System Ð OBD II......225
mEmissions Inspection And
Maintenance Programs
..................226
mReplacement Parts.....................227
mDealer Service........................227
mMaintenance Procedures.................228
NEngine Oil..........................228
NDrive Belts Ð Check Condition And Tension . . 231
NSpark Plugs.........................232
NCatalytic Converter....................232NEngine Timing Belt Ð 2.4L Engine.........233
NIgnition Wiring System Ð 2.4L Engine......233
NCrankcase Emission Control System........234
NFuel Filter..........................234
NEngine Air Cleaner Filter................234
NMaintenance-Free Battery................234
NAir Conditioner Maintenance.............235
NPower Steering Fluid Check..............236
NDriveline And Steering Component
Lubrication..........................237
NBody Lubrication.....................237
NWindshield Wiper Blades................237
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