2004 JEEP WRANGLER catalytic converter

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

It is even more important to look for gasoline without
MMT in Canada because MMT can be used at levels
higher than allowed in the United States. MMT is pro-
hibited in Federal and California reformulated gasoline.
Sulfur In Gasoline
If you live in the northeast United States, your vehicle
may have been designed to meet California low emission
standards with clean burning, low sulfur, California
gasoline. Gasoline sold outside of California is permitted
to have higher sulfur levels which may affect the perfor-
mance of the vehicle's catalytic converter. This may cause
the ªMalfunction Indicator Lightº to illuminate.
Illumination of this light while operating on high sulfur
gasoline does not necessarily mean your emission control
system is malfunctioning. The manufacturer recom-
mends that you try a different brand of unleaded gaso-
line having lower sulfur to determine if the problem is
fuel related prior to returning your vehicle to an autho-
rized dealer for service.
CAUTION!
If the ªMalfunction Indicator Lightº is flashing,
immediate service is required. See ªOnboard Diag-
nostic Systemº in Section 7 of this manual.
Materials Added To Fuel
All gasoline sold in the United States is required to
contain effective detergent additives. Use of additional
detergents or other additives is not needed under normal
conditions.
STARTING AND OPERATING 199
5

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
7

Inspect the drive belt for evidence of cuts, cracks, or
glazing and replace them if there is any sign of damage
which could result in belt failure. If adjustment is re-
quired, adjust the belts according to the specifications
and procedures shown in the Service Manual.
Special tools are required to properly measure tension
and to restore belt tension to factory specifications. Also,
check belt routing to make sure there is no interference
between the belts and other engine components.
Spark Plugs
Spark plugs must fire properly to assure engine perfor-
mance and emission control. New plugs should be in-
stalled at the mileage specified in the appropriate main-
tenance chart. The entire set should be replaced if there is
any malfunction due to a faulty spark plug.
Refer to the ªVehicle Emission Control Informationº label
in the engine compartment for spark plug information.
Catalytic Converter
The catalytic converter requires the use of unleaded fuel
only. Leaded gasoline will destroy the effectiveness of the
converter as an emission control device.
Under normal operating conditions, the catalytic con-
verter will not require maintenance. However, it is im-
portant to keep the engine properly tuned to assure
proper catalyst operation and prevent possible catalyst
damage.
CAUTION!
Damage to the catalytic converter can result if your
vehicle is not kept in proper operating condition. In
the event of engine malfunction, particularly involv-
ing engine misfire or other apparent loss of perfor-
mance, have your vehicle serviced promptly. Contin-
ued operation of your vehicle with a severe
malfunction could cause the converter to overheat,
resulting in possible damage to the converter and
vehicle.
232 MAINTAINING YOUR VEHICLE

WARNING!
A hot exhaust system can start a fire if you park over
materials that can burn. Such materials might be
grass or leaves coming into contact with your ex-
haust system. Do not park or operate your vehicle in
areas where your exhaust system can contact any-
thing that can burn.
In unusual situations involving grossly malfunctioning
engine operation, a scorching odor may suggest severe
and abnormal catalyst overheating. If this occurs, stop
the vehicle, turn off the engine and allow it to cool.
Service, including a tune up to manufacturer's specifica-
tions, should be obtained immediately.
To minimize the possibility of catalytic converter dam-
age:
²Do not shut off the engine or interrupt the ignition
when the transmission is in gear and the vehicle is in
motion.
²Do not try to start the engine by pushing or towing the
vehicle.
²Do not idle the engine with any spark plug wires
disconnected or removed, such as when diagnostic
testing.
²Do not idle the engine for prolonged periods during
very rough idle or malfunctioning operating condi-
tions.
²Do not allow vehicle to run out of fuel.
NOTE:Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
Engine Timing Belt Ð 2.4L Engine
Replace the engine timing belt at the intervals described
in the appropriate maintenance schedule.
Ignition Wiring System Ð 2.4L Engine
Replace the ignition cables at the intervals described in
the appropriate maintenance schedule.
MAINTAINING YOUR VEHICLE 233
7

Hoses.............................. 243
Master Cylinder...................... 244
Parking............................ 175
Warning Light....................... 119
Brakes............................... 177
Brake/Transmission Interlock.............. 166
Break-In Recommendations, New Vehicle...... 39
Bulb Replacement...................... 257
Calibration, Compass..................... 47
Capacities, Fluid....................... 258
Caps, Filler
Fuel............................... 200
Power Steering....................... 236
Car Washes........................... 249
Carpeting............................. 252
Cassette Tape and Player Maintenance....... 148
Cassette Tape Player.........126,130,132,140,142
Catalytic Converter..................... 232
Caution, Exhaust Gas..................... 40
CD Changer........................133,138
CD Player......................128,135,137
CD Player Maintenance.................. 149Cellular Phone......................... 149
Chains, Tire........................... 196
Changing A Flat Tire.................... 213
Chart, Tire Sizing....................... 185
Check Engine Light..................... 118
Child Restraint.....................29,33,36
Child Restraint Tether Anchors............. 33
Cigar Lighter........................... 62
Climate Control........................ 149
Clock................................ 120
Clutch Interlocking Ignition System......160,165
Compact Disc Maintenance............... 149
Compact Disc Player.................... 140
Compass.............................. 46
Compass Calibration..................... 47
Compass Variance....................... 48
Console............................... 65
Console, Floor.......................... 65
Contract, Service....................... 282
Converter, Catalytic..................... 232
Cooling System........................ 239
Adding Coolant (Antifreeze)............. 241
Coolant Capacity..................... 258
INDEX 289
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