ECU GMC SIERRA 2018 Owner's Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
In Brief 29
Vehicles with a Center Console
.One or two in front of the
cupholders on the center
console
. One inside the center console
. One on the rear of the center
console
Vehicles with Bench Seats
. One on the center stack below
the climate control system
. One or two in the storage area
on the bench seat
Lift the cover to access and replace
when not in use.
See Power Outlets 0133.Universal Remote System
If equipped with the Universal
Remote system, these buttons will
be in the front overhead console.
This system provides a way to
replace up to three remote control
transmitters used to activate
devices such as garage door
openers, security systems, and
home automation devices.
See Universal Remote System
0 172.
Sunroof
If equipped, the sunroof operates
when the ignition is on or in ACC/
ACCESSORY, or when Retained
Accessory Power (RAP) is active.
See Retained Accessory Power
(RAP) 0260.
Slide Switch
Express-Open/Express-Close : To
express-open the sunroof, fully
press and release
I. Press the
switch again to stop the movement.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
34 Keys, Doors, and Windows
Keys, Doors, and
Windows
Keys and Locks
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Remote Keyless Entry (RKE)System . . . . . . . . . . . . . . . . . . . . . . . 37
Remote Keyless Entry (RKE) System Operation . . . . . . . . . . . . 37
Remote Vehicle Start . . . . . . . . . . 39
Door Locks . . . . . . . . . . . . . . . . . . . . 40
Power Door Locks . . . . . . . . . . . . . 41
Automatic Door Locks . . . . . . . . . 41
Lockout Protection . . . . . . . . . . . . . 42
Safety Locks . . . . . . . . . . . . . . . . . . . 42
Doors
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . 43
Power Assist Steps . . . . . . . . . . . . 43
Vehicle Security
Vehicle Security . . . . . . . . . . . . . . . . 44
Vehicle Alarm System . . . . . . . . . 44
Immobilizer . . . . . . . . . . . . . . . . . . . . 46
Immobilizer Operation . . . . . . . . . 46
Exterior Mirrors
Convex Mirrors . . . . . . . . . . . . . . . . 47
Manual Mirrors . . . . . . . . . . . . . . . . . 47 Trailer-Tow Mirrors . . . . . . . . . . . . . 48
Power Mirrors . . . . . . . . . . . . . . . . . . 48
Folding Mirrors . . . . . . . . . . . . . . . . . 49
Heated Mirrors . . . . . . . . . . . . . . . . . 50
Automatic Dimming Mirror . . . . . 50
Blind Spot Mirrors . . . . . . . . . . . . . . 50
Reverse Tilt Mirrors . . . . . . . . . . . . 51
Interior Mirrors
Interior Rearview Mirrors . . . . . . . 51
Manual Rearview Mirror . . . . . . . . 52
Automatic Dimming Rearview
Mirror . . . . . . . . . . . . . . . . . . . . . . . . . 52
Windows
Windows . . . . . . . . . . . . . . . . . . . . . . . 52
Manual Windows . . . . . . . . . . . . . . 52
Power Windows . . . . . . . . . . . . . . . 52
Rear Windows . . . . . . . . . . . . . . . . . 54
Sun Visors . . . . . . . . . . . . . . . . . . . . . 55
Roof
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . 55
Keys and Locks
Keys
{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-11349177) - 2018 - CRC - 10/17/17
36 Keys, Doors, and Windows
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 glove box,
if equipped.
If equipped with memory seats,
keys 1 and 2 are linked to seating
positions of memory 1 or 2. See
Memory Seats062.
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. 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-11349177) - 2018 - CRC - 10/17/17
Keys, Doors, and Windows 43
Doors
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.
If equipped, to lock or unlock the
tailgate, use the RKE transmitter or
the key. See Remote Keyless Entry
(RKE) System Operation 037.
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 latches securely.
Power Assist Steps
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. 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 DIC message displays.
3. Kick the switch again to return to normal operation.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
44 Keys, Doors, and Windows
Center Stack Switch
The power assist steps
can be extended and
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.
. Press
jagain to return to
normal operation.
Enable/Disable
To enable or disable the power
assist steps, press and hold
jfor
four seconds. A DIC message
displays.
Cleaning
Clean the power assist steps
regularly. For an automatic car
wash, extend the steps while in
N (Neutral) using the center stack
switch. The steps will stow when
shifting into D (Drive).
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Keys, Doors, and Windows 45
Fast Flash :Vehicle is unsecured.
A door, the tailgate, 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, the tailgate, 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
accident:
.
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.
Inclination Sensor and
Intrusion Sensor
In addition to the standard
theft-deterrent system features, this
system may also have an inclination
sensor and intrusion sensor.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
46 Keys, Doors, and Windows
The inclination sensor can set off
the alarm if it senses movement of
the vehicle, such as a change in
vehicle orientation.
The intrusion sensor monitors the
vehicle interior, and can activate the
alarm if it senses unauthorized entry
into the vehicle’s interior. Do not
allow passengers or pets to remain
in the vehicle when the intrusion
sensor is activated.
Before arming the theft-deterrent
system and activating the intrusion
sensor:
.Make sure all doors and
windows are completely closed.
. Secure any loose items such as
sunshades.
. Make sure there are no
obstructions blocking the
sensors in the front overhead
console.
. Close DVD screens, if equipped,
before leaving the vehicle.Inclination and Intrusion
Sensors Disable Switch
It is recommended that the intrusion
and inclination sensors be
deactivated if pets are left in the
vehicle or if the vehicle is being
transported.
With the vehicle turned off, press
oin the front overhead console.
The indicator light will come on
momentarily, indicating that these
sensors have been disabled for the
next alarm system arming cycle.
Immobilizer
See Radio Frequency Statement
0 475.
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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Keys, Doors, and Windows 47
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 Breakers0381.
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
0 34. 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.
Manual Mirrors
If equipped, adjust manual mirrors
by moving the mirror up and down
or left to right to see a little of the
side of the vehicle and to have a
clear view behind the vehicle.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Seats and Restraints 57
Seats and
Restraints
Head Restraints
Head Restraints . . . . . . . . . . . . . . . 58
Front Seats
Seat Adjustment . . . . . . . . . . . . . . . 59
Center Seat . . . . . . . . . . . . . . . . . . . . 59
Power Seat Adjustment . . . . . . . . 60
Lumbar Adjustment . . . . . . . . . . . . 60
Reclining Seatbacks . . . . . . . . . . . 61
Memory Seats . . . . . . . . . . . . . . . . . 62
Heated and Ventilated FrontSeats . . . . . . . . . . . . . . . . . . . . . . . . . 65
Rear Seats
Rear Seats (Double Cab FullBench) . . . . . . . . . . . . . . . . . . . . . . . 66
Rear Seats (Split Bench) . . . . . . 68
Seat Belts
Seat Belts . . . . . . . . . . . . . . . . . . . . . 69
How to Wear Seat Belts Properly . . . . . . . . . . . . . . . . . . . . . . 70
Lap-Shoulder Belt . . . . . . . . . . . . . 71
Seat Belt Use During Pregnancy . . . . . . . . . . . . . . . . . . . . 74
Lap Belt . . . . . . . . . . . . . . . . . . . . . . . 75 Seat Belt Extender . . . . . . . . . . . . . 75
Safety System Check . . . . . . . . . . 75
Seat Belt Care . . . . . . . . . . . . . . . . . 76
Replacing Seat Belt System
Parts after a Crash . . . . . . . . . . . 76
Airbag System
Airbag System . . . . . . . . . . . . . . . . . 77
Where Are the Airbags? . . . . . . . 78
When Should an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . . 80
What Makes an Airbag Inflate? . . . . . . . . . . . . . . . . . . . . . . . 82
How Does an Airbag Restrain? . . . . . . . . . . . . . . . . . . . . . 82
What Will You See after an Airbag Inflates? . . . . . . . . . . . . . . 82
Airbag On-Off Switch . . . . . . . . . . 84
Passenger Sensing System . . . 86
Servicing the Airbag-Equipped Vehicle . . . . . . . . . . . . . . . . . . . . . . . 90
Adding Equipment to the Airbag-Equipped Vehicle . . . . . 90
Airbag System Check . . . . . . . . . . 91
Replacing Airbag System Parts after a Crash . . . . . . . . . . . . . . . . . 92
Child Restraints
Older Children . . . . . . . . . . . . . . . . . 92
Infants and Young Children . . . . 94
Child Restraint Systems . . . . . . . 96 Where to Put the Restraint . . . . . 98
Lower Anchors and Tethers for
Children (LATCH System) . . . . 99
Replacing LATCH System Parts After a Crash . . . . . . . . . . 111
Securing Child Restraints (With the Seat Belt in the
Rear Seat) . . . . . . . . . . . . . . . . . . 111
Securing Child Restraints (With the Seat Belt in the Center
Front Seat) . . . . . . . . . . . . . . . . . . 114
Securing Child Restraints (With the Seat Belt in the Front
Passenger Seat) . . . . . . . . . . . . 115

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Seats and Restraints 59
Rear Seats
The rear seat has adjustable
headrests in the outboard seating
positions.
The height of the headrest can be
adjusted. Pull the headrest up to
raise it. To lower the headrest, push
the headrest down.
If you are installing a child restraint
in the rear seat, see“Securing a
Child Restraint Designed for the
LATCH System” underLower
Anchors and Tethers for Children
(LATCH System) 099.
Front Seats
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.
To adjust a manual seat:
1. Pull the handle at the front of the seat. 2. Slide the seat to the desired
position and release the
handle.
3. Try to move the seat back and forth to be sure it is locked in
place.
To adjust the seatback, see
Reclining Seatbacks 061.
To adjust the lumbar support,
if equipped, see Lumbar Adjustment
0 60.
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.