2018 GMC YUKON ECU

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
62 Seats and Restraints
Seats and
Restraints
Head Restraints
Head Restraints . . . . . . . . . . . . . . . 63
Front Seats
Power Seat Adjustment . . . . . . . . 64
Lumbar Adjustment . . . . . . . . . . . . 65
Reclining Seatbacks . . . . . . . . . . . 65
Memory Seats . . . . . . . . . . . . . . . . . 66
Heated and Ventilated FrontSeats . . . . . . . . . . . . . . . . . . . . . . . . . 69
Rear Seats
Rear Seats . . . . . . . . . . . . . . . . . . . . 70
Heated Rear Seats (IfEquipped) . . . . . . . . . . . . . . . . . . . . 71
Second Row Seats . . . . . . . . . . . . 71
Third Row Seats . . . . . . . . . . . . . . . 76
Seat Belts
Seat Belts . . . . . . . . . . . . . . . . . . . . . 78
How to Wear Seat Belts Properly . . . . . . . . . . . . . . . . . . . . . . 79
Lap-Shoulder Belt . . . . . . . . . . . . . 80
Seat Belt Use During Pregnancy . . . . . . . . . . . . . . . . . . . . 84
Lap Belt . . . . . . . . . . . . . . . . . . . . . . . 85 Seat Belt Extender . . . . . . . . . . . . . 85
Safety System Check . . . . . . . . . . 85
Seat Belt Care . . . . . . . . . . . . . . . . . 86
Replacing Seat Belt System
Parts after a Crash . . . . . . . . . . . 86
Airbag System
Airbag System . . . . . . . . . . . . . . . . . 87
Where Are the Airbags? . . . . . . . 89
When Should an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . . 90
What Makes an Airbag Inflate? . . . . . . . . . . . . . . . . . . . . . . . 91
How Does an Airbag Restrain? . . . . . . . . . . . . . . . . . . . . . 92
What Will You See after an Airbag Inflates? . . . . . . . . . . . . . . 92
Passenger Sensing System . . . 93
Servicing the Airbag-Equipped Vehicle . . . . . . . . . . . . . . . . . . . . . . . 98
Adding Equipment to the Airbag-Equipped Vehicle . . . . . 98
Airbag System Check . . . . . . . . . . 99
Replacing Airbag System Parts after a Crash . . . . . . . . . . . . . . . . . 99
Child Restraints
Older Children . . . . . . . . . . . . . . . . 100
Infants and Young Children . . . 101
Child Restraint Systems . . . . . . 104
Where to Put the Restraint . . . 105 Lower Anchors and Tethers for
Children (LATCH System) . . . 107
Replacing LATCH System Parts After a Crash . . . . . . . . . . 115
Securing Child Restraints (With
the Seat Belt in the
Rear Seat) . . . . . . . . . . . . . . . . . . 115
Securing Child Restraints (With the Seat Belt in the Center
Front Seat) . . . . . . . . . . . . . . . . . . 117
Securing Child Restraints (With the Seat Belt in the Front
Passenger Seat) . . . . . . . . . . . . 118

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
64 Seats and Restraints
Second Row Seats
The vehicle's second row seats
have head restraints in the outboard
seating positions that cannot be
adjusted.
The second row seat outboard head
restraints are not removable.
Third Row Seats
The third row seat head restraint
can be lowered to allow for better
visibility when the rear seat is
unoccupied.To lower the head restraint, press
the button located on the top of the
seatback and push the head
restraint down.
Return the lowered head restraint to
the upright position until it locks into
place. Push and pull on the head
restraint to make sure it is locked.
If you are installing a child restraint
in the third row seat, see
“Securing
a Child Restraint Designed for the
LATCH System” underLower
Anchors and Tethers for Children
(LATCH System) 0107.
Front Seats
Power 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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
76 Seats and Restraints
To return the seat to the sitting
position from the tumbled position:1. Pull the seat down until both sides of the seat are latched to
the floor. Make sure the seat is
securely latched to the floor
before raising the seatback.
If both sides are not latched to
the floor, the seatback will not
raise.
2. Lift the seatback and push it rearward. Push and pull on the
seatback to make sure it is
locked.
Third Row Seats
Folding the Seatback
Caution
Folding a rear seat with the seat
belts still fastened may cause
damage to the seat or the seat
belts. Always unbuckle the seat
belts and return them to their
normal stowed position before
folding a rear seat. The transmission must be in
P (Park) for this feature to work.
The third row seatbacks can be
folded to increase cargo space.
1. If equipped, Second Row
Power Seat Fold and
Tumble Switches
2. If equipped, Third Row Power Seat Fold and Raise
Switches
To fold the seatback:
1. Open the liftgate to access the controls for the third row seat. 2. Make sure that there is nothing
under, in front of, or on
the seat.
3. Fully lower the head restraints. See Head Restraints 063. Put
the second row seatback in the
upright position. See Second
Row Seats 071.
4. Disconnect the rear seat belt
mini-latch, using a key in the
slot on the mini-buckle, and let
the belt retract into the
headliner.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Seats and Restraints 77
5. Stow the mini-latch in theholder in the headliner.
6. Press and hold the switch (2) on the side trim of the cargo
area to fold the third row
seatback.
The left switch folds the left
seatback, and the right switch
folds the right seatback.
7. Repeat the steps for the other seatback, if desired.
The switches (1) can be used to fold
or fold and tumble the second row
seats from the cargo area. See
Second Row Seats 071.
Returning the Third Row
Seatback to the Upright
Position
1. Second Row Power Seat
Fold and Tumble Switches
2. Third Row Power Seat Fold and Raise Switches
To return the third row seatback to
the upright position:
1. Open the liftgate to access the controls for the seat.
2. Press and hold the switch (2) on the side trim of the cargo
area to raise the third row
seatback. The left switch raises the left
seatback, and the right switch
raises the right seatback.
{Warning
A seat belt that is improperly
routed, not properly attached,
or twisted will not provide the
protection needed in a crash. The
person wearing the belt could be
seriously injured. After raising the
rear seatback, always check to be
sure that the seat belts are
properly routed and attached, and
are not twisted.
3. Reconnect the center seat belt mini-latch to the mini-buckle.
Do not let it twist.
4. Pull on the seat belt to be sure the mini-latch is secure.
5. Repeat the steps for the other seatback, if desired.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Seats and Restraints 81
3. Push the latch plate into thebuckle until it clicks. If the latch
plate will not go fully into the
buckle, check if the correct
buckle is being used.
Pull up on the latch plate to
make sure it is secure. If the
belt is not long enough, see
Seat Belt Extender 085.
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”
in this section for instructions
on use and important safety
information.
5. To make the lap part tight, pull
up on the shoulder belt.
For third row seats, it may be
necessary to pull stitching on
the seat belt through the latch
plate to fully tighten the lap belt
on smaller occupants.
To unlatch the belt, push the button
on the buckle. The belt should
return to its stowed position.
For third row seats, slide the latch
plate up the safety webbing when
the seat belt is not in use. The latch
plate should rest on the stitching on
the seat belt.
Always stow the seat belt slowly.
If the seat belt webbing returns
quickly to the stowed position, the
retractor may lock and cannot be
pulled out. If this happens, pull the
seat belt straight out firmly to unlock
the webbing, and then release it.
If the webbing is still locked in the
retractor, see your dealer.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
Seats and Restraints 85
Lap Belt
This section is only for the lap belt.
To learn how to wear a lap-shoulder
belt, seeLap-Shoulder Belt 080.
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 085.
Make sure the release button on the
buckle is positioned so you would
be able to unbuckle the seat belt
quickly if necessary.
If you find that the latch plate will
not go fully into the buckle, see if
you are using the correct buckle. Be
sure that the latch plate clicks when
inserted into the buckle.
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

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
88 Seats and Restraints
{Warning
Because airbags inflate with great
force and faster than the blink of
an eye, anyone who is up
against, or very close to any
airbag when it inflates can be
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.(Continued)
Warning (Continued)
Occupants should not lean on or
sleep against the front center
armrest or console in vehicles
with a front center airbag.
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 0100 or
Infants and Young Children
0 101.
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 0144.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - CRC - 11/3/17
90 Seats and Restraints
Driver Side Shown, PassengerSide Similar
The roof-rail airbags for the driver,
front outboard passenger, and
second and third row outboard
seating positions are in the ceiling
above the side windows.
{Warning
If something is between an
occupant and an airbag, the
airbag might not inflate properly
or it might force the object into
that person causing severe injury (Continued)
Warning (Continued)
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 or console
accessories that block the
inflation path of a seat-mounted
side impact airbag or the front
center airbag, if equipped.
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 087.
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 that 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.