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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
560 MAINTAINING YOUR VEHICLE
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(EVIC)” or “Driver Information Display (DID)” in “Un-
derstanding Your Instrument Panel” for further informa-
tion. Tighten the fuel filler cap properly and push 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 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.
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.7
MAINTAINING YOUR VEHICLE 561
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CAUTION!(Continued)
•Your vehicle has been built with improved fluids
that protect the performance and durability of your
vehicle and also allow extended maintenance inter-
vals. Do not use chemical flushes in these compo-
nents as the chemicals can damage your engine,
transmission, or air conditioning. Such damage is
not covered by the New Vehicle Limited Warranty.
If a flush is needed because of component malfunc-
tion, use only the specified fluid for the flushing
procedure.
Engine Oil
Checking Oil Level
To assure proper lubrication of your vehicle’s engine, the
engine oil must be maintained at the correct level. Check
the oil level at regular intervals, such as every fuel stop. The best time to check the engine oil level is about five
minutes after a fully warmed up engine is shut off.
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.
CAUTION!
Overfilling or underfilling the crankcase will cause
oil aeration or loss of oil pressure. This could damage
your engine.
564 MAINTAINING YOUR VEHICLE
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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. 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.
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.
582 MAINTAINING YOUR VEHICLE
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Cavity Cartridge Fuse Micro FuseDescription
F01 80 Amp Black –Rad Fan Control Module – If equipped
F03 60 Amp Yellow –Rad Fan – If Equipped
F05 40 Amp Green –Compressor for Air Suspension – If Equipped
F06 40 Amp Green –Antilock Brakes/Electronic Stability Control
Pump
F07 40 Amp Green –Starter Solenoid
F08 20 Amp Blue (1500 LD/Cummins Die-sel) –
Emissions Diesel – If Equipped
F09 40 Amp Green (Special ServicesVehicle & Cum- mins Diesel)
30 Amp Pink (1500 LD Diesel) –
Diesel Fuel Heater – If Equipped
F10 40 Amp Green –Body Controller / Exterior Lighting #2
7
MAINTAINING YOUR VEHICLE 605
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Cavity Cartridge Fuse Micro FuseDescription
F37 30 Amp Pink –Cummins Diesel Fuel Heater #2 – If Equipped
F38 30 Amp Pink –Power Inverter 115V AC – If Equipped
F39 20 Amp Blue –Power Outlet – Special Services Only
F41 –10 Amp Red Active Grill Shutter – If Equipped
F42 –20 Amp Yellow Horn
F44 –10 Amp Red Diagnostic Port
F46 –10 Amp Red Upfitter – If Equipped
F49 –10 Amp Red Instrument Panel Cluster
F50 –20 Amp Yellow Air Suspension Control Module – If Equipped
F51 –10 Amp Red Ignition Node Module / Keyless Ignition
F52 –5 Amp Tan Battery Sensor
F53 –20 Amp Yellow Trailer Tow – Left Turn/Stop Lights
F54 –20 Amp Yellow Adjustable Pedals
F56 –15 Amp Blue Additional Diesel Content – If Equipped
F57 –20 Amp Yellow Transmission
608 MAINTAINING YOUR VEHICLE
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Cavity Cartridge Fuse Micro FuseDescription
F58 –20 Amp Yellow Spare Fuse
F59 –10 Amp Red SCR Relay – If Equipped
F60 –15 Amp Blue Underhood Lamp
F61 –10 Amp Red (1500
LD Diesel & Cum- mins Diesel) PM Sensor – If Equipped
F62 –10 Amp Red Air Conditioning Clutch
F63 –20 Amp Yellow Ignition Coils (Gas), Urea Heater (Cummins Die-
sel)
F64 –25 Amp Clear Fuel Injectors / Powertrain
F65 –10 Amp Red USB interface
F66 –10 Amp Red Sunroof / Passenger Window Switches / Rain
Sensor
F67 –10 Amp Red CD / DVD / Bluetooth Hands-free Module – If
Equipped
7
MAINTAINING YOUR VEHICLE 609
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Cavity Cartridge Fuse Micro FuseDescription
F69 –15 Amp Blue Mod SCR 12V (Cummins Diesel) – If Equipped
F70 –30 Amp Green Fuel Pump Motor
F71 –25 Amp Clear Amplifier
F72 –10 Amp Red PCM – If Equipped
F73 –20 Amp Yellow Fuel Transfer Pump (HD Only) – If Equipped
F74 –20 Amp Yellow
(Gas Engine & 1500 LD Diesel) Brake Vacuum Pump Gas/Diesel – If Equipped
F75 –10 Amp Red Coolant Temperature Valve Actuator
F76 –10 Amp Red Antilock Brakes / Electronic Stability Control
F77 –10 Amp Red Drivetrain Control Module/Front Axle Disconnect
Module
F78 –10 Amp Red Engine Control Module / Electric Power Steering
F79 –15 Amp Blue Clearance Lights
F80 –10 Amp Red Universal Garage Door Opener / Compass
610 MAINTAINING YOUR VEHICLE