2024 GMC SIERRA ECU

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Seats and Restraints 71
.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
0 121.
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 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 0121
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) 092 or
Securing Child Restraints (With the Seat
Belt in the Rear Seat) 092 or
Securing Child Restraints (With the Seat
Belt in the Front Passenger Seat) 095.
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 047.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
72 Seats and Restraints
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.
If the Off Indicator Is Lit for an
Adult-Sized Occupant
If a person of adult size is sitting in the
front outboard passenger seat, but the OFF
indicator is lit, it could be because that
person is not sitting properly in the seat or that the child restraint locking feature is
engaged. Use the following steps to allow
the system to detect that person and enable
the front outboard passenger frontal airbag:
1. Turn the vehicle off.
2. Remove any additional material from the seat, such as blankets, cushions, seat
covers, seat heaters, or seat massagers.
3. Place the seatback in the fully upright position.
4. Have the person sit upright in the seat, centered on the seat cushion, with legs
comfortably extended.
5. If the shoulder portion of the belt is pulled out all the way, the child restraint
locking feature will be engaged. This
may unintentionally cause the passenger
sensing system to turn the airbag off for
some adult-sized occupants. If this
happens, unbuckle the belt, let the belt
go back all the way, and then buckle the
belt again without pulling the belt out
all the way.
6. Restart the vehicle and have the person remain in this position for two to
three minutes after the ON indicator
is lit.
{Warning
If the front outboard passenger airbag is
turned off for an adult-sized occupant,
the airbag will not be able to inflate and
help protect that person in a crash,
resulting in an increased risk of serious
injury or even death. An adult-sized
occupant should not ride in the front
outboard passenger seat, if the passenger
airbag OFF indicator is lit.
Additional Factors Affecting System
Operation
Seat belts help keep the passenger in
position on the seat during vehicle
maneuvers and braking, which helps the
passenger sensing system maintain the
passenger airbag status. See “Seat Belts”
and “Child Restraints” in the Index for
additional information about the importance
of proper restraint use.
A thick layer of additional material, such as
a blanket or cushion, or aftermarket
equipment such as seat covers, seat heaters,
and seat massagers can affect how well the
passenger sensing system operates. We
recommend that you not use seat covers or
other aftermarket equipment except when

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Seats and Restraints 77
Warning (Continued)
is not possible to hold it during a crash.
For example, in a crash at only
40 km/h (25 mph), a 5.5 kg (12 lb) 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
child restraint.
{Warning
Children who are up against, or very
close to, any airbag when it inflates can
be seriously injured or killed. Never put a
rear-facing child restraint in the front(Continued)
Warning (Continued)
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
.Rear-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 and
is designed by a genuine child restraint
manufacturer. If it is, the child restraint will
have a label saying that it meets federal
motor vehicle safety standards.
The instruction manual that is provided with
the child restraint states the weight and
height limitations for that particular child
restraint. In addition, there are many kinds
of child restraints available for children with
special needs.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
78 Seats and Restraints
{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 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 injuries.
To reduce the risk of serious or fatal
injuries during a crash, young children
should always be secured in an
appropriate child restraint.
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Seats and Restraints 79
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
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 Children075.
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 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 the lap belt portion of a
lap-shoulder belt, or by the LATCH system.
See Lower Anchors and Tethers for Children
(LATCH System) 081 for more information.
Never use a seat belt extender when
installing a child restraint. Never use
non-regulated aftermarket anchors or
attachments to secure a child restraint.
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 following:
.Instruction labels provided on the child
restraint
.Instruction manual provided with the
child restraint
.This vehicle owner's 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 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 availability in Canada,
check with Transport Canada or the
Provincial Ministry of Transportation office.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
80 Seats and Restraints
Securing the Child Within the Child
Restraint
{Warning
A child can be seriously injured or killed
in a crash if the child is not properly
secured in the child restraint. Secure the
child properly following the instructions
that came with that child restraint.
Where to Put the Restraint
According to accident statistics, children and
infants are safer when properly restrained in
an appropriate child restraint secured in a
rear seating position.
Whenever possible, children aged 12 and
under should be secured in a rear seating
position.
Never put a rear-facing child restraint in the
front. This is because the risk to the
rear-facing child is so great if the airbag
deploys.
{Warning
A child in a rear-facing child restraint can
be seriously injured or killed if the front
passenger 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 front passenger airbag inflates and
the passenger seat is in a forward
position.
Even if the passenger sensing system has
turned off the front passenger frontal
airbag, no system is fail-safe. No one can
guarantee that an airbag will not deploy
under some unusual circumstance, even
though it is turned off.
Secure rear-facing child restraints in a
rear seat, even if the airbag is off. If you
secure a forward-facing child restraint in
the front seat, always move the front
passenger seat as far back as it will go.
It is better to secure the child restraint in
a rear seat.
SeePassenger Sensing System 069 for
additional information.
{Warning
A child in a child restraint in the center
front seat can be badly injured or killed
by the frontal airbags if they inflate.
Never secure a child restraint in the
center front seat. It is always better to
secure a child restraint in a rear seat.
Do not use child restraints in the center
front seat position.
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.
When securing a child restraint with the
seat belts in a rear seat position, study the
instructions that came with the child
restraint to make sure it is compatible with
this vehicle.
Child restraints and booster seats vary
considerably in size, and some may fit in
certain seating positions better than others.
Do not install a child restraint in any rear
seating position where it cannot be installed
securely.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Seats and Restraints 81
Depending on where you place the child
restraint and the size of the child restraint,
you may not be able to access adjacent seat
belts or LATCH anchors for additional
passengers or child restraints. Adjacent
seating positions should not be used if the
child restraint prevents access to or
interferes with the routing of the seat belt.
Adjust the seat in front of a child restraint
to ensure proper installation according to
the child restraint manual. Move the front
seat forward to avoid contact between the
child restraint and the seat or any
accessories mounted to the seat.
Wherever a child restraint is installed, be
sure to follow the instructions that came
with the child restraint and secure the child
restraint properly.
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.Lower Anchors and Tethers for
Children (LATCH System)
The LATCH system secures a child restraint
during driving or in a crash. LATCH
attachments on the child restraint are used
to attach the child restraint to the anchors
in the vehicle. This system is designed to
make installation of a child restraint easier.
In order to use the LATCH system in your
vehicle, you need a child restraint that has
LATCH attachments. LATCH-compatible
rear-facing and forward-facing child seats can
be properly installed using either the LATCH
anchors or the vehicle’s seat belts. Do not
use both the seat belts and the LATCH
anchorage system to secure a rear-facing or
forward-facing child restraint.
Booster seats use the vehicle’s seat belts to
secure the child and the booster seat. If the
manufacturer recommends that the booster
seat be secured with the LATCH system, this
can be done as long as the booster seat can
be positioned properly and there is no
interference with the proper positioning of
the lap-shoulder belt on the child. Make sure to follow the instructions that
came with the child restraint, and also the
instructions in this manual.
When installing a child restraint with a top
tether, you must also use either the lower
anchors or the seat belts to properly secure
the child restraint. A child restraint must
never be installed using only the top tether.
For a forward-facing 5-pt harness child
restraint where the combined weight of the
child and restraint are up to 29.5 kg (65 lb),
use either the lower LATCH anchorages with
the top tether anchorage, or the seat belt
with the top tether anchorage. Where the
combined weight of the child and restraint
are greater than 29.5 kg (65 lb), use the seat
belt with the top tether anchorage only.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
82 Seats and Restraints
Recommended Methods for Attaching Child Restraints
Restraint Type Combined Weight ofthe Child + Child
Restraint Use Only Approved Attachment Methods Shown with an X
LATCH
–Lower
Anchors Only Seat Belt Only LATCH
–Lower
Anchors and Top
Tether Anchor Seat Belt and Top
Tether Anchor
Rear-Facing Child
Restraint Up to 29.5 kg (65 lb)
X X
Rear-Facing Child
Restraint Greater than
29.5 kg (65 lb) X
Forward-Facing Child
Restraint Up to 29.5 kg (65 lb)
X X
Forward-Facing Child
Restraint Greater than
29.5 kg (65 lb) X
See Securing Child Restraints (With the Seat
Belt in the Center Front Seat) 092 or
Securing Child Restraints (With the Seat Belt
in the Rear Seat) 092 or
Securing Child Restraints (With the Seat Belt
in the Front Passenger Seat) 095. Child restraints built after March 2014 are
labeled with the maximum child weight,
with which the LATCH system can be used
for installing the child restraint.
The following explains how to attach a child
restraint with these attachments in the
vehicle. Not all vehicle seating positions have lower
anchors. In this case, the seat belt must be
used (with top tether where available) to
secure the child restraint. See
Securing Child
Restraints (With the Seat Belt in the Center
Front Seat) 092 or
Securing Child Restraints (With the Seat Belt
in the Rear Seat) 092 or
Securing Child Restraints (With the Seat Belt
in the Front Passenger Seat) 095.