2020 GMC SIERRA On star

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Keys, Doors, and Windows 25
A maximum of two remote starts,
or a single start with an extension,
is allowed between ignition cycles.
The vehicle's ignition must be
turned on and then back off to use
remote start again.
Canceling a Remote Start
To cancel a remote start, do one of
the following:
.Press and hold
/until the
parking lamps turn off.
. Turn on the hazard warning
flashers.
. Turn the ignition on and then off.
Door Locks
{Warning
Unlocked doors can be
dangerous.
. Passengers, especially
children, can easily open
the doors and fall out of a
moving vehicle. The doors
(Continued)
Warning (Continued)
can be unlocked and
opened while the vehicle is
moving. The chance of
being thrown out of the
vehicle in a crash is
increased if the doors are
not locked. So, all
passengers should wear
seat belts properly and the
doors should be locked
whenever the vehicle is
driven.
. Young children who get into
unlocked vehicles may be
unable to get out. A child
can be overcome by
extreme heat and can suffer
permanent injuries or even
death from heat stroke.
Always lock the vehicle
whenever leaving it.
. Outsiders can easily enter
through an unlocked door
when you slow down or stop
(Continued)
Warning (Continued)
the vehicle. Locking the
doors can help prevent this
from happening.
There are several ways to lock and
unlock the vehicle.
From outside:
. Use the Remote Keyless Entry
(RKE) transmitter.
. Use Keyless Access,
if equipped.
. Use the key in the driver door or
the passenger door, if equipped.
From inside, use the power door
locks or the manual door locks. To
lock the door with the manual door
locks, push down on the manual
lock knob.
From inside, pull the door handle
once to unlock the door. Pull the
handle again to open the door.
See Vehicle Alarm System 037.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Keys, Doors, and Windows 31
power close. Power opening is still
enabled. See your dealer for
service.
The power tailgate may be
temporarily disabled after repeated
power cycling over a short period of
time. If this occurs, the tailgate can
still be operated manually.
The vehicle must be in P (Park) to
operate the power tailgate. If the
vehicle is shifted out of P (Park)
while the power function is in
progress, the tailgate will continue
to completion. If the vehicle is
accelerated while the tailgate is still
closing, the tailgate may stop and
reverse direction. Make sure the
tailgate is closed and latched before
driving.Lift-to-Close Operation
To close the tailgate using the
lift-to-close feature, lift the tailgate
from the full-open position to at least
10 cm (4 in) and hold it momentarily.
Then, the tailgate will start closing
automatically. If the tailgate is lifted
more than halfway between open
and close, then it will not close
automatically.
Obstacle Detection
If the tailgate encounters an
obstacle during a power open cycle,
it will stop on the obstacle. After
removing the obstruction, the
tailgate can be allowed to open.If the tailgate encounters an
obstacle during the closing cycle, it
will stop and reverse to full open.
If the tailgate encounters multiple
obstacles, the power function will
deactivate. After removing the
obstructions, manually close the
tailgate to resume normal power
operation.
Manual Operation
The tailgate can be manually closed
from the full-open position when the
tailgate is lifted in a continuous
motion. If the tailgate motion is
stopped between the full-open and
half-closed positions, the lift-to-close
feature can engage and power
close the tailgate. If the touch pad is
pressed during power operation, the
tailgate will stop and allow manual
operation. The tailgate must be held
after stopping, or it will continue
to open.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
36 Keys, Doors, and Windows
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 same side to complete the motion.
If the obstruction is not cleared, the
assist steps remain extended.
Slight movement of the steps while
extended is normal.
Kick Switch
1. Place the vehicle in P (Park)
and unlock the doors.
2. Kick the switch to extend the power assist step to the tire.
A Driver Information Center
(DIC) message displays.
3. Kick the switch again to return to normal operation.
Center Stack Switch
The power assist steps can be
extended to the tire by pressing
j.
When extending the steps with
j,
the kick switch is disabled. The
vehicle must be in P (Park) or
N (Neutral).
To extend the steps:
. Press
jto extend both steps.
A DIC message displays.
. Press
jagain to extend to the
tire. A DIC message displays.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
38 Keys, Doors, and Windows
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. .
Always unlock a door with the
RKE transmitter.
Unlocking the driver door with
the key will not disarm the
system or turn off the alarm.
How to Detect a Tamper
Condition
IfKis pressed on the RKE
transmitter and the horn chirps three
times, an alarm occurred previously
while the alarm system was armed.
If the alarm has been activated, a
message will appear on the DIC.
Steering Column Lock
If equipped, the steering column
lock is a theft-deterrent device. This
feature locks the steering column
when the vehicle is turned off and
the driver door is opened, or when
the driver door is opened and then
the vehicle is turned off. The
steering column unlocks when the
vehicle is turned on.
The Driver Information Center (DIC)
may display one of these
messages: .
A message to service the
steering column lock indicates
that an issue has been detected
with the column lock feature and
the vehicle should be serviced.
. A message that the steering
column is locked indicates that
the engine is running, but the
steering column is still locked.
It is normal for the column to be
locked during a remote start, but
the column should unlock after
the brake pedal is pressed and
the vehicle is started. No
message will display during a
remote start.
. A message that the steering
wheel must be turned and the
vehicle must be started again
indicates that the column lock
mechanism is bound, the column
locking device was unable to
unlock the steering column, and
the vehicle did not start. If this
happens, immediately turn the
steering wheel from side to side
to unbind the column lock. If this
does not unlock the steering
column, turn the vehicle off and

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Keys, Doors, and Windows 39
open the driver door to reset the
system. Then turn the vehicle on
and immediately turn the
steering wheel side to side for
about 15 seconds. In some
cases, it may take significant
force to unbind the column.
To keep the steering column from
binding, straighten the front wheels
before turning off the vehicle.
Immobilizer
See Radio Frequency Statement
0 472.
Immobilizer Operation
This vehicle has a passive
theft-deterrent system.
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 tobe 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 15.
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

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
40 Keys, Doors, and Windows
Transmitters to the Vehicle" under
Remote Keyless Entry (RKE)
System Operation (Key Access)
013 or
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
0 15
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
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 (Key Access) 09or
Keys (Keyless Access) 012. 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.
Standard Mirrors
The passenger side mirror is convex
shaped. A convex mirror's surface is
curved so more can be seen from
the driver seat.
Trailer-Tow Mirrors
The upper portion of both the driver
and passenger mirrors is flat.
The lower portion of both the driver
and passenger mirrors is convex.
A convex mirror ’s surface is curved

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
44 Keys, Doors, and Windows
1. Pressgto fold the mirrors in
to the folded position.
2. Press
gagain to fold the
mirrors out to the driving
position.
Resetting the Power Folding
Mirrors
Reset the power folding mirrors if:
. The mirrors are accidentally
obstructed while folding.
. The mirrors are accidentally
manually folded/unfolded.
. The mirrors will not stay in the
unfolded position.
. The mirrors vibrate at normal
driving speeds.
Manually fold both mirrors if they
are out of sync. Fold and unfold the
mirrors three times using the mirror
controls to reset them to their
normal position. A popping noise
may be heard. This sound is normal
after a manual folding operation.
Remote Mirror Folding
If equipped, press and holdQon
the RKE transmitter for
approximately one second to
remotely fold the exterior mirrors.
Press and hold
Kon the RKE
transmitter for approximately
one second to unfold. See Remote
Keyless Entry (RKE) System
Operation (Key Access) 013 or
Remote Keyless Entry (RKE)
System Operation (Keyless Access)
0 15.
This feature can be turned on or off.
See Vehicle Personalization 0157.
Heated Mirrors
If equipped with heated mirrors:
1REAR : Press to heat the
outside mirrors.
See “Rear Window Defogger” under
Dual Automatic Climate Control
System 0179.
Automatic Dimming
Mirror
If equipped, the driver outside mirror
automatically adjusts for the glare of
the headlamps from behind. This
feature comes on when the vehicle
is started.
Blind Spot Mirrors
If equipped, there is a small convex
mirror built into the upper and outer
corner of the driver outside mirror.
It can show objects that may be in
the vehicle's blind zone.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
46 Keys, Doors, and Windows
Interior Mirrors
Interior Rearview Mirrors
Adjust the rearview mirror for a clear
view of the area behind your
vehicle.
Do not spray glass cleaner directly
on the mirror. Use a soft towel
dampened with water.
Manual Rearview Mirror
If equipped, push the tab forward for
daytime use and pull it rearward for
nighttime use to avoid glare from
the headlamps from behind.
Automatic Dimming
Rearview Mirror
If equipped, the mirror will
automatically reduce the glare of the
headlamps from behind. The
dimming feature comes on each
time the vehicle is started.
Rear Camera Mirror
If equipped, this automatic dimming
mirror provides a wide angle camera
view of the area behind the vehicle.
Pull the tab to turn on the display.
Push the tab to turn it off. When off
the mirror is automatic dimming.
Adjust the mirror for a clear view of
the area behind the vehicle while
the display is off.
PressVto scroll through the
adjustment options.
Press
tanduto adjust the
settings using the indicators on the
mirror. The indicators will remain
visible for five seconds after the last
button activation, and the settings
will remain saved.
The adjustment options are: