2021 GMC TERRAIN service

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Keys, Doors, and Windows . . . . . . . . . . . . . . . 6
Seats and Restraints . . . . . . . . . . . . . . . . . . . . . 29
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Instruments and Controls . . . . . . . . . . . . . . . . 78
Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Infotainment System . . . . . . . . . . . . . . . . . . . 123
Climate Controls . . . . . . . . . . . . . . . . . . . . . . . . 178
Driving and Operating . . . . . . . . . . . . . . . . . . 185
Vehicle Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
Service and Maintenance . . . . . . . . . . . . . . . 330
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . 342
Customer Information . . . . . . . . . . . . . . . . . . 346
Reporting Safety Defects . . . . . . . . . . . . . . . 354
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357
Connected Services . . . . . . . . . . . . . . . . . . . . . 362
Index . . . . . . . . . . . . . . . . . . . . . . . . . . 365
Introduction
The names, logos, emblems, slogans, vehicle
model names, and vehicle body designs
appearing in this manual including, but not
limited to, GM, the GM logo, GMC, the GMC
Truck Emblem, TERRAIN, and DENALI are
trademarks and/or service marks of General
Motors LLC, its subsidiaries, affiliates,
or licensors.
For vehicles first sold in Canada, substitute
the name“General Motors of Canada
Company” for GMC Motor Division wherever
it appears in this manual.
This manual describes features that may or
may not be on the vehicle because of
optional equipment that was not purchased
on the vehicle, model variants, country
specifications, features/applications that may not be available in your region, or changes
subsequent to the printing of this owner’s
manual.
Refer to the purchase documentation
relating to your specific vehicle to confirm
the features.
Keep this manual in the vehicle for quick
reference.Canadian Vehicle Owners
A French language manual can be obtained
from your dealer, at www.helminc.com,
or from:
Propriétaires Canadiens
On peut obtenir un exemplaire de ce guide
en français auprès du concessionnaire ou à
l'adresse suivante:
Helm, Incorporated
Attention: Customer Service
47911 Halyard Drive
Plymouth, MI 48170
USA
Litho in U.S.A.
Part No. 84443536 B Second Printing©2020 General Motors LLC. All Rights Reserved.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
2 Introduction
Using this Manual
To quickly locate information about the
vehicle, use the Index in the back of the
manual. It is an alphabetical list of what is
in the manual and the page number where
it can be found.
About Driving the Vehicle
As with other vehicles of this type, failure to
operate this vehicle correctly may result in
loss of control or a crash. Be sure to read
the driving guidelines in this manual in the
section called“Driving and Operating” and
specifically Driver Behavior 0186, Driving
Environment 0186, and Vehicle Design
0 186.
Danger, Warning, and Caution
Warning messages found on vehicle labels
and in this manual describe hazards and
what to do to avoid or reduce them.
{Danger
Danger indicates a hazard with a high
level of risk which will result in serious
injury or death.
{Warning
Warning indicates a hazard that could
result in injury or death.
Caution
Caution indicates a hazard that could
result in property or vehicle damage.
A circle with a slash through it is a safety
symbol which means “Do not,” “Do not do
this,” or“Do not let this happen.”
Symbols
The vehicle has components and labels that
use symbols instead of text. Symbols are
shown along with the text describing the
operation or information relating to a
specific component, control, message, gauge,
or indicator.
M:Shown when the owner’s manual has
additional instructions or information.
*: Shown when the service manual has
additional instructions or information.
0: Shown when there is more information
on another page — “see page.”
Vehicle Symbol Chart
Here are some additional symbols that may
be found on the vehicle and what they
mean. See the features in this manual for
information.
u: Air Conditioning System
G:Air Conditioning Refrigerant Oil
9:Airbag Readiness Light
!:Antilock Brake System (ABS)
$:Brake System Warning Light
9:Dispose of Used Components Properly
P:Do Not Apply High Pressure Water
B:Engine Coolant Temperature
_:Flame/Fire Prohibited
H: Flammable

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Keys, Doors, and Windows 7
The key, inside the Remote Keyless Entry
(RKE) transmitter, is used for the driver door.
To remove the key, press the button near
the bottom of the transmitter, and pull the
key out. Never pull the key out without
pressing the button.
If it becomes difficult to turn the key,
inspect the key blade for debris.
See your dealer if a new key is needed.
Contact Roadside Assistance if locked out of
the vehicle. SeeRoadside Assistance Program
0 349.
With an active OnStar or connected service
plan, an OnStar Advisor may remotely
unlock the vehicle. See OnStar Overview
0 357.
Remote Keyless Entry (RKE)
System
See Radio Frequency Statement 0354.
If there is a decrease in the Remote Keyless
Entry (RKE) operating range:
.Check the distance. The transmitter may
be too far from the vehicle.
.Check the location. Other vehicles or
objects may be blocking the signal.
.Check the transmitter's battery. See
“Battery Replacement” later in this
section.
.If the transmitter is still not working
correctly, see your dealer or a qualified
technician for service.
Remote Keyless Entry (RKE)
System Operation
The Keyless Access system allows for vehicle
entry when the Remote Keyless Entry (RKE)
transmitter is within 1 m (3 ft). See “Keyless
Access Operation” following.
The RKE transmitter functions may work up
to 60 m (197 ft) away from the vehicle.
Other conditions can impact the
performance of the transmitter. See Remote
Keyless Entry (RKE) System 07.
With Remote Start Shown, Without Similar

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
20 Keys, Doors, and Windows
liftgate continues to automatically close
after opening, see your dealer for service
before using the power liftgate.
Interfering with the power liftgate motion
or manually closing the liftgate too quickly
after power opening may resemble a
support strut failure. This could also activate
the falling liftgate detection feature. Allow
the liftgate to complete its operation and
wait a few seconds before manually closing
the liftgate.
Obstacle Detection Features
If the liftgate encounters an obstacle during
a power open or close cycle, the liftgate will
automatically reverse direction and move a
short distance away from the obstacle. After
removing the obstruction, the power liftgate
operation can be used again. If the liftgate
encounters multiple obstacles on the same
power cycle, the power function will
deactivate. After removing the obstructions,
manually close the liftgate which will allow
normal power operation functions to
resume.If the vehicle is locked while the liftgate is
closing, and an obstacle is encountered that
prevents the liftgate from completely
closing, the horn will sound as an alert that
the liftgate did not close.
Setting the 3/4 Mode
To change the position the liftgate stops at
when opening:
1. Select MAX or 3/4 mode and power open the liftgate.
2. Stop the liftgate movement at the desired height by pressing any liftgate
switch. Manually adjust the liftgate
position if needed.
3. Press and hold
lnext to the pull cup
on the bottom of the liftgate until the
turn signals flash and a beep sounds.
This indicates the setting has been
recorded.
The liftgate cannot be set below a minimum
programmable height. If there is no light
flash or sound, then the height adjustment
may be too low.
Manual Operation
Select OFF to manually operate the liftgate.
Caution
Attempting to move the liftgate too
quickly and with excessive force may
result in damage to the vehicle.
Operate the liftgate manually with a
smooth motion and moderate speed. The
system includes a feature which limits the
manual closing speed to protect the
components.
To open the liftgate, pressKon the power
door lock switch or press
Kon the RKE
transmitter twice to unlock all doors. Press
the touch pad on the underside of the
liftgate handle and lift up.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Keys, Doors, and Windows 23
.PressKon the RKE transmitter.
.Start the vehicle.
To avoid setting off the alarm by accident:
.Lock the vehicle after all occupants have
left the vehicle and all doors are closed.
.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 and the lights flash three
times, an alarm occurred previously while
the alarm system was armed.
If the alarm has been activated, a message
will appear on the Driver Information
Center (DIC).
Immobilizer
See Radio Frequency Statement 0354.
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 transmitter leaves the vehicle.
The immobilization system is disarmed
when the ignition is turned on or in ACC/
ACCESSORY and a valid Remote Keyless
Entry (RKE) transmitter is in the vehicle.
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 ignition will not change from off to
on or ACC/ACCESSORY, and the RKE
transmitter appears to be undamaged, try
another transmitter. Or, you may try placing
the transmitter in the cupholder in the
center console. See
Remote Keyless Entry
(RKE) System Operation 07.
If the ignition mode will not change with
the other transmitter, or with the
transmitter in the cupholder, 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 to the vehicle. To program
additional transmitters, see “Programming
Transmitters to the Vehicle” underRemote
Keyless Entry (RKE) System Operation 07.
Do not leave the key or device that disarms
or deactivates the theft-deterrent system in
the vehicle.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
52 Seats and Restraints
{Warning
A crash severe enough to inflate the
airbags may have also damaged
important functions in the vehicle, such
as the fuel system, brake and steering
systems, etc. Even if the vehicle appears
to be drivable after a moderate crash,
there may be concealed damage that
could make it difficult to safely operate
the vehicle.
Use caution if you should attempt to
restart the engine after a crash has
occurred.
In many crashes severe enough to inflate
the airbag, windshields are broken by
vehicle deformation. Additional windshield
breakage may also occur from the front
outboard passenger airbag.
.Airbags are designed to inflate only once.
After an airbag inflates, you will need
some new parts for the airbag system.
If you do not get them, the airbag
system will not be there to help protect
you in another crash. A new system will
include airbag modules and possibly other
parts. The service manual for the vehicle
covers the need to replace other parts.
.The vehicle has a crash sensing and
diagnostic module which records
information after a crash. See Vehicle
Data Recording and Privacy 0355 and
Event Data Recorders 0356.
.Let only qualified technicians work on the
airbag systems. Improper service can
mean that an airbag system will not work
properly. See your dealer for service.
Passenger Sensing System
The vehicle has a passenger sensing system
for the front outboard passenger position.
The passenger airbag status indicator will
light on the overhead console when the
vehicle is started.
The words ON and OFF, and 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, and the symbol
for on or off, will be visible. See Passenger
Airbag Status Indicator 092. 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 airbag inflates. This is
(Continued)

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Seats and Restraints 53
Warning (Continued)
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 secure child
restraints in the rear seat. Consider using
another vehicle to transport the child
when a rear seat is not available.
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
0 92.
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 092
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.
2. Remove the child restraint from the vehicle.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Seats and Restraints 55
6. Restart the vehicle and have the personremain in this position for two to
three minutes after the ON indicator
is lit.
{Warning
If the front outboard passenger airbag is
turned off for an adult-sized occupant,
the airbag will not be able to inflate and
help protect that person in a crash,
resulting in an increased risk of serious
injury or even death. An adult-sized
occupant should not ride in the front
outboard passenger seat, if the passenger
airbag OFF indicator is lit.
Additional Factors Affecting System
Operation
Seat belts help keep the passenger in
position on the seat during vehicle
maneuvers and braking, which helps the
passenger sensing system maintain the
passenger airbag status. See “Seat Belts”
and “Child Restraints” in the Index for
additional information about the importance
of proper restraint use. A thick layer of additional material, such as
a blanket or cushion, or aftermarket
equipment such as seat covers, seat heaters,
and seat massagers can affect how well the
passenger sensing system operates. We
recommend that you not use seat covers or
other aftermarket equipment except when
approved by GM for your specific vehicle.
See
Adding Equipment to the
Airbag-Equipped Vehicle 056 for more
information about modifications that can
affect how the system operates.
The ON indicator may be lit if an object,
such as a briefcase, handbag, grocery bag,
laptop, or other electronic device, is put on
an unoccupied seat. If this is not desired,
remove the object from the seat.{Warning
Stowing articles under the passenger seat
or between the passenger seat cushion
and seatback may interfere with the
proper operation of the passenger
sensing system.
Servicing the Airbag-Equipped
Vehicle
Airbags affect how the vehicle should be
serviced. There are parts of the airbag
system in several places around the vehicle.
Your dealer and the service manual have
information about servicing the vehicle and
the airbag system. To purchase a service
manual, see Publication Ordering
Information 0353.
{Warning
For up to 10 seconds after the vehicle is
turned off and the battery is
disconnected, an airbag can still inflate
during improper service. You can be
injured if you are close to an airbag
when it inflates. Avoid yellow connectors.
They are probably part of the airbag
system. Be sure to follow proper service
procedures, and make sure the person
performing work for you is qualified to
do so.