2003 GMC YUKON DENALI octane

Light On Steady - An emission control system
malfunction has been detected on your vehicle.
Dealer or qualified service center diagnosis
and service may be required.
If the Light is Flashing
The following may prevent more serious damage to
your vehicle:
Reducing vehicle speed.
Avoiding hard accelerations.
Avoiding steep uphill grades.
If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.
If the light stops flashing and remains on steady, see “If
the Light
Is On Steady” following.
If the light continues to flash, when
it is safe to do so,
stop the vehicle. Find a safe place to park your vehicle.
Turn the key
off, wait at least 10 seconds and restart
the engine. If the light remains on steady, see
“If
the Light Is On Steady” following. If the light is still
flashing, follow the previous steps, and drive the vehicle
to your dealer or qualified service center for service.
If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did
you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully install
the cap. See Filling
Your Tank on page 5-7. The
diagnostic system can determine
if the fuel cap has
been left
off or improperly installed. A loose or missing
fuel cap will allow fuel to evaporate into the atmosphere.
A few driving trips with the cap properly installed
should turn the light
off.
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition
will usually be corrected when the electrical system
dries out. A few driving trips should turn the light
off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane
on page 5-5. Poor fuel quality will
cause your engine not to run as efficiently as designed.
You may notice this as stalling after start-up, stalling
when you put the vehicle into gear, misfiring, hesitation
on acceleration or stumbling on acceleration. (These
conditions may go away once the engine is warmed up.)
This will be detected by the system and cause the
light to turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at least
one full tank
of the proper fuel to turn the light off.

Section 5 Service and Appearance Care
Service ............................................................ 5.3
Doing Your Own Service Work
......................... 5-3
Adding Equipment
to the Outside of Your
Vehicle
.................................................. 5-4
................................................................ Fuel 5.5
Gasoline Octane ............................................ 5.5
Gasoline Specifications ................................... 5-5
California Fuel ............................................... 5-6
Additives
....................................................... 5.6
Fuels in Foreign Countries
............................... 5-6
Filling Your Tank
............................................ 5-7
Filling a Portable Fuel Container ....................... 5.9
the Hood .................... , .................... 5.10
Hood Release ...................... ................ 5-10
Engine Compartment Overview ....... ......... 5-12
Engine Oil ....................................... ..... 5.13
Engine Air Cleaner/Filter ............................. 5.17
Automatic Transmission Fluid ......................... 5-20
Engine Coolant ......................................... 5-22
Checking Things Under
~~
Coolant Surge Tank Pressure Cap ............... 5-25
Engine Overheating ....................................... 5-25
Cooling System ............................................ 5.28
Engine Fan Noise ......................................... 5.33
Power Steering Fluid
..................................... 5-34
Windshield Washer Fluid
................................ 5.34
Brakes
........................................................ 5.36
Battery
........................................................ 5-39
Jump Starting
............................................... 5.40
All-Wheel Drive .............................................. 5.46
Rear Axle .................................. .......... 5-48
Bulb Replacement .......................................... 5-49
Halogen Bulbs .............................................. 5-49
Headlamps
.................................................. 5-49
Running Lamps
......................................... 5-50
Center High-Mounted Stoplamp (CHMSL) ......... 5-52
Taillamps ..................................................... 5-52
Replacement Bulbs ................................... 5.53
Front Turn Signal, Sidemarker and Daytime
5- 1

Fuel
Use of the recommended fuel is an important part of the
proper maintenance
of your vehicle.
Gasoline Octane
Use regular unleaded gasoline with a posted octane
of 87 or higher.
If the octane is less than 87, you may
get a heavy knocking noise when you drive. If this
occurs, use a gasoline rated at 87 octane or higher as
soon as possible. Otherwise, you might damage
your engine.
A little pinging noise when you accelerate
or drive uphill
is considered normal. This does not
indicate a problem exists or that a higher-octane fuel is
necessary. If you are using 87 octane or higher-octane
fuel and hear heavy knocking, your engine needs
service.
Gasoline Specifications
It is recommended that gasoline meet specifications
which were developed by the American Automobile
Manufacturers Association and endorsed
by the
Canadian Vehicle Manufacturers Association for better
vehicle performance and engine protection. Gasoline meeting these specifications could provide improved
driveability and emission control system performance
compared to other gasoline.
In Canada, look for the
"Auto Makers' Choice"
label on the pump.
Canada Only
5-5

California Fuel
If your vehicle is certified to meet California Emission
Standards (see the underhood emission control label), it
is designed
to operate on fuels that meet California
specifications.
If this fuel is not available in states
adopting California emissions standards, your vehicle
will operate satisfactorily on fuels meeting federal
specifications, but emission control system performance
may be affected. The malfunction indicator lamp may
turn on (see Malfunction Indicator Lamp on page
3-38 )
and your vehicle may fail a smog-check test. If this
occurs, return
to your authorized GM dealer for
diagnosis.
If it is determined that the condition is caused
by the type of fuel used, repairs may not be covered
by your warranty.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system
to work
properly. You should not have
to add anything to your
fuel. Gasolines containing oxygenates, such as ethers and ethanol, and reformulated gasolines may be
available in your area to contribute
to clean air.
General Motors recommends that you use these
gasolines, particularly
if they comply with the
specifications described earlier.
5-6
Notice: Your vehicle was not designed for fuel that
contains methanol. Don’t use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage wouldn’t be covered under your
warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors does
not recommend the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs and
the performance of the emission control system may
be affected. The malfunction indicator lamp may turn on.
If this occurs, return to your authorized GM dealer for
service.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may be hard
to find. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel wouldn’t be
covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you’ll be driving.

Part A: Scheduled Maintenance
Services
This part contains engine oil and chassis lubrication
scheduled maintenance which explains the engine oil life
system and how it indicates when
to change the
engine oil and filter. Lubricate chassis components with
each oil change.
Also, listed are scheduled maintenance
services which are to be performed at the mileage
intervals specified.
Using Your Maintenance Schedule
We at General Motors want to help you keep your
vehicle in good working condition. But we don’t know
exactly how you’ll drive it. You may drive very short
distances only a few times a week. Or you may drive
long distances all the time in very hot, dusty weather.
You may use your vehicle in making deliveries. Or
you may drive it to work,
to do errands or in many
other ways.
Because of all the different ways people use their
vehicles, maintenance needs vary. You may need more
frequent checks and replacements.
So please read
the following and note how you drive. If you have any
questions on how to keep your vehicle in good condition,
see your dealer. This part tells you
the maintenance services you should
have done and when you should schedule them.
When you go
to your dealer for your service needs,
you’ll know that GM-trained and supported service
people will perform the work using genuine GM parts.
The proper fluids and lubricants
to use are listed in
Part
D. Make sure whoever services your vehicle uses
these.
All parts should be replaced and all necessary
repairs done before you or anyone else drives the
vehicle.
This schedule is for vehicles that:
carry passengers and cargo within recommended
limits. You will find these limits on your vehicle’s
Certificationflire label. See Loading Your Vehicle
on
page 4-44.
are driven on reasonable road surfaces within legal
driving limits.
are driven off-road in the recommended manner.
See Operating Your All- Wheel-Drive Vehicle
Off
Paved Roads on page 4- 16.
use the recommended fuel. See Gasoline Octane
on page 5-5.
6-4

Exit Lighting ........................................ 3-16
Extender, Safety Belt
....................................... 1-47
Exterior Lamps
......................... ~ ~ ................ 3-1 3
FabricKarpet
...
Engine Air Cleaner ..............................
Finding a P TY Station (RDS and XMTM) .....
Filter
Finding a Station
....................................
F
....
Finish Care
Finish Damage
................................
Fixed Mast Antenna .........................
Flash-to-Pass ...................................
Flat Tire .........................................
Flat Tire, Changing ..........................
Fluid
Automatic Transmission
.................
Power Steering ............................
Windshield Washer .......................
-
.....................................
..
.....
...
.... 5-78
.... 5-17
.... 3-63
.... 3-61
.... 5-81
.... 5-83
.... 3-89
...... 3-8
.... 5-63
............. 5-63
.......... 5-20
.......... 5-34
.......... 5-34
FM Stereo
..................................................... 3-87
Fog Lamps
.................................................... 3-1 5
Folding the Seatback ....................................... 1-17
Folding the Seatbacks
............................. 1-12, 1-22
Folding the Seatbacks (60/40 Split Bench Seat) .... 1-9
Following Distance
.......................................... 4-53
Footnotes
........................................ ......... 6-5
Front Axle
.................................... ... 5-47 Frontal
Air Bags
...................................... 1-77
Fuel
............................................................... 5-5
Additives ...................................................... 5-6
California Fuel
.............................................. 5-6
Filling Your Tank
........................................... 5-7
Fuels in Foreign Countries
.......................... 5-6
Gasoline Octane
....................................... 5-5
Gasoline Specifications .................................. 5-5
System Inspection ....................................... 6-14
Filling
a Portable Fuel Container
..................... 5-9
Gage
............................. .................... 3-42
Low Warning Light
....................................... 3-42
Fuel Information Button
.................................... 3-45
FUEL LEVEL LOW
......................................... 3-55
Fuses
Fuses and Circuit Breakers
........................... 5-87
Windshield Wiper
......................................... 5-87
G
Gage
Engine Coolant Temperature
............. .... 3-36
Fuel
...................................................... 3-42
Oil Pressure
........................................... 3-40
Speedometer
.......................................... 3-30
Tachometer
............................................. 3-30
Transmission Temperature
......................... 3-37
Voltmeter Gage ....................................... 3-34
Garage Door Opener
....................................... 2-38
6

Gasoline Octane
........................................................ 5-5
Gate Operator and Canadian Programming ........ 2-40
Glass surfaces 3-o~
Glove Box ..................................................... 2-42
GM Mobility Program for Persons with
Disabilities
................................... 7-5
Specifications ............................................... 5-5
rn r nn ...............................................
H
Hazard Warning Flashers ............................... 3-5
Head Restraints
........................................... 1-6
Headlamp High/Low-Beam Changer
.................... 3-8
Headlamps
.................................................... 5-49
Bulb Replacement
....................................... 5-49
Front Turn Signal, Sidemarker and Daytime
Running Lamps
........................................ 5-50
Halogen Bulbs ............................................ 5-49
Headphones
................................................... 3-77
Heated Seats
................................................... 1-4
Heating
......................................................... 3-23
Highway Hypnosis
........................................... 4-35
Hill and Mountain Roads
.................................. 4-35
Hitches
.......................................................... 4-52
HomeLink Transmitter, Programming
.................. 2-38
HomeLinkO Transmitter
............................ 2-38
Hood Checking Things Under
................................ 5-10
Release
..................................................... 5-1 0
Horn ............................................................... 3-6
How
to Add Coolant to the Coolant Surge Tank ...... 5-29
How
to Add Fluid ............................................ 5-22
How
to Check ........................................ 5-20, 5-56
How to Check Lhrizzri-it ................................... 5-48
How
to Check Power Steering Fluid .................. 5-34
How
to Use This Manual ...................................... ii
How to Wear Safety Belts Properly ................... 1-30
Hydroplaning
.................................................. 4-31
I
If No Steam Is Coming From Your Engine .......... 5-27
If Steam Is Coming From Your Engine ............... 5-26
If the Light is Flashing
..................................... 3-39
If the Light Is On Steady ................................. 3-39
If You Are Stuck in Sand, Mud, Ice or Snow
....... 4-41
If You Do Decide To Pull
A Trailer ..................... 4-48
If You’re Caught in a Blizzard
........................... 4-39
Ignition Positions
............................................. 2-18
Ignition Transmission Lock Check
...................... 6-13
Illuminated Visor Vanity Mirrors
......................... 2-15
Infants and Young Children, Restraints
............... 1-50
Inflation -- Tire Pressure ..................... ..... 5-55
Inspection
Brake System
............................................. 6-14
Engine Cooling System
................................ 6-14
Exhaust System
.......................................... 6-14
Fuel System
............................................... 6-14
Part C
- Periodic Maintenance ....................... 6-14
7