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CAUTION!
•Damage to the fuel system or emissions control
system could result from using an improper fuel
tank filler tube cap.
•A poorly fitting fuel filler cap could let impurities
into the fuel system.
•A poorly fitting fuel filler cap may cause the
“Malfunction Indicator Light (MIL)” to turn on.
•To avoid fuel spillage and overfilling, do not “top
off” the fuel tank after filling. When the fuel
nozzle “clicks” or shuts off, the fuel tank is full.
WARNING!
•Never have any smoking materials lit in or near the
vehicle when the gas cap is removed or the tank is
being filled.
(Continued)
WARNING!(Continued)
•Never add fuel to the vehicle when the engine is
running.
•A fire may result if gasoline is pumped into a
portable container that is inside of a vehicle. You
could be burned. Always place gas containers on
the ground while filling.
NOTE:
•Tighten the gas cap until you hear a “clicking” sound.
This is an indication that the gas cap is tightened
properly. The MIL in the instrument cluster may turn
on if the gas cap is not secured properly. Make sure
that the gas cap is tightened each time the vehicle is
refueled.
•When the fuel nozzle “clicks” or shuts off, the fuel tank
is full.
644 STARTING AND OPERATING
Page 747 of 871
MAINTAINING YOUR VEHICLE
CONTENTS
!ENGINE COMPARTMENT — 3.6L..........748
!ENGINE COMPARTMENT — 5.7L..........749
!ENGINE COMPARTMENT — 6.4L..........750
!ONBOARD DIAGNOSTIC SYSTEM (OBD II) . . .751
▫Loose Fuel Filler Cap Message............751
!EMISSIONS INSPECTION AND MAINTENANCE
PROGRAMS..........................752
!REPLACEMENT PARTS..................753
!DEALER SERVICE......................754
!MAINTENANCE PROCEDURES...........754
▫Engine Oil..........................755
▫Engine Oil Filter......................758
▫Engine Air Cleaner Filter................759
▫Accessory Drive Belt Inspection...........762
▫Maintenance-Free Battery...............764
▫Air Conditioner Maintenance.............765
▫Front Driveshaft Lubrication — 2500/3500
(Four-Wheel Drive Models Only)..........766
▫Body Lubrication.....................767
▫Windshield Wiper Blades...............767
7
Page 753 of 871

ONBOARD DIAGNOSTIC SYSTEM (OBD II)
Your vehicle is equipped with a sophisticated onboard
diagnostic system called OBD II. This system monitors
the performance of the emissions, engine, and automatic
transmission control systems. When these systems are
operating properly, your vehicle will provide excellent
performance and fuel economy, as well as engine emis-
sions well within current government regulations.
If any of these systems require service, the OBD II system
will turn on the “Malfunction Indicator Light (MIL).” It
will also store diagnostic codes and other information to
assist your service technician in making repairs. Al-
though your vehicle will usually be drivable and not
need towing, see your authorized dealer for service as
soon as possible.
CAUTION!
•Prolonged driving with the MIL on could cause
further damage to the emission control system. It
could also affect fuel economy and driveability.
The vehicle must be serviced before any emissions
tests can be performed.
•If the MIL is flashing, while the engine is running,
severe catalytic converter damage and power loss
will soon occur. Immediate service is required.
Loose Fuel Filler Cap Message
If the vehicle diagnostic system determines
that the fuel filler cap is loose, improperly
installed, or damaged, a loose gascap indicator
will display in the EVIC/DID telltale display
area. Refer to “Electronic Vehicle Information Center
7
MAINTAINING YOUR VEHICLE 751
Page 754 of 871

(EVIC)” or “Driver Information Display (DID)” in “Un-
derstanding Your Instrument Panel” for further informa-
tion. Tighten the fuel filler cap properly and press the
SELECT button to turn off the message. If the problem
continues, the message will appear the next time the
vehicle is started.
A loose, improperly installed, or damaged fuel filler cap
may also turn on the Malfunction Indicator Light (MIL).
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 maynotbe 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.
Your vehicle has a simple ignition actuated test, which
you can use prior to going to the test station. To check if
your vehicle’s OBD II system is ready, you must do the
following:
1. Cycle the ignition switch to the ON position, but do
not crank or start the engine.
NOTE:If you crank or start the engine, you will have to
start this test over.
2. As soon as you cycle the ignition switch to the ON
position, you will see the MIL symbol come on as part
of a normal bulb check.
752 MAINTAINING YOUR VEHICLE
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DEALER SERVICE
Your authorized dealer has the qualified service person-
nel, 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 Service Manuals before
attempting any procedure yourself.
NOTE:Intentional tampering with emissions control
systems may void your warranty and could result in civil
penalties being assessed against you.
WARNING!
You can be badly injured working on or around a
motor vehicle. Only do 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 me-
chanic.
MAINTENANCE PROCEDURES
The pages that follow contain therequiredmaintenance
services determined by the engineers who designed your
vehicle.
Besides those maintenance items specified in the fixed
“Maintenance Schedule”, there are other components
which may require servicing or replacement in the future.
CAUTION!
•Failure to properly maintain your vehicle or per-
form repairs and service when necessary could
result in more costly repairs, damage to other
components or negatively impact vehicle perfor-
mance. Immediately have potential malfunctions
examined by an authorized dealer or qualified
repair center.
(Continued)
754 MAINTAINING YOUR VEHICLE
Page 775 of 871

WARNING!
•Exhaust gases can injure or kill. They contain
carbon monoxide (CO), which is colorless and
odorless. Breathing it can make you unconscious
and can eventually poison you. To avoid breathing
CO, refer to “Safety Tips/Exhaust Gas” in “Things
To Know Before Starting Your Vehicle” for further
information.
•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
exhaust system. Do not park or operate your ve-
hicle in areas where your exhaust system can con-
tact anything that can burn.
CAUTION!
•The catalytic converter requires the use of un-
leaded fuel only. Leaded gasoline will destroy the
effectiveness of the catalyst as an emissions control
device and may seriously reduce engine perfor-
mance and cause serious damage to the engine.
•Damage to the catalytic converter can result if your
vehicle is not kept in proper operating condition.
In the event of engine malfunction, particularly
involving engine misfire or other apparent loss of
performance, have your vehicle serviced promptly.
Continued operation of your vehicle with a severe
malfunction could cause the converter to overheat,
resulting in possible damage to the converter and
vehicle.
7
MAINTAINING YOUR VEHICLE 773
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Under normal operating conditions, the catalytic converter
will not require maintenance. However, it is important to
keep the engine properly tuned to assure proper catalyst
operation and prevent possible catalyst damage.
NOTE:Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
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:
•Do not shut off the engine or interrupt the ignition,
when the transmission is in gear and the vehicle is in
motion.
•Do not try to start the engine by pushing or towing the
vehicle.
•Do not idle the engine with any spark plug wires
disconnected or removed, such as when diagnostic
testing, or for prolonged periods during very rough
idle or malfunctioning operating conditions.
Cooling System
WARNING!
You or others can be badly burned by hot engine
coolant (antifreeze) or steam from your radiator. If
you see or hear steam coming from under the hood,
do not open the hood until the radiator has had time
to cool. Never try to open a cooling system pressure
cap when the radiator is hot.
774 MAINTAINING YOUR VEHICLE
Page 801 of 871
Cavity Cartridge Fuse Micro FuseDescription
F0180 Amp BlackRad Fan Control Module – If equipped
F03 60 Amp YellowRad Fan – If Equipped
F0540 Amp GreenCompressor for Air Suspension – If Equipped
F0640 Amp GreenAntilock Brakes/Electronic Stability Control
Pump
F0740 Amp GreenStarter Solenoid
F08 20 Amp Blue (1500
LD Diesel)
30 Amp Pink
(Cummins Diesel)
Emissions Diesel – If Equipped
F0940 Amp Green
(Special Services
Vehicle & Cummins
Diesel)
30 Amp Pink (1500
LD Diesel)
Diesel Fuel Heater – If Equipped7
MAINTAINING YOUR VEHICLE 799