ECU GMC SIERRA 2018 User Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
72 Seats and Restraints
The lap-shoulder belt may lock
if you pull the belt across you
very quickly. If this happens, let
the belt go back slightly to
unlock it. Then pull the belt
across you more slowly.
If the shoulder portion of a
passenger belt is pulled out all
the way, the child restraint
locking feature may be
engaged. If this happens, let
the belt go back all the way
and start again.
Engaging the child restraint
locking feature in the front
outboard seating position may
affect the passenger sensing
system, if equipped. See
Passenger Sensing System
086.
If the webbing locks in the latch
plate before it reaches the
buckle, tilt the latch plate flat to
unlock.
3. Push the latch plate into the
buckle until it clicks.
Pull up on the latch plate to
make sure it is secure. If the
belt is not long enough, see
Seat Belt Extender 075.
Position the release button on
the buckle so that the seat belt
could be quickly unbuckled if
necessary.
4. If equipped with a shoulder belt height adjuster, move it to the
height that is right for you. See
“Shoulder Belt Height Adjuster”
later in this section for
instructions on use and
important safety information.

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Seats and Restraints 75
Lap Belt
This section is only for the lap belt.
To learn how to wear a lap-shoulder
belt, seeLap-Shoulder Belt 071.
The vehicle may have a center
seating position with a lap seat belt.
The lap seat belt does not have a
retractor.
To make the belt longer, tilt the latch
plate and pull it along the belt.
Buckle, position, and release it the
same way as the lap part of a
lap-shoulder belt.
To make the belt shorter, pull its free
end as shown until the belt is snug.
If the belt is not long enough, see
Seat Belt Extender 075.
Make sure the release button on the
buckle is positioned so you would
be able to unbuckle the seat belt
quickly if necessary.
Seat Belt Extender
If the vehicle's seat belt will fasten
around you, you should use it.
But if a seat belt is not long enough,
your dealer will order you an
extender. When you go in to order it, take the heaviest coat you will wear,
so the extender will be long enough
for you. To help avoid personal
injury, do not let someone else use
it, and use it only for the seat it is
made to fit. The extender has been
designed for adults. Never use it for
securing child restraints. For more
information on the proper use and fit
of seat belt extenders see the
instruction sheet that comes with
the extender.
Safety System Check
Periodically check the seat belt
reminder, seat belts, buckles, latch
plates, retractors, shoulder belt
height adjusters (if equipped), and
seat belt anchorages to make sure
they are all in working order. Look
for any other loose or damaged seat
belt system parts that might keep a
seat belt system from performing
properly. See your dealer to have it
repaired. Torn or frayed seat belts
may not protect you in a crash.
They can rip apart under impact
forces. If a belt is torn or frayed,
have it replaced immediately.

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78 Seats and Restraints
Warning (Continued)
seriously injured or killed. Do not
sit unnecessarily close to any
airbag, as you would be if sitting
on the edge of the seat or leaning
forward. Seat belts help keep you
in position before and during a
crash. Always wear a seat belt,
even with airbags. The driver
should sit as far back as possible
while still maintaining control of
the vehicle. The seat belts and
the front outboard passenger
airbags are most effective when
you are sitting well back and
upright in the seat with both feet
on the floor.
Occupants should not lean on or
sleep against the door or side
windows in seating positions with
seat-mounted side impact airbags
and/or roof-rail airbags.
{Warning
Children who are up against,
or very close to, any airbag when
it inflates can be seriously injured
or killed. Always secure children
properly in the vehicle. To read
how, seeOlder Children 092 or
Infants and Young Children 094.
There is an airbag readiness light
on the instrument cluster, which
shows the airbag symbol.
The system checks the airbag
electrical system for malfunctions.
The light tells you if there is an
electrical problem. See Airbag
Readiness Light 0147 for more
information.
Where Are the Airbags?
The driver frontal airbag is in the
center of the steering wheel.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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80 Seats and Restraints
Warning (Continued)
that person causing severe injury
or even death. The path of an
inflating airbag must be kept
clear. Do not put anything
between an occupant and an
airbag, and do not attach or put
anything on the steering wheel
hub or on or near any other
airbag covering.
Do not use seat accessories that
block the inflation path of a
seat-mounted side impact airbag.
Never secure anything to the roof
of a vehicle with roof-rail airbags
by routing a rope or tie‐down
through any door or window
opening. If you do, the path of an
inflating roof-rail airbag will be
blocked.
When Should an Airbag
Inflate?
This vehicle is equipped with
airbags. SeeAirbag System 077.
Airbags are designed to inflate if the
impact exceeds the specific airbag
system's deployment threshold.
Deployment thresholds are used to
predict how severe a crash is likely
to be in time for the airbags to
inflate and help restrain the
occupants. The vehicle has
electronic sensors which help the
airbag system determine the
severity of the impact. Deployment
thresholds can vary with specific
vehicle design.
Frontal airbags are designed to
inflate in moderate to severe frontal
or near frontal crashes to help
reduce the potential for severe
injuries, mainly to the driver's or
front outboard passenger's head
and chest.
Whether the frontal airbags will or
should inflate is not based primarily
on how fast the vehicle is traveling. It depends on what is hit, the
direction of the impact, and how
quickly the vehicle slows down.
Frontal airbags may inflate at
different crash speeds depending on
whether the vehicle hits an object
straight on or at an angle, and
whether the object is fixed or
moving, rigid or deformable, narrow
or wide.
Frontal airbags are not intended to
inflate during vehicle rollovers, in
rear impacts, or in many side
impacts.
In addition, if the GVWR (Gross
Vehicle Weight Rating) is at or
below 3 855 kg (8,500 lb), the
vehicle has advanced technology
frontal airbags. You can find the
GVWR on the Certification/Tire label
on the center pillar of the vehicle.
See
Vehicle Load Limits 0248 for
more information.
Advanced technology frontal airbags
adjust the restraint according to
crash severity. Vehicles with
advanced technology frontal airbags
have a seat position sensor that

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86 Seats and Restraints
The front outboard passenger
frontal airbag is now enabled
(may inflate). SeeAirbag On-Off
Light 0147.
Passenger Sensing
System
If the vehicle has one of the
following indicators, then the vehicle
has a passenger sensing system for
the front outboard passenger
position, unless there is an airbag
on-off switch on the instrument
panel endcap. If there is an airbag
on-off switch, the vehicle does not
have a passenger sensing system.
See Airbag On-Off Switch 084 for
more information.
The passenger airbag status
indicator will light on the overhead
console when the vehicle is started.
United States
Canada and Mexico
The words ON and OFF, or the
symbol for on and off, will be visible
during the system check. When the
system check is complete, either the
word ON or OFF, or the symbol for
on or off, will be visible. See
Passenger Airbag Status Indicator
0 149.
The passenger sensing system
turns off the front outboard
passenger frontal airbag under
certain conditions. No other airbag
is affected by the passenger
sensing system. The passenger sensing system
works with sensors that are part of
the front outboard passenger seat
and seat belt. The sensors are
designed to detect the presence of
a properly seated occupant and
determine if the front outboard
passenger frontal airbag should be
allowed to inflate or not.
According to accident statistics,
children are safer when properly
secured in a rear seat in the correct
child restraint for their weight
and size.
Whenever possible, children aged
12 and under should be secured in
a rear seating position.
Never put a rear-facing child seat in
the front. This is because the risk to
the rear-facing child is so great,
if the airbag inflates.
{Warning
A child in a rear-facing child
restraint can be seriously injured
or killed if the passenger frontal
(Continued)

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Seats and Restraints 87
Warning (Continued)
airbag inflates. This is because
the back of the rear-facing child
restraint would be very close to
the inflating airbag. A child in a
forward-facing child restraint can
be seriously injured or killed if the
passenger frontal airbag inflates
and the passenger seat is in a
forward position.
Even if the passenger sensing
system has turned off the
passenger frontal airbag, no
system is fail-safe. No one can
guarantee that an airbag will not
deploy under some unusual
circumstance, even though the
airbag is turned off.
Never put a rear-facing child
restraint in the front seat, even if
the airbag is off. If securing a
forward-facing child restraint in
the front outboard passenger
seat, always move the seat as far
back as it will go. It is better to(Continued)
Warning (Continued)
secure child restraints in the rear
seat. Consider using another
vehicle to transport the child
when a rear seat is not available.
If the vehicle does not have a rear
seat that will accommodate a
rear-facing child restraint, a
rear-facing child restraint should not
be installed in the vehicle, even if
the airbag is off.
The passenger sensing system is
designed to turn off the front
outboard passenger frontal airbag if:
. The front outboard passenger
seat is unoccupied.
. The system determines an infant
is present in a child restraint.
. A front outboard passenger
takes his/her weight off of the
seat for a period of time.
. There is a critical problem with
the airbag system or the
passenger sensing system. When the passenger sensing
system has turned off the front
outboard passenger frontal airbag,
the off indicator will light and stay lit
as a reminder that the airbag is off.
See
Passenger Airbag Status
Indicator 0149.
The passenger sensing system is
designed to turn on the front
outboard passenger frontal airbag
anytime the system senses that a
person of adult size is sitting
properly in the front outboard
passenger seat.
When the passenger sensing
system has allowed the airbag to be
enabled, the on indicator will light
and stay lit as a reminder that the
airbag is active.
For some children, including
children in child restraints, and for
very small adults, the passenger
sensing system may or may not turn
off the front outboard passenger
frontal airbag, depending upon the
person's seating posture and body
build. Everyone in the vehicle who
has outgrown child restraints should

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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88 Seats and Restraints
wear a seat belt properly—whether
or not there is an airbag for that
person.
{Warning
If the airbag readiness light ever
comes on and stays on, it means
that something may be wrong
with the airbag system. To help
avoid injury to yourself or others,
have the vehicle serviced right
away. See Airbag Readiness
Light 0147 for more information,
including important safety
information.
If the On Indicator Is Lit for a
Child Restraint
The passenger sensing system is
designed to turn off the front
outboard passenger frontal airbag if
the system determines that an infant
is present in a child restraint. If a
child restraint has been installed
and the on indicator is lit:
1. Turn the vehicle off. 2. Remove the child restraint from
the vehicle.
3. Remove any additional items from the seat such as blankets,
cushions, seat covers, seat
heaters, or seat massagers.
4. Reinstall the child restraint following the directions
provided by the child restraint
manufacturer and refer to
Securing Child Restraints (With
the Seat Belt in the Center
Front Seat) 0114 orSecuring
Child Restraints (With the Seat
Belt in the Front Passenger
Seat) 0115 orSecuring Child
Restraints (With the Seat Belt
in the Rear Seat) 0111.
Make sure the seat belt
retractor is locked by pulling
the shoulder belt all the way
out of the retractor when
installing the child restraint,
even if the child restraint is
equipped with a seat belt lock
off. When the retractor lock is
set, the belt can be tightened
but not pulled out of the
retractor. 5. If, after reinstalling the child
restraint and restarting the
vehicle, the on indicator is still
lit, turn the vehicle off. Then
slightly recline the vehicle
seatback and adjust the seat
cushion, if adjustable, to make
sure that the vehicle seatback
is not pushing the child
restraint into the seat cushion.
Also make sure the child
restraint is not trapped under
the vehicle head restraint.
If this happens, adjust the head
restraint. See Head Restraints
0 58.
6. Restart the vehicle.
The passenger sensing system may
or may not turn off the airbag for a
child in a child restraint depending
upon the child’s size. It is better to
secure child restraints in the rear
seat. Consider using another
vehicle to transport the child when a
rear seat is not available. Never put
a rear-facing child restraint in the
front seat, even if the on indicator is
not lit.

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Warning (Continued)
infant will suddenly become a
110 kg (240 lb) force on a person's
arms. An infant or child should be
secured in an appropriate
restraint.
{Warning
Children who are up against,
or very close to, any airbag when
it inflates can be seriously injured(Continued)
Warning (Continued)
or killed. Never put a rear-facing
child restraint in the front
outboard seat. Secure a
rear-facing child restraint in a rear
seat. It is also better to secure a
forward-facing child restraint in a
rear seat. If you must secure a
forward-facing child restraint in
the front outboard seat, always
move the front passenger seat as
far back as it will go.
Child restraints are devices used to
restrain, seat, or position children in
the vehicle and are sometimes
called child seats or car seats.
There are three basic types of
child restraints:
.Forward-facing child restraints
. Rearward-facing child restraints
. Belt-positioning booster seats
The proper child restraint for your
child depends on their size, weight,
and age, and also on whether the
child restraint is compatible with the
vehicle in which it will be used.
For each type of child restraint,
there are many different models
available. When purchasing a child
restraint, be sure it is designed to be
used in a motor vehicle. If it is, the
restraint will have a label saying that
it meets federal motor vehicle safety
standards. The restraint
manufacturer's instructions that
come with the restraint state the
weight and height limitations for a
particular child restraint. In addition,

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96 Seats and Restraints
there are many kinds of restraints
available for children with special
needs.
{Warning
To reduce the risk of neck and
head injury in a crash, infants and
toddlers should be secured in a
rear-facing child restraint until age
two, or until they reach the
maximum height and weight limits
of their child restraint.
{Warning
A young child's hip bones are still
so small that the vehicle's regular
seat belt may not remain low on
the hip bones, as it should.
Instead, it may settle up around
the child's abdomen. In a crash,
the belt would apply force on a
body area that is unprotected by
any bony structure. This alone
could cause serious or fatal(Continued)
Warning (Continued)
injuries. To reduce the risk of
serious or fatal injuries during a
crash, young children should
always be secured in appropriate
child restraints.
Child Restraint Systems
Rear-Facing Infant Restraint
A rear-facing child restraint provides
restraint with the seating surface
against the back of the infant. The harness system holds the infant
in place and, in a crash, acts to
keep the infant positioned in the
restraint.
Forward-Facing Child Restraint
A forward-facing child restraint
provides restraint for the child's
body with the harness.

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Booster Seats
A belt-positioning booster seat is
used for children who have
outgrown their forward-facing child
restraint. Boosters are designed to
improve the fit of the vehicle's seat
belt system until the child is large
enough for the vehicle seat belts to
fit properly without a booster seat.
See the seat belt fit test in Older
Children 092.
Securing an Add-On Child
Restraint in the Vehicle
{Warning
A child can be seriously injured or
killed in a crash if the child
restraint is not properly secured in
the vehicle. Secure the child
restraint properly in the vehicle
using the vehicle’s seat belt or
LATCH system, following the
instructions that came with that
child restraint and the instructions
in this manual.
To help reduce the chance of injury,
the child restraint must be secured
in the vehicle. Child restraints must
be secured in vehicle seats by lap
belts or the lap belt portion of a
lap-shoulder belt, or by the LATCH
system. See Lower Anchors and
Tethers for Children (LATCH
System) 099 for more information.
Children can be endangered in a
crash if the child restraint is not
properly secured in the vehicle. When securing an add-on child
restraint, refer to the instructions
that come with the restraint which
may be on the restraint itself or in a
booklet, or both, and to this manual.
The child restraint instructions are
important, so if they are not
available, obtain a replacement
copy from the manufacturer.
Keep in mind that an unsecured
child restraint can move around in a
collision or sudden stop and injure
people in the vehicle. Be sure to
properly secure any child restraint in
the vehicle
—even when no child is
in it.
In some areas of the United States
and Canada, Certified Child
Passenger Safety Technicians
(CPSTs) are available to inspect
and demonstrate how to correctly
use and install child restraints. In
the U.S., refer to the National
Highway Traffic Safety
Administration (NHTSA) website to
locate the nearest child safety seat
inspection station. For CPST