2004 GMC YUKON DENALI fuel

Tow/Haul Mode
The Tow/Haul feature assists when pulling a heavy
trailer or a large or heavy load. The purpose of
the Tow/Haul mode is to:
·Reduce the frequency and improve the predictability
of transmission shifts when pulling a heavy trailer or
a large or heavy load.
·Provide the same solid shift feel when pulling a
heavy trailer or a large or heavy load as when
the vehicle is unloaded.
·Improve control of vehicle speed while requiring
less throttle pedal activity when pulling a heavy
trailer or a large or heavy load.
Your vehicle is provided with a button at the end of the
shift lever which when pressed enables Tow/Haul.
When the button is pressed, a light on the instrument
panel will illuminate to indicate that Tow/Haul has been
selected. Tow/Haul may be turned off by pressing
the button again, at which time the indicator light on the
instrument panel will turn off. The vehicle will
automatically turn off tow/haul every time it is started.Tow/Haul is designed to be most effective when the
vehicle and trailer combined weight is at least 75 percent
of the vehicle's Gross Combination Weight Rating
(GCWR). See ªWeight of the Trailerº later in this section.
Tow/Haul is most useful under the following driving
conditions:
·When pulling a heavy trailer or a large or heavy
load through rolling terrain.
·When pulling a heavy trailer or a large or heavy
load in stop and go traffic.
·When pulling a heavy trailer or a large or heavy
load in busy parking lots where improved low
speed control of the vehicle is desired.
Operating the vehicle in Tow/Haul when lightly loaded
or with no trailer at all will not cause damage. However,
there is no bene®t to the selection of Tow/Haul when
the vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a heavy
trailer or a large or heavy load.
4-53

Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside
of Your Vehicle...........................................5-4
Fuel................................................................5-4
Gasoline Octane............................................5-4
Gasoline Speci®cations....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling Your Tank............................................5-7
Filling a Portable Fuel Container.......................5-9
Checking Things Under
the Hood....................................................5-10
Hood Release..............................................5-10
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-13
Engine Air Cleaner/Filter................................5-18
Automatic Transmission Fluid.........................5-20
Engine Coolant.............................................5-23
Coolant Surge Tank Pressure Cap..................5-25Engine Overheating.......................................5-25
Cooling System............................................5-28
Engine Fan Noise.........................................5-33
Power Steering Fluid.....................................5-34
Windshield Washer Fluid................................5-35
Brakes........................................................5-36
Battery........................................................5-39
Jump Starting...............................................5-40
All-Wheel Drive..............................................5-45
Rear Axle.......................................................5-46
Front Axle......................................................5-47
Bulb Replacement..........................................5-48
Halogen Bulbs..............................................5-48
Headlamps..................................................5-48
Front Turn Signal, Sidemarker and
Daytime Running Lamps.............................5-49
Center High-Mounted Stoplamp (CHMSL).........5-51
Taillamps.....................................................5-51
Replacement Bulbs.......................................5-52
Section 5 Service and Appearance Care
5-1

CAUTION: (Continued)
·
Be sure to use the proper nuts, bolts and
other fasteners. ªEnglishº and ªmetricº
fasteners can be easily confused. If you
use the wrong fasteners, parts can later
break or fall off. You could be hurt.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the air¯ow around it. This may cause wind
noise and affect windshield washer performance.
Check with your dealer before adding equipment to the
outside of your vehicle.
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.
5-4

Gasoline Speci®cations
It is recommended that gasoline meet speci®cations
which were developed by automobile manufacturers
around the world and contained in the World-Wide Fuel
Charter which is available from the Alliance of
Automobile Manufacturers at www.autoalliance.org.
Gasoline meeting these speci®cations could provide
improved driveability and emission control system
performance compared to other gasoline.
In Canada, look for the
ªAuto Makers' Choiceº
label on the pump.
California Fuel
If your vehicle is certi®ed to meet California Emission
Standards (see the underhood emission control label),
it is designed to operate on fuels that meet California
speci®cations. If this fuel is not available in states
adopting California emissions standards, your vehicle
will operate satisfactorily on fuels meeting federal
speci®cations, but emission control system performance
may be affected. The malfunction indicator lamp may
turn on (see
Malfunction Indicator Lamp on page 3-40)
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.
Canada Only
5-5

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. However, some gasolines contain only the
minimum amount of additive required to meet U.S.
Environmental Protection Agency regulations. General
Motors recommends that you buy gasolines that
are advertised to help keep fuel injectors and intake
valves clean. If your vehicle experiences problems due
to dirty injectors or valves, try a different brand of
gasoline.
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 speci®cations described earlier.
Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage would not 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.
5-6

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 ®nd. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel would not
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 will be driving.
Filling Your Tank
{CAUTION:
Fuel vapor burns violently and a fuel ®re can
cause bad injuries. To help avoid injuries to
you and others, read and follow all the
instructions on the pump island. Turn off your
engine when you are refueling. Do not smoke
if you are near fuel or refueling your vehicle.
CAUTION: (Continued)
CAUTION: (Continued)
Keep sparks, ¯ames and smoking materials
away from fuel. Do not leave the fuel pump
unattended when refueling your vehicle Ð this
is against the law in some places. Keep
children away from the fuel pump; never let
children pump fuel.
The fuel cap is located behind a hinged door on the
driver's side of the vehicle.
While refueling, hang the
fuel cap by the tether
using the hook located
on the inside of the
®ller door.
5-7

To remove the fuel cap, turn it slowly to the left
(counterclockwise). It will require more effort to turn the
fuel cap on the last turn as you loosen it.
{CAUTION:
If you spill fuel and then something ignites it,
you could be badly burned. Fuel can spray out
on you if you open the fuel cap too quickly.
This spray can happen if your tank is nearly
full, and is more likely in hot weather. Open
the fuel cap slowly and wait for any ªhissº
noise to stop. Then unscrew the cap all
the way.Be careful not to spill fuel. Don't top off or over®ll your
tank and wait a few seconds after you've ®nished
pumping before you remove the nozzle. Clean any
spilled fuel from painted surfaces as soon as possible.
See
Cleaning the Outside of Your Vehicle on
page 5-96.
When you put the fuel cap back on, turn it to the right
(clockwise) until you hear a clicking sound. It will require
more effort to turn the fuel cap on the last turn as you
tighten it. Make sure you fully install the cap. The
diagnostic system can determine if the fuel cap has
been left off or improperly installed. this would allow fuel
to evaporate into the atmosphere. See
Malfunction
Indicator Lamp on page 3-40.
5-8

{CAUTION:
If a ®re starts while you are refueling, do not
remove the nozzle. Shut off the ¯ow of fuel by
shutting off the pump or by notifying the
station attendant. Leave the area immediately.
Notice:If you need a new fuel cap, be sure to get
the right type. Your dealer can get one for you.
If you get the wrong type, it may not ®t properly.
This may cause your malfunction indicator lamp to
light and may damage your fuel tank and emissions
system. See
Malfunction Indicator Lamp on
page 3-40.
Filling a Portable Fuel Container
{CAUTION:
Never ®ll a portable fuel container while it is in
your vehicle. Static electricity discharge from
the container can ignite the gasoline vapor.
You can be badly burned and your vehicle
damaged if this occurs. To help avoid injury to
you and others:
·Dispense gasoline only into approved
containers.
·Do not ®ll a container while it is inside a
vehicle, in a vehicle's trunk, pickup bed or
on any surface other than the ground.
·Bring the ®ll nozzle in contact with the
inside of the ®ll opening before operating
the nozzle. Contact should be maintained
until the ®lling is complete.
·Do not smoke while pumping gasoline.
5-9