2003 GMC YUKON DENALI gas type

in frontal and near-frontal impacts. For side impact air
bags, inflation is determined by the location and severity
of the impact.
The air bag system is designed to work properly under
a wide range of conditions, including off-road usage.
Observe safe driving speeds, especially on rough
terrain. As always, wear your safety belt. See Operating
Your
All- Wheel-Drive Vehicle Off Paved Roads on
page
4-16 for tips on off-road driving.
What Makes an Air Bag Inflate?
In an impact of sufficient severity, the air bag sensing
system detects that the vehicle is in a crash. For
both frontal and side impact air bags, the sensing
system triggers a release
of gas from the inflator, which
inflates the air bag. The inflator, the air bag and
related hardware are all part of the air bag modules.
Frontal air bag modules are located inside the steering
wheel and instrument panel. For vehicles with side
impact air bags, the air bag modules are located in the
seatback closest
to the driver’s and/or right front
passenger’s door.
How Does an Air Bag Restrain?
In moderate to severe frontal or near frontal collisions,
even belted occupants can contact the steering wheel or
the instrument panel. In moderate
to severe side
collisions, even belted occupants can contact the inside
of the vehicle. The air bag supplements the protection
provided by safety belts. Air bags distribute the force of
the impact more evenly over the occupant’s upper
body, stopping the occupant more gradually. But the
frontal air bags would not help you in many types
of collisions, including rollovers, rear impacts, and many
side impacts, primarily because an occupant’s motion
is not toward the air bag. Side impact air bags would not
help you in many types of collisions, including frontal
or near frontal collisions, rollovers, and rear impacts,
primarily because an occupant’s motion is not toward
those air bags. Air bags should never be regarded
as anything more than a supplement
to safety belts, and
then only in moderate
to severe frontal or near-frontal
collisions for the driver’s and right front passenger’s
frontal air bags, and only in moderate to severe
side collisions for vehicles with a driver’s and right front
passenger’s side impact air bag.
1-78

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.

When you put the fuel cap back on, turn it to the right
(clockwise) until you hear a clicking sound. 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 3-38.
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 fit properly.
This may cause your malfunction indicator lamp to
light and may damage your fuel tank and emissions
system. See “Malfunction Indicator Lamp”
in the
Index.
Cillinc a Dortable Fun’ Container
~~ ~
Never fill 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 fill 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 fill nozzle in contact with the
inside of the fill opening before operating
the nozzle. Contact should be maintained until the filling is complete.
Don’t smoke while pumping gasoline.
5-9

Bulb Replacement
See Replacement Bulbs on page 5-53 for the proper
type
of bulbs to use.
For any bulb changing procedure not listed in this
section, contact your dealer.
Halogen Bulbs
Halogen bulbs have pressurized gas inside
and can burst if you drop or scratch the bulb.
You or others could be injured. Be sure to read
and
follow the instructions on the bulb
package.
Headlamps
1. Remove the two pins on the top of the headlamp
assembly.
To remove the pins, turn the outer pin
outward and pull
it straight up. To remove the inner
pin, turn it inward and pull it straight up.
5-49