2020 GMC SIERRA DENALI ECU

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
38 Keys, Doors, and Windows
The system does not have to be
manually armed or disarmed.
The vehicle is automatically
immobilized when the vehicle is
turned off.
The system is automatically
disarmed when the ignition is turned
from off to on.
The security light, in the instrument
cluster, comes on if there is a
problem with arming or disarming
the theft-deterrent system.
The system has one or more RKE
transmitters matched to an
immobilizer control unit in your
vehicle. Only a correctly matched
RKE transmitter will start the
vehicle. If the transmitter is ever
damaged, you may not be able to
start your vehicle.
When trying to start the vehicle, the
security light may come 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 vehicle will not change ignition
modes (ACC/ACCESSORY, on, off),
and the RKE transmitter appears to
be undamaged, try another
transmitter. Or, you may try placing
the transmitter in the transmitter
pocket located in the center
console. See
Remote Keyless Entry
(RKE) System Operation (Key
Access) 013 or
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
0 16.
If the ignition mode will not change
with the other transmitter or with the
transmitter in the transmitter pocket,
your vehicle needs service. If the
ignition does change modes, the
first transmitter may be faulty. See
your dealer who can service the
theft-deterrent system and have a
new RKE transmitter programmed to
the vehicle. It is possible for the immobilizer
system to learn new or replacement
RKE transmitters. Up to eight
transmitters can be programmed for
the vehicle. To program additional
transmitters, see "Programming
Transmitters to the Vehicle" under
Remote Keyless Entry (RKE)
System Operation (Key Access)
0
13 or
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
0 16
Do not leave the transmitter or
device that disarms or deactivates
the vehicle theft system in the
vehicle.
When equipped with a key, 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 Breakers 0370.
If the engine still does not start with
the other key, the vehicle needs

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
52 Seats and Restraints
Seats and
Restraints
Head Restraints
Head Restraints . . . . . . . . . . . . . . . 53
Front Seats
Seat Adjustment . . . . . . . . . . . . . . . 54
Center Seat . . . . . . . . . . . . . . . . . . . . 55
Power Seat Adjustment . . . . . . . . 55
Lumbar Adjustment . . . . . . . . . . . . 56
Reclining Seatbacks . . . . . . . . . . . 56
Memory Seats . . . . . . . . . . . . . . . . . 58
Heated and Ventilated FrontSeats . . . . . . . . . . . . . . . . . . . . . . . . . 60
Rear Seats
Rear Seats . . . . . . . . . . . . . . . . . . . . 62
Heated Rear Seats . . . . . . . . . . . . 63
Seat Belts
Seat Belts . . . . . . . . . . . . . . . . . . . . . 64
How to Wear Seat BeltsProperly . . . . . . . . . . . . . . . . . . . . . . 65
Lap-Shoulder Belt . . . . . . . . . . . . . 67
Seat Belt Use During Pregnancy . . . . . . . . . . . . . . . . . . . . 69
Seat Belt Extender . . . . . . . . . . . . . 70
Safety System Check . . . . . . . . . . 70 Seat Belt Care . . . . . . . . . . . . . . . . . 70
Replacing Seat Belt System
Parts after a Crash . . . . . . . . . . . 71
Airbag System
Airbag System . . . . . . . . . . . . . . . . . 71
Where Are the Airbags? . . . . . . . 73
When Should an AirbagInflate? . . . . . . . . . . . . . . . . . . . . . . . 75
What Makes an Airbag Inflate? . . . . . . . . . . . . . . . . . . . . . . . 75
How Does an Airbag Restrain? . . . . . . . . . . . . . . . . . . . . . 76
What Will You See after an Airbag Inflates? . . . . . . . . . . . . . . 76
Passenger Sensing System . . . 77
Servicing the Airbag-Equipped Vehicle . . . . . . . . . . . . . . . . . . . . . . . 82
Adding Equipment to the Airbag-Equipped Vehicle . . . . . 82
Airbag System Check . . . . . . . . . . 83
Replacing Airbag System Parts after a Crash . . . . . . . . . . . . . . . . . 83
Child Restraints
Older Children . . . . . . . . . . . . . . . . . 84
Infants and Young Children . . . . 86
Child Restraint Systems . . . . . . . 88
Where to Put the Restraint . . . . . 90
Lower Anchors and Tethers forChildren (LATCH System) . . . . 91 Replacing LATCH System
Parts After a Crash . . . . . . . . . 104
Securing Child Restraints (With the Seat Belt in the
Rear Seat) . . . . . . . . . . . . . . . . . . 104
Securing Child Restraints (In the Center Front Seat) . . . . . . 107
Securing Child Restraints (With the Seat Belt in the Front
Outboard Seat) . . . . . . . . . . . . . 108

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
68 Seats and Restraints
feature stays engaged after
letting the belt go back to
stowed position on the seat,
move the seat rearward or
recline the seat until the
shoulder belt retractor lock
releases.
Engaging the child restraint
locking feature in the front
outboard seating position may
affect the passenger sensing
system, if equipped. See
Passenger Sensing System
077.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 070.
Position the release button on
the buckle so that the seat belt
could be quickly unbuckled if
necessary.
4. To make the lap part tight, pull up on the shoulder belt.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
70 Seats and Restraints
A pregnant woman should wear a
lap-shoulder belt, and the lap
portion should be worn as low as
possible, below the rounding,
throughout the pregnancy.
The best way to protect the fetus is
to protect the mother. When a seat
belt is worn properly, it is more likely
that the fetus will not be hurt in a
crash. For pregnant women, as for
anyone, the key to making seat
belts effective is wearing them
properly.
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 moreinformation 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, 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 0135.
Keep seat belts clean and dry. See
Seat Belt Care 070.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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Seats and Restraints 73
{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 084 or
Infants and Young Children 086.
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 0135.
Where Are the Airbags?
The driver frontal airbag is in the
center of the steering wheel.
The front outboard passenger
frontal airbag is in the passenger
side instrument panel.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
74 Seats and Restraints
Driver Side Shown, PassengerSide Similar
The driver and front outboard
passenger seat-mounted side
impact airbags are in the side of the
seatbacks closest to the door.Driver Side Crew Cab Shown, Passenger Side Double and Regular Cabs Similar
The roof-rail airbags for the driver,
front outboard passenger, and
second row outboard passengers
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 (Continued)
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
78 Seats and Restraints
United States
Canada
The words ON and OFF, or the
symbols 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 0136.
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)
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)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Seats and Restraints 79
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 0136.
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 0135 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.