2021 GMC TERRAIN service

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
242 Driving and Operating
for driver braking to occur more rapidly,
which can cause a brief, mild deceleration.
Continue to apply the brake pedal as
needed. Cruise control may be disengaged
when the Front Pedestrian Alert occurs.
Automatic Braking
If FPB detects it is about to crash into a
pedestrian directly ahead, and the brakes
have not been applied, FPB may
automatically brake moderately or brake
hard. This can help to avoid some very low
speed pedestrian crashes or reduce
pedestrian injury. FPB can automatically
brake to detected pedestrians between
8 km/h (5 mph) and 80 km/h (50 mph).
Automatic braking levels may be reduced
under certain conditions, such as higher
speeds.
If this happens, Automatic Braking may
engage the Electric Parking Brake (EPB) to
hold the vehicle at a stop. Release the EPB.
A firm press of the accelerator pedal will
also release Automatic Braking and the EPB.
{Warning
FPB may alert or automatically brake the
vehicle suddenly in situations where it is
unexpected and undesired. It could falsely
alert or brake for objects similar in shape
or size to pedestrians, including shadows.
This is normal operation and the vehicle
does not need service. To override
Automatic Braking, firmly press the
accelerator pedal, if it is safe to do so.
Automatic Braking can be disabled through
vehicle personalization. See “Front Pedestrian
Detection” in“Collision/Detection Systems”
under Vehicle Personalization 0108.
{Warning
Using the Front Pedestrian Braking
system while towing a trailer could cause
you to lose control of the vehicle and
crash. Turn the system to Alert or Off
when towing a trailer.
Cleaning the System
If FPB does not seem to operate properly,
cleaning the outside of the windshield in
front of the rearview mirror may correct the
issue.
Side Blind Zone Alert (SBZA)
If equipped, the SBZA system is a
lane-changing aid that assists drivers with
avoiding crashes that occur with moving
vehicles in the side blind zone, or blind spot
areas. When the vehicle is in a forward gear,
the left or right side mirror display will light
up if a moving vehicle is detected in that
blind zone. If the turn signal is activated and
a vehicle is also detected on the same side,
the display will flash as an extra warning
not to change lanes. Since this system is
part of the Lane Change Alert (LCA) system,
read the entire LCA section before using this
feature.
Lane Change Alert (LCA)
If equipped, the LCA system is a
lane-changing aid that assists drivers with
avoiding lane change crashes that occur with
moving vehicles in the side blind zone (or
spot) areas or with vehicles rapidly
approaching these areas from behind. The

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
244 Driving and Operating
side of the vehicle do not move further back
when a trailer is towed. Use caution while
changing lanes when towing a trailer. LCA
may alert to objects attached to the vehicle,
such as a trailer, bicycle, or object extending
out to either side of the vehicle. Attached
objects may also interfere with the
detection of vehicles. This is normal system
operation; the vehicle does not need service.
LCA may not always alert the driver to
vehicles in the next lane over, especially in
wet conditions or when driving on sharp
curves. The system does not need to be
serviced. The system may light up due to
guardrails, signs, trees, shrubs, and other
non-moving objects. This is normal system
operation; the vehicle does not need service.
LCA may not operate when the LCA sensors
in the left or right corners of the rear
bumper are covered with mud, dirt, snow,
ice, or slush, or in heavy rainstorms. For
cleaning instructions, see "Washing the
Vehicle" underExterior Care0322. If the
Driver Information Center (DIC) displays the
system unavailable message after cleaning
both sides of the vehicle toward the rear
corners of the vehicle, see your dealer. If the LCA displays do not light up when
moving vehicles are in the side blind zone or
are rapidly approaching this zone and the
system is clean, the system may need
service. Take the vehicle to your dealer.
Radio Frequency Information
See
Radio Frequency Statement 0354.
Lane Keep Assist (LKA)
If equipped, LKA may help avoid crashes due
to unintentional lane departures. This
system uses a camera to detect lane
markings between 60 km/h (37 mph) and
180 km/h (112 mph). It may assist by gently
turning the steering wheel if the vehicle
approaches a detected lane marking. It may
also provide a Lane Departure Warning
(LDW) alert if the vehicle crosses a detected
lane marking. LKA can be overriden by
turning the steering wheel. This system is
not intended to keep the vehicle centered in
the lane. LKA will not assist and alert if the
turn signal is active in the direction of lane
departure, or if it detects that you are
accelerating, braking or actively steering.
{Warning
The LKA system does not continuously
steer the vehicle. It may not keep the
vehicle in the lane or give a Lane
Departure Warning (LDW) alert, even if a
lane marking is detected.
The LKA and LDW systems may not:
.Provide an alert or enough steering
assist to avoid a lane departure or
crash.
.Detect lane markings under poor
weather or visibility conditions. This
can occur if the windshield or
headlamps are blocked by dirt, snow,
or ice; if they are not in proper
condition; or if the sun shines directly
into the camera.
.Detect road edges.
.Detect lanes on winding or hilly roads.
If LKA only detects lane markings on one
side of the road, it will only assist or
provide an LDW alert when approaching
the lane on the side where it has
detected a lane marking. Even with LKA
and LDW, you must steer the vehicle. (Continued)

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
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Driving and Operating 245
Warning (Continued)
Always keep your attention on the road
and maintain proper vehicle position
within the lane, or vehicle damage,
injury, or death could occur. Always keep
the windshield, headlamps, and camera
sensors clean and in good repair. Do not
use LKA in bad weather conditions or on
roads with unclear lane markings, such as
construction zones.
{Warning
Using LKA while towing a trailer or on
slippery roads could cause loss of control
of the vehicle and a crash. Turn the
system off.
How the System Works
LKA uses a camera sensor installed on the
windshield ahead of the rearview mirror to
detect lane markings. It may provide brief
steering assist if it detects an unintended
lane departure. It may further provide an
audible alert or the driver seat may pulse
indicating that a lane marking has been
crossed.To turn LKA on and off, press
Aon the
center console. If equipped, the indicator
light on the button comes on when LKA is
on and turns off when LKA is disabled.
When on,
Ais white, if equipped,
indicating that the system is not ready to
assist.
Ais green if LKA is ready to
assist. LKA may assist by gently turning the
steering wheel if the vehicle approaches a
detected lane marking.
Ais amber when
assisting. It may also provide a Lane
Departure Warning (LDW) alert by flashing
Aamber if the vehicle crosses a
detected lane marking. Additionally, there
may be three beeps, or the driver seat may
pulse three times, on the right or left,
depending on the lane departure direction.
Take Steering
The LKA system does not continuously steer
the vehicle. If LKA does not detect active
driver steering, an alert and chime may be
provided. Steer the vehicle to dismiss. LKA
may become temporarily unavailable after
repeated take steering alerts.
When the System Does Not Seem to
Work Properly
The system performance may be
affected by:
.Close vehicles ahead.
.Sudden lighting changes, such as when
driving through tunnels.
.Banked roads.
.Roads with poor lane markings, such as
two-lane roads.
If the LKA system is not functioning
properly when lane markings are clearly
visible, cleaning the windshield may help.
A camera blocked message may display if
the camera is blocked. Some driver
assistance systems may have reduced
performance or not work at all. An LKA or
LDW unavailable message may display if the
systems are temporarily unavailable. This
message could be due to a blocked camera.
The LKA system does not need service. Clean
the outside of the windshield behind the
rearview mirror.
LKA assistance and/or LDW alerts may occur
due to tar marks, shadows, cracks in the
road, temporary or construction lane
markings, or other road imperfections. This

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
246 Driving and Operating
is normal system operation; the vehicle does
not need service. Turn LKA off if these
conditions continue.
Fuel
Top Tier Fuel
GM recommends the use of TOP TIER
Detergent Gasoline to keep the engine clean,
reduce engine deposits, and maintain
optimal vehicle performance. Look for the
TOP TIER Logo or see www.toptiergas.com
for a list of TOP TIER Detergent Gasoline
marketers and applicable countries.
Recommended Fuel (LYX - 1.5L L4
Turbo Engine)
Use regular unleaded gasoline meeting
ASTM specification D4814 with a posted
octane rating of 87—(R+M)/2 —or higher.
Do not use gasoline with a posted octane
rating of less than 87, as this may cause
engine knock and will lower fuel economy.
Do not use any fuel labeled E85 or FlexFuel.
Do not use gasoline with ethanol levels
greater than 15% by volume.
Prohibited Fuels
Caution
Do not use fuels with any of the
following conditions; doing so may
damage the vehicle and void its
warranty:
(Continued)
Caution (Continued)
.For vehicles that are not FlexFuel, fuel
labeled greater than 15% ethanol by
volume, such as mid-level ethanol
blends (16–50% ethanol), E85,
or FlexFuel.
.Fuel with any amount of methanol,
methylal, ferrocene, and aniline. These
fuels can corrode metal fuel system
parts or damage plastic and rubber
parts.
.Fuel containing metals such as
methylcyclopentadienyl manganese
tricarbonyl (MMT), which can damage
the emissions control system and
spark plugs.
.Fuel with a posted octane rating of
less than the recommended fuel. Using
this fuel will lower fuel economy and
performance, and may decrease the
life of the emissions catalyst.
Fuels in Foreign Countries
The U.S., Canada, and Mexico post fuel
octane ratings in anti-knock index (AKI). For
fuel not to use in a foreign country, see
Prohibited Fuels 0246.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
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Driving and Operating 251
Make wider turns than normal when towing,
so trailer will not go over soft shoulders,
over curbs, or strike road signs, trees,
or other objects. Always signal turns well in
advance. Do not steer or brake suddenly.
Driving on Grades
Reduce speed and shift to a lower gear
before starting down a long or steep
downhill grade. If the transmission is not
shifted down, the brakes may overheat and
result in reduced braking efficiency.
The vehicle can tow in D (Drive). Shift the
transmission to a lower gear if the
transmission shifts too often under heavy
loads and/or hilly conditions.
When towing at higher altitudes, engine
coolant will boil at a lower temperature
than at lower altitudes. If the engine is
turned off immediately after towing at high
altitude on steep uphill grades, the vehicle
could show signs similar to engine
overheating. To avoid this, let the engine
run, preferably on level ground, with the
transmission in P (Park) for a few minutes
before turning the engine off. If the
overheat warning comes on, seeEngine
Overheating 0270.
Parking on Hills
{Warning
To prevent serious injury or death,
always park your vehicle and trailer on a
level surface when possible.
When parking your vehicle and your trailer
on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn the wheels into
the curb if facing downhill or into traffic
if facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, gradually release the brake pedal to
allow the chocks to absorb the load of
the trailer.
4. Reapply the brake pedal. Then apply the parking brake and shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
.Start the engine.
.Shift into a gear.
.Release the parking brake. 2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of
the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
The vehicle needs service more often when
used to tow trailers. See Maintenance
Schedule 0331. It is especially important to
check the automatic transmission fluid,
engine oil, axle lubricant, belts, cooling
system, and brake system before and during
each trip.
Check periodically that all nuts and bolts on
the trailer hitch are tight.
Engine Cooling When Trailer Towing
The cooling system may temporarily
overheat during severe operating conditions.
See Engine Overheating 0270.
Trailer Towing
Caution
Towing a trailer improperly can damage
the vehicle and result in costly repairs
not covered by the vehicle warranty. To
(Continued)

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
256 Driving and Operating
Conversions and Add-Ons
Add-On Electrical Equipment
{Warning
The Data Link Connector (DLC) is used for
vehicle service and Emission Inspection/
Maintenance testing. SeeMalfunction
Indicator Lamp (Check Engine Light) 093.
A device connected to the DLC —such as
an aftermarket fleet or driver-behavior
tracking device —may interfere with
vehicle systems. This could affect vehicle
operation and cause a crash. Such devices
may also access information stored in the
vehicle’s systems.
Caution
Some electrical equipment can damage
the vehicle or cause components to not
work and would not be covered by the
vehicle warranty. Always check with your
dealer before adding electrical equipment.
Add-on equipment can drain the vehicle's
12-volt battery, even if the vehicle is not
operating. The vehicle has an airbag system. Before
attempting to add anything electrical to the
vehicle, see
Servicing the Airbag-Equipped
Vehicle 055 and
Adding Equipment to the Airbag-Equipped
Vehicle 056.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
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Vehicle Care 257
Vehicle Care
General Information
General Information . . . . . . . . . . . . . . . . . . . 258
California Proposition 65 Warning . . . . . 258
California Perchlorate MaterialsRequirements . . . . . . . . . . . . . . . . . . . . . . . . 258
Accessories and Modifications . . . . . . . . . 258
Vehicle Checks
Doing Your Own Service Work . . . . . . . . 259
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
Engine Compartment Overview . . . . . . . . 261
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
Engine Oil Life System . . . . . . . . . . . . . . . . 264
Automatic Transmission Fluid . . . . . . . . . 265
Engine Air Filter Life System . . . . . . . . . . 265
Engine Air Cleaner/Filter . . . . . . . . . . . . . . 265
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 267
Engine Overheating . . . . . . . . . . . . . . . . . . . 270
Washer Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
Brake Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Battery - North America . . . . . . . . . . . . . . . 273
All-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . 274
Starter Switch Check . . . . . . . . . . . . . . . . . . 274
Park Brake and P (Park) Mechanism Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274
Wiper Blade Replacement . . . . . . . . . . . . . 275
Windshield Replacement . . . . . . . . . . . . . . 276 Gas Strut(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
Headlamp Aiming
Front Headlamp Aiming . . . . . . . . . . . . . . . 277
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . 277
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . 277
High Intensity Discharge (HID)
Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
LED Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Front Turn Signal Lamps . . . . . . . . . . . . . . . 278
Taillamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
License Plate Lamp . . . . . . . . . . . . . . . . . . . . 279
Electrical System
Electrical System Overload . . . . . . . . . . . . 280
Fuses and Circuit Breakers . . . . . . . . . . . . 280
Engine Compartment Fuse Block . . . . . . . 281
Instrument Panel Fuse Block . . . . . . . . . . 284
Rear Compartment Fuse Block . . . . . . . . . 285
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
All-Season Tires . . . . . . . . . . . . . . . . . . . . . . . . 287
Winter Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
Summer Tires . . . . . . . . . . . . . . . . . . . . . . . . . 288
Tire Sidewall Labeling . . . . . . . . . . . . . . . . . 288
Tire Designations . . . . . . . . . . . . . . . . . . . . . 290
Tire Terminology and Definitions . . . . . . 291
Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Tire Pressure Monitor System . . . . . . . . . 294 Tire Pressure Monitor Operation . . . . . . 295
Tire Inspection . . . . . . . . . . . . . . . . . . . . . . . . 298
Tire Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . 298
When It Is Time for New Tires . . . . . . . . 299
Buying New Tires . . . . . . . . . . . . . . . . . . . . . 300
Different Size Tires and Wheels . . . . . . . 301
Uniform Tire Quality Grading . . . . . . . . . . 301
Wheel Alignment and Tire Balance . . . . 302
Wheel Replacement . . . . . . . . . . . . . . . . . . . 302
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
If a Tire Goes Flat . . . . . . . . . . . . . . . . . . . . . 303
Tire Sealant and Compressor Kit . . . . . . 305
Storing the Tire Sealant and
Compressor Kit . . . . . . . . . . . . . . . . . . . . . . 310
Tire Changing . . . . . . . . . . . . . . . . . . . . . . . . . 310
Compact Spare Tire . . . . . . . . . . . . . . . . . . . . 315
Jump Starting
Jump Starting - North America . . . . . . . . 316
Towing the Vehicle
Towing the Vehicle . . . . . . . . . . . . . . . . . . . . 318
Recreational Vehicle Towing . . . . . . . . . . . 320
Appearance Care
Exterior Care . . . . . . . . . . . . . . . . . . . . . . . . . . 322
Interior Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
Floor Mats . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
258 Vehicle Care
General Information
For service and parts needs, visit your
dealer. You will receive genuine GM parts
and GM-trained and supported service
people.
Genuine GM parts have one of these marks:
California Proposition 65 Warning
{Warning
Most motor vehicles, including this one,
as well as many of its service parts and
fluids, contain and/or emit chemicals
known to the State of California to cause(Continued)
Warning (Continued)
cancer and birth defects or other
reproductive harm. Engine exhaust, many
parts and systems, many fluids, and
some component wear by-products
contain and/or emit these chemicals. For
more information go to
www.P65Warnings.ca.gov/
passenger-vehicle.
See Battery - North America 0273 and
Jump Starting - North America 0316 and the
back cover.
California Perchlorate Materials
Requirements
Certain types of automotive applications,
such as airbag initiators, seat belt
pretensioners, and lithium batteries
contained in electronic keys, may contain
perchlorate materials. Perchlorate Material –
special handling may apply. See
www.dtsc.ca.gov/hazardouswaste/
perchlorate.
Accessories and Modifications
Adding non-dealer accessories or making
modifications to the vehicle can affect
vehicle performance and safety, including
such things as airbags, braking, stability,
ride and handling, emissions systems,
aerodynamics, durability, and electronic
systems like antilock brakes, traction control,
and stability control. These accessories or
modifications could even cause malfunction
or damage not covered by the vehicle
warranty.
Damage to suspension components caused
by modifying vehicle height outside of
factory settings will not be covered by the
vehicle warranty.
Damage to vehicle components resulting
from modifications or the installation or use
of non-GM certified parts, including control
module or software modifications, is not
covered under the terms of the vehicle
warranty and may affect remaining
warranty coverage for affected parts.
GM Accessories are designed to complement
and function with other systems on the
vehicle. See your dealer to accessorize the
vehicle using genuine GM Accessories
installed by a dealer technician.