2019 GMC YUKON ECU

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-12460267) - 2019 - crc - 9/11/18
56 Keys, Doors, and Windows
When trying to start the vehicle, the
security light comes on briefly when
the ignition is turned on.
If the engine does not start and the
security light stays on, there is a
problem with the system. Turn the
ignition off and try again.
If the engine still does not start, and
the key appears to be undamaged,
try another ignition key. It may be
necessary to check the fuse. See
Fuses and Circuit Breakers0329.
If the engine still does not start with
the other key, the vehicle needs
service. If the vehicle does start, the
first key may be faulty. See your
dealer. It is possible for the immobilizer
system to learn new or replacement
keys. Up to eight keys can be
programmed for the vehicle. To
program additional keys, see
Keys
(Keyless Access) 029 orKeys (Key
Access) 030. To program additional
transmitters, see your dealer.
Do not leave the key or device that
disarms or deactivates the vehicle
theft system in the vehicle.
See your dealer to get a new key
blank cut exactly as the ignition key
that operates the system.Exterior Mirrors
Convex Mirrors
{Warning
A convex mirror can make things,
like other vehicles, look farther
away than they really are. If you
cut too sharply into the right lane,
you could hit a vehicle on the
right. Check the inside mirror or
glance over your shoulder before
changing lanes.
The passenger side mirror is convex
shaped. A convex mirror's surface is
curved so more can be seen from
the driver seat.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-12460267) - 2019 - crc - 9/11/18
Seats and Restraints 65
Seats and
Restraints
Head Restraints
Head Restraints . . . . . . . . . . . . . . . 66
Front Seats
Center Seat . . . . . . . . . . . . . . . . . . . . 67
Power Seat Adjustment . . . . . . . . 67
Lumbar Adjustment . . . . . . . . . . . . 68
Reclining Seatbacks . . . . . . . . . . . 69
Memory Seats . . . . . . . . . . . . . . . . . 69
Heated and Ventilated FrontSeats . . . . . . . . . . . . . . . . . . . . . . . . . 72
Rear Seats
Rear Seats . . . . . . . . . . . . . . . . . . . . 74
Heated Rear Seats (IfEquipped) . . . . . . . . . . . . . . . . . . . . 74
Second Row Seats . . . . . . . . . . . . 75
Third Row Seats . . . . . . . . . . . . . . . 79
Seat Belts
Seat Belts . . . . . . . . . . . . . . . . . . . . . 81
How to Wear Seat Belts Properly . . . . . . . . . . . . . . . . . . . . . . 82
Lap-Shoulder Belt . . . . . . . . . . . . . 84
Seat Belt Use During Pregnancy . . . . . . . . . . . . . . . . . . . . 88 Lap Belt . . . . . . . . . . . . . . . . . . . . . . . 89
Seat Belt Extender . . . . . . . . . . . . . 90
Safety System Check . . . . . . . . . . 90
Seat Belt Care . . . . . . . . . . . . . . . . . 90
Replacing Seat Belt System
Parts after a Crash . . . . . . . . . . . 91
Airbag System
Airbag System . . . . . . . . . . . . . . . . . 91
Where Are the Airbags? . . . . . . . 93
When Should an AirbagInflate? . . . . . . . . . . . . . . . . . . . . . . . 95
What Makes an Airbag Inflate? . . . . . . . . . . . . . . . . . . . . . . . 96
How Does an Airbag Restrain? . . . . . . . . . . . . . . . . . . . . . 96
What Will You See after an
Airbag Inflates? . . . . . . . . . . . . . . 97
Passenger Sensing System . . . 98
Servicing the Airbag-Equipped Vehicle . . . . . . . . . . . . . . . . . . . . . . 102
Adding Equipment to the Airbag-Equipped Vehicle . . . . 103
Airbag System Check . . . . . . . . 104
Replacing Airbag System Parts after a Crash . . . . . . . . . . . . . . . . 104
Child Restraints
Older Children . . . . . . . . . . . . . . . . 104
Infants and Young Children . . . 106
Child Restraint Systems . . . . . . 108 Where to Put the Restraint . . . . 110
Lower Anchors and Tethers for
Children (LATCH System) . . . 111
Replacing LATCH System Parts After a Crash . . . . . . . . . 120
Securing Child Restraints (With the Seat Belt in the
Rear Seat) . . . . . . . . . . . . . . . . . . 120
Securing Child Restraints (With the Seat Belt in the Center
Front Seat) . . . . . . . . . . . . . . . . . . 122
Securing Child Restraints (With the Seat Belt in the Front
Passenger Seat) . . . . . . . . . . . . 123

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-12460267) - 2019 - crc - 9/11/18
Seats and Restraints 67
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) 0111.
Front Seats
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.
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-12460267) - 2019 - crc - 9/11/18
Seats and Restraints 79
The left switch folds the left
seatback, and the right switch
folds the right seatback.
3. Press the switch again to release the rear of the seat
from the floor. The seat will
tumble forward.
The switches (2) can be used to fold
and unfold the third row seatbacks
from the cargo area. See Third Row
Seats 079.
Returning the Seat to the
Sitting Position
{Warning
If either seatback is not locked, it
could move forward in a sudden
stop or crash. That could cause
injury to the person sitting there.
Always push and pull on the
seatbacks to be sure they are
locked. 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. Second Row Power Seat
Fold and Tumble Switches,
if equipped.
2. Third Row Power Seat Fold and Raise Switches,
if equipped.
To fold the seatback:
1. Open the liftgate to access the controls for the third row seat.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-12460267) - 2019 - crc - 9/11/18
Seats and Restraints 81
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.
Seat Belts
This section describes how to use
seat belts properly, and some things
not to do.
{Warning
Do not let anyone ride where a
seat belt cannot be worn properly.
In a crash, if you or your
passenger(s) are not wearing
seat belts, injuries can be much
worse than if you are wearing
seat belts. You can be seriously
injured or killed by hitting things
inside the vehicle harder or by
being ejected from the vehicle. In
addition, anyone who is not
buckled up can strike other
passengers in the vehicle.
It is extremely dangerous to ride
in a cargo area, inside or outside
of a vehicle. In a collision,
passengers riding in these areas
are more likely to be seriously
injured or killed. Do not allow
(Continued)
Warning (Continued)
passengers to ride in any area of
the vehicle that is not equipped
with seats and seat belts.
Always wear a seat belt, and
check that all passenger(s) are
restrained properly too.
This vehicle has indicators as a
reminder to buckle the seat belts.
See Seat Belt Reminders 0150.
Why Seat Belts Work

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-12460267) - 2019 - crc - 9/11/18
Seats and Restraints 85
Engaging the child restraint
locking feature in the front
outboard seating position may
affect the passenger sensing
system. SeePassenger
Sensing System 098.
For front seating positions,
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. 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 090.
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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-12460267) - 2019 - crc - 9/11/18
90 Seats and Restraints
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 aseat belt system from performing
properly. See your dealer to have it
repaired. Torn, frayed, or twisted
seat belts may not protect you in a
crash. Torn or frayed seat belts can
rip apart under impact forces. If a
belt is torn or frayed, have it
replaced immediately. If a belt is
twisted, it may be possible to
untwist by reversing the latch plate
on the webbing. If the twist cannot
be corrected, ask your dealer to
fix it.
Make sure the seat belt reminder
light is working. See
Seat Belt
Reminders 0150.
Keep seat belts clean and dry. See
Seat Belt Care 090.
Seat Belt Care
Keep belts clean and dry.
Seat belts should be properly cared
for and maintained.
Seat belt hardware should be kept
dry and free of dust or debris. As
necessary, exterior hard surfaces
and seat belt webbing may be lightly
cleaned with mild soap and water. Ensure there is not excessive dust
or debris in the mechanism. If dust
or debris exists in the system please
see the dealer. Parts may need to
be replaced to ensure proper
functionality of the system.
{Warning
Do not bleach or dye seat belt
webbing. It may severely weaken
the webbing. In a crash, they
might not be able to provide
adequate protection. Clean and
rinse seat belt webbing only with
mild soap and lukewarm water.
Allow the webbing to dry.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-12460267) - 2019 - crc - 9/11/18
Seats and Restraints 93
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 0104 or
Infants and Young Children
0 106.
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 0151.
Where Are the Airbags?
The driver frontal airbag is in the
center of the steering wheel.