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Black plate (31,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
Seats and Restraints 3-31
roof-rail airbags are designed to
inflate during a rollover or in a
severe frontal impact. Roof-rail
airbags are not designed to inflate in
rear impacts. Both roof-rail airbags
will inflate when either side of the
vehicle is struck, if the sensing
system predicts that the vehicle is
about to roll over on its side, or in a
severe frontal impact.
In any particular crash, no one can
say whether an airbag should have
inflated simply because of the
vehicle damage or the repair costs.
What Makes an Airbag
Inflate?
In a deployment event, the sensing
system sends an electrical signal
triggering a release of gas from the
inflator. Gas from the inflator fills the
airbag causing the bag to break out
of the cover. The inflator, the airbag,
and related hardware are all part of
the airbag module.
For airbag locations, seeWhere Are
the Airbags? on page 3-28.
How Does an Airbag
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.
Airbags supplement the protection
provided by safety belts by
distributing the force of the impact
more evenly over the
occupant's body.
Rollover capable roof-rail airbags
are also designed to help contain
the head and chest of occupants in
the outboard seating positions in the
first, second, and third rows. The
rollover capable roof-rail airbags are
designed to help reduce the risk of
full or partial ejection in rollover
events, although no system can
prevent all such ejections. But airbags would not help in many
types of collisions, primarily
because the occupant's motion is
not toward those airbags. See
When
Should an Airbag Inflate? on
page 3-30 for more information.
Airbags should never be regarded
as anything more than a supplement
to safety belts.
What Will You See after
an Airbag Inflates?
After the frontal airbags and
seat-mounted side impact airbags
inflate, they quickly deflate, so
quickly that some people may not
even realize an airbag inflated. The
front center airbag and roof-rail
airbags may still be at least partially
inflated for some time after they
inflate. Some components of the
airbag module may be hot for
several minutes. For location of the
airbags, see Where Are the
Airbags? on page 3-28.
Page 274 of 439

Black plate (67,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
Driving and Operating 9-67
available in some cities. If these
gasolines comply with the
previously described specification,
then they are acceptable to use.
However, E85 (85% ethanol) and
other fuels containing more than
15% ethanol must be used only in
FlexFuel vehicles.
{Caution
Do not use fuel containing
methanol. It can corrode metal
parts in the fuel system and also
damage plastic and rubber parts.
That damage would not be
covered under the vehicle
warranty.
Some gasolines, mainly high octane
racing gasolines, can contain an
octane-enhancing additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). Do not use
gasolines and/or fuel additives with
MMT as they can reduce spark plug
life and affect emission control
system performance. The malfunction indicator lamp may turn
on. If this occurs, see your dealer
for service.
California Fuel
Requirements
If the vehicle is certified to meet
California Emissions Standards, it is
designed to operate on fuels that
meet California specifications. See
the underhood emission control
label. If this fuel is not available in
states adopting California Emissions
Standards, the vehicle will operate
satisfactorily on fuels meeting
federal specifications, but emission
control system performance might
be affected. The malfunction
indicator lamp could turn on and the
vehicle may not pass a smog-check
test. See
Malfunction Indicator
Lamp on page 5-20. If this occurs,
return to your authorized dealer for
diagnosis. If it is determined that the
condition is caused by the type of
fuel used, repairs may not be
covered by the vehicle warranty.
Fuels in Foreign
Countries
If planning to drive in countries
outside the U.S. or Canada, the
proper fuel might be hard to find.
Check regional auto club or fuel
retail brand websites for availability
in the country where driving. Never
use leaded gasoline, fuel containing
methanol, manganese, or any other
fuel not recommended. Costly
repairs caused by use of improper
fuel would not be covered by the
vehicle warranty.
Fuel Additives
To keep fuel systems clean, TOP
TIER Detergent Gasoline is
recommended. See Fuel on
page 9-66.
If TOP TIER Detergent Gasoline is
not available, one bottle of Fuel
System Treatment PLUS added to
the fuel tank at every engine oil
change, can help. Fuel System
Treatment PLUS is the only
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Black plate (69,1)GMC 2015i Yukon Denali/Yukon XL Denali Owner Manual (GMNA-
Localizing-U.S./Canada/Mexico-8431504) - 2015 - CRC - 7/30/14
Driving and Operating 9-69
nozzle. Clean fuel from painted
surfaces as soon as possible. See
Exterior Care on page 10-81.
When replacing the fuel cap, insert
the tether in its hole before
tightening the cap. Turn the fuel cap
clockwise until it clicks. It will require
more effort to turn the fuel cap on
the last turn as you tighten it. Make
sure the cap is fully installed. 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. SeeMalfunction
Indicator Lamp on page 5-20.
The TIGHTEN GAS CAP message
displays if the fuel cap is not
properly installed.
{Warning
If a fire starts while you are
refueling, do not remove the
nozzle. Shut off the flow of fuel by
(Continued)
Warning (Continued)
shutting off the pump or by
notifying the station attendant.
Leave the area immediately.
{Caution
If a new fuel cap is needed, be
sure to get the right type of cap
from your dealer. The wrong type
of fuel cap may not fit properly,
may cause the malfunction
indicator lamp to light, and could
damage the fuel tank and
emissions system. See
Malfunction Indicator Lamp on
page 5-20.
Filling a Portable Fuel
Container
{Warning
Filling a portable fuel container
while it is in the vehicle can cause
fuel vapors that can ignite either
by static electricity or other
means. You or others could be
badly burned and the vehicle
could be damaged. Always:
.Use approved fuel
containers.
.Remove the container from
the vehicle, trunk, or pickup
bed before filling.
.Place the container on the
ground.
.Place the nozzle inside the fill
opening of the container
before dispensing fuel, and(Continued)