2018 GMC SIERRA ECU

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Seats and Restraints 57
Seats and
Restraints
Head Restraints
Head Restraints . . . . . . . . . . . . . . . 58
Front Seats
Seat Adjustment . . . . . . . . . . . . . . . 59
Center Seat . . . . . . . . . . . . . . . . . . . . 59
Power Seat Adjustment . . . . . . . . 60
Lumbar Adjustment . . . . . . . . . . . . 60
Reclining Seatbacks . . . . . . . . . . . 61
Memory Seats . . . . . . . . . . . . . . . . . 62
Heated and Ventilated FrontSeats . . . . . . . . . . . . . . . . . . . . . . . . . 65
Rear Seats
Rear Seats (Double Cab FullBench) . . . . . . . . . . . . . . . . . . . . . . . 66
Rear Seats (Split Bench) . . . . . . 68
Seat Belts
Seat Belts . . . . . . . . . . . . . . . . . . . . . 69
How to Wear Seat Belts Properly . . . . . . . . . . . . . . . . . . . . . . 70
Lap-Shoulder Belt . . . . . . . . . . . . . 71
Seat Belt Use During Pregnancy . . . . . . . . . . . . . . . . . . . . 74
Lap Belt . . . . . . . . . . . . . . . . . . . . . . . 75 Seat Belt Extender . . . . . . . . . . . . . 75
Safety System Check . . . . . . . . . . 75
Seat Belt Care . . . . . . . . . . . . . . . . . 76
Replacing Seat Belt System
Parts after a Crash . . . . . . . . . . . 76
Airbag System
Airbag System . . . . . . . . . . . . . . . . . 77
Where Are the Airbags? . . . . . . . 78
When Should an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . . 80
What Makes an Airbag Inflate? . . . . . . . . . . . . . . . . . . . . . . . 82
How Does an Airbag Restrain? . . . . . . . . . . . . . . . . . . . . . 82
What Will You See after an Airbag Inflates? . . . . . . . . . . . . . . 82
Airbag On-Off Switch . . . . . . . . . . 84
Passenger Sensing System . . . 86
Servicing the Airbag-Equipped Vehicle . . . . . . . . . . . . . . . . . . . . . . . 90
Adding Equipment to the Airbag-Equipped Vehicle . . . . . 90
Airbag System Check . . . . . . . . . . 91
Replacing Airbag System Parts after a Crash . . . . . . . . . . . . . . . . . 92
Child Restraints
Older Children . . . . . . . . . . . . . . . . . 92
Infants and Young Children . . . . 94
Child Restraint Systems . . . . . . . 96 Where to Put the Restraint . . . . . 98
Lower Anchors and Tethers for
Children (LATCH System) . . . . 99
Replacing LATCH System Parts After a Crash . . . . . . . . . . 111
Securing Child Restraints (With the Seat Belt in the
Rear Seat) . . . . . . . . . . . . . . . . . . 111
Securing Child Restraints (With the Seat Belt in the Center
Front Seat) . . . . . . . . . . . . . . . . . . 114
Securing Child Restraints (With the Seat Belt in the Front
Passenger Seat) . . . . . . . . . . . . 115

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Seats and Restraints 59
Rear Seats
The rear seat has adjustable
headrests in the outboard seating
positions.
The height of the headrest can be
adjusted. Pull the headrest up to
raise it. To lower the headrest, push
the headrest down.
If you are installing a child restraint
in the rear seat, see“Securing a
Child Restraint Designed for the
LATCH System” underLower
Anchors and Tethers for Children
(LATCH System) 099.
Front Seats
Seat Adjustment
{Warning
You can lose control of the
vehicle if you try to adjust a driver
seat while the vehicle is moving.
Adjust the driver seat only when
the vehicle is not moving.
To adjust a manual seat:
1. Pull the handle at the front of the seat. 2. Slide the seat to the desired
position and release the
handle.
3. Try to move the seat back and forth to be sure it is locked in
place.
To adjust the seatback, see
Reclining Seatbacks 061.
To adjust the lumbar support,
if equipped, see Lumbar Adjustment
0 60.
Center Seat
If equipped, the center front
seatback doubles as an armrest and
cupholder/storage area for the driver
and passenger when the center
front seat is not used. Do not use it
as a seating position when the
seatback is folded down.

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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
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/
Mexico-11349177) - 2018 - CRC - 10/17/17
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

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
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)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
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