2020 GMC SIERRA DENALI ECU

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Keys, Doors, and Windows 9
Keys, Doors, and
Windows
Keys and Locks
Keys (Key Access) . . . . . . . . . . . . . . 9
Keys (Keyless Access) . . . . . . . . 12
Remote Keyless Entry (RKE)System . . . . . . . . . . . . . . . . . . . . . . . 13
Remote Keyless Entry (RKE) System Operation (Key
Access) . . . . . . . . . . . . . . . . . . . . . . 13
Remote Keyless Entry (RKE) System Operation (Keyless
Access) . . . . . . . . . . . . . . . . . . . . . . 16
Remote Vehicle Start . . . . . . . . . . 25
Door Locks . . . . . . . . . . . . . . . . . . . . 26
Power Door Locks . . . . . . . . . . . . . 27
Delayed Locking . . . . . . . . . . . . . . . 27
Automatic Door Locks . . . . . . . . . 27
Lockout Protection . . . . . . . . . . . . . 28
Safety Locks . . . . . . . . . . . . . . . . . . . 28
Doors
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . 29
Power Assist Steps . . . . . . . . . . . . 34
Vehicle Security
Vehicle Security . . . . . . . . . . . . . . . . 36
Vehicle Alarm System . . . . . . . . . 36 Steering Column Lock . . . . . . . . . 37
Immobilizer . . . . . . . . . . . . . . . . . . . . 37
Immobilizer Operation . . . . . . . . . 37
Exterior Mirrors
Convex Mirrors . . . . . . . . . . . . . . . . 39
Manual Mirrors . . . . . . . . . . . . . . . . . 39
Trailer-Tow Mirrors . . . . . . . . . . . . . 40
Power Mirrors . . . . . . . . . . . . . . . . . . 41
Folding Mirrors . . . . . . . . . . . . . . . . . 42
Heated Mirrors . . . . . . . . . . . . . . . . . 43
Automatic Dimming Mirror . . . . . 43
Blind Spot Mirrors . . . . . . . . . . . . . . 43
Reverse Tilt Mirrors . . . . . . . . . . . . 44
Interior Mirrors
Interior Rearview Mirrors . . . . . . . 44
Manual Rearview Mirror . . . . . . . . 44
Automatic Dimming Rearview
Mirror . . . . . . . . . . . . . . . . . . . . . . . . . 44
Rear Camera Mirror . . . . . . . . . . . . 45
Windows
Windows . . . . . . . . . . . . . . . . . . . . . . . 47
Manual Windows . . . . . . . . . . . . . . 47
Power Windows . . . . . . . . . . . . . . . 47
Rear Windows . . . . . . . . . . . . . . . . . 49
Sun Visors . . . . . . . . . . . . . . . . . . . . . 50
Roof
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . 50
Keys and Locks
Keys (Key Access)
{Warning
Leaving children in a vehicle with
the ignition key is dangerous and
children or others could be
seriously injured or killed. They
could operate the power windows
or other controls or make the
vehicle move. The windows will
function with the keys in the
ignition, and children or others
could be caught in the path of a
closing window. Do not leave
children in a vehicle with the
ignition key.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Keys, Doors, and Windows 11
Interference from radio-frequency
identification (RFID) tags may
prevent the key from starting the
vehicle. Keep RFID tags away from
the key when starting the vehicle.
The key is used for the ignition, all
door locks, and the glove box.
If equipped with memory seats,
keys 1 and 2 are linked to seating
positions of memory 1 or 2. See
Memory Seats058.
Programming Keys
Follow these procedures to program
up to eight keys to the vehicle. Programming with Two
Recognized Keys
To program a new key:
1. Insert the original, already programmed key in the ignition
and turn the ignition on.
2. Turn the ignition off, and remove the key.
3. Quickly, within five seconds, insert the second original
already programmed key in the
ignition and turn the ignition on.
4. Turn the ignition off, and remove the key.
5. Insert the key to be programmed and turn the
ignition on within five seconds.
6. After a few seconds, the security light will turn off once
the key has been programmed.
7. Repeat Steps 1–5 if additional keys are to be programmed.
If a key is lost or damaged, see your
dealer to have a new key made. Programming without
Recognized Keys
Program a new key to the vehicle
when a recognized key is not
available. Canadian regulations
require that owners see their dealer.
If two currently recognized keys are
not available, follow this procedure
to program the first key.
This procedure will take
approximately 30 minutes to
complete for the first key. The
vehicle must be off and all of the
keys you wish to program must be
with you.
1. Insert the new vehicle key into the ignition.
2. Turn the ignition on. The security light will come on.
3. Wait 10 minutes until the security light turns off.
4. Turn the ignition off.
5. Repeat Steps 2–4 two more times. After the third time, turn
the ignition on; the key is

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Keys, Doors, and Windows 29
To open a rear door when the safety
lock is on:1. Unlock the door by activating the inside handle, by pressing
the power door unlock switch,
or by using the Remote
Keyless Entry (RKE)
transmitter.
2. Open the door from the outside.
When the safety lock is enabled,
adults and older children will not be
able to open the rear door from the
inside. Cancel the safety locks to
enable the doors to open from the
inside.
To cancel the safety lock: 1. Unlock the door and open it from the outside.
2. Move the lever up to unlock. Do the same for the other door.Doors
Tailgate
Manual Tailgate
{Warning
It is extremely dangerous to ride
on the tailgate, even when the
vehicle is operated at low speeds.
People riding on the tailgate can
easily lose their balance and fall
in response to vehicle
maneuvers. Falling from a moving
vehicle may result in serious
injuries or death. Do not allow
people to ride on the tailgate. Be
sure everyone in your vehicle is in
a seat and using a seat belt
properly.
Use the key to unlock the tailgate.
Open the tailgate by lifting up on its
handle while pulling the
tailgate down.
To shut the tailgate, firmly push it
upward until it latches. After closing the tailgate, pull it back
to be sure it is latched securely.
Some tailgates have an electric
latch. If the battery is disconnected
or has low voltage, the tailgate will
not open. The tailgate will resume
operation when the battery is
reconnected or recharged.Power Release Tailgate
{Warning
Make sure there is no one in the
way of the power tailgate as it is
opening and closing, and keep
hands away from the tailgate
hinges when in use. You or others
could be injured if caught in the
path of the power tailgate or
tailgate hinges.
Caution
To avoid damage to the tailgate,
make sure the area behind the
tailgate is clear before opening it.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
30 Keys, Doors, and Windows
In the case of a dead battery, the
tailgate can be opened manually.
Contact your dealer or Roadside
Assistance.
If equipped, to lock or unlock the
tailgate, use the RKE transmitter or
the key. SeeRemote Keyless Entry
(RKE) System Operation (Key
Access) 013 or
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
0 16.
The vehicle must be in P (Park).
To open the tailgate:
. Press
xtwice quickly on the
RKE transmitter until the tailgate
moves.
. Press5on the center stack.
.
Press the touch pad on the
tailgate handle after unlocking all
doors. Use the top of the tailgate
to pull against if assistance is
required. If equipped with
Keyless Access, a locked
tailgate can be opened if the
RKE transmitter is within
1 m (3 ft).
To close the tailgate, firmly push it
upward until it latches. Pull it back
to be sure it is latched securely.
MultiPro Tailgate
{Warning
Make sure there is no one in the
way of the power tailgate as it is
opening and closing, and keep
hands away from the tailgate
hinges when in use. You or others
could be injured if caught in the
path of the power tailgate or
tailgate hinges.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Keys, Doors, and Windows 31
Caution
To avoid damage to the tailgate,
make sure the area behind the
tailgate is clear before opening it.
If equipped with this feature, the
vehicle must be in P (Park).
Switches in the inner tailgate
prevent the primary tailgate from
being opened when the inner
tailgate is not fully closed. To open the primary tailgate:
.
Pressxtwice quickly on the
RKE transmitter until the tailgate
moves. See Remote Keyless
Entry (RKE) System Operation
(Key Access) 013 or
Remote Keyless Entry (RKE)
System Operation (Keyless
Access) 016. If equipped with
Keyless Access, the tailgate can
be opened if the RKE transmitter
is within 1 m (3 ft).
. Press5on the center stack.
. Press the lower touch pad on
the tailgate handle after
unlocking all doors. Use the top
of the tailgate to pull against if
assistance is required.
To close the primary tailgate, firmly
push it upward until it latches. Pull it
back to be sure it is latched
securely.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
32 Keys, Doors, and Windows
To open the inner tailgate, press the
upper touch pad on the tailgate
handle after unlocking all doors. Pull
the top of the tailgate to open.
Caution
Do not open the inner tailgate
with the primary tailgate open if
there is a hitch ball or trailer
attached. This may damage the
tailgate.
To close the inner tailgate with the
primary tailgate closed, firmly push
or pull it upward until it latches. Pull
it back to be sure it is latched
securely.
To close the inner tailgate with the
primary tailgate open:
. Hold the primary tailgate and
firmly close the inner tailgate.
. Raise the inner tailgate so it
meets the primary tailgate and
close together at the same time.
When using the tailgate step as a
load stop, the load must be secured
as the load could shift. See Cargo
Tie-Downs 0115.
Tailgate Step
{Warning
To avoid personal injury, keep
hands away from the hinges
when operating the tailgate step.
With the primary and inner tailgates
open, the tailgate step can be
lowered to access the pickup bed.
Using the Step
Caution
When using the tailgate as a step,
the load rating is 170 kg (375 lb),
which includes a person and
cargo. Overloading the tailgate
step can cause damage to the
tailgate system.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
34 Keys, Doors, and Windows
Preferred MethodAlternate Method
When applying any load to the
tailgate, distribute the weight evenly
across the width of the tailgate. This
applies to all tailgate types.
. Use a load-distributing
member (1).
. Secure the ramp to the
bumper (2).
Power Assist Steps
{Warning
To avoid personal injury or
property damage, before entering
or exiting the vehicle, be sure the
power assist step is fully
extended. Do not step on the
power assist step while it is
moving. Never place hands or
other body parts between the
extended power assist step and
the vehicle.
If equipped, the power assist steps,
when enabled, will extend when the
door is opened. They will retract
three seconds after the door is
closed or immediately if the vehicle
starts moving.
Keep hands, children, pets, objects,
and clothing clear of the power
assist steps when in motion.
The steps will reverse direction if
there is an obstruction. If possible,
carefully remove the obstruction,
then open and close the door on the

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
36 Keys, Doors, and Windows
Vehicle Security
This vehicle has theft-deterrent
features; however, they do not make
the vehicle impossible to steal.
Vehicle Alarm System
The indicator light, on the
instrument panel near the
windshield, indicates the status of
the system.
Off :Alarm system is disarmed.
On Solid : Vehicle is secured
during the delay to arm the system. Fast Flash :
Vehicle is unsecured.
A door or the hood is open.
Slow Flash : Alarm system is
armed.
Arming the Alarm System
1. Turn off the vehicle.
2. Lock the vehicle in one of two ways:
.Use the RKE transmitter.
. With a door open, press
Q
on the interior of the door.
3. After 30 seconds, the alarm system will arm and the
indicator light will begin to
slowly flash. Pressing
Qon the
RKE transmitter a second time
will bypass the 30-second
delay and immediately arm the
alarm system.
The vehicle alarm system will not
arm if the doors are locked with
the key.
If the driver door is opened without
first unlocking with the RKE
transmitter, the horn will chirp and the lights will flash to indicate
pre-alarm. If the vehicle is not
started, or the door is not unlocked
by pressing
Kon the RKE
transmitter during the 10-second
pre-alarm, the alarm will be
activated.
The alarm will also be activated if a
passenger door or the hood is
opened without first disarming the
system. When the alarm is
activated, the turn signals flash and
the horn sounds for about
30 seconds. The alarm system will
then re-arm to monitor for the next
unauthorized event.
Disarming the Alarm System
To disarm the alarm system or turn
off the alarm if it has been activated:
. Press
Kon the RKE transmitter.
. Start the vehicle.
To avoid setting off the alarm by
mistake:
. Lock the vehicle after all
occupants have exited.