check engine light GMC TERRAIN 2021 User Guide

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Instruments and Controls 105
engine speed, outside temperature, and oil
viscosity. On some models, the oil pump will
vary engine oil pressure according to engine
needs. Oil pressure may change quickly as
the engine speed or load varies. This is
normal. If the oil pressure warning light or
Driver Information Center (DIC) message
indicates oil pressure outside the normal
operating range, check the vehicle's oil as
soon as possible.
Driver Information Center (DIC)
(Uplevel)
The DIC displays are shown in the center of
the instrument cluster in the Info App.
SeeInstrument Cluster (Base and Midlevel)
0 85 or
Instrument Cluster (Uplevel) 088. The
displays show the status of many vehicle
systems.worx: Press to move up or down in
a list.
oorp: Press to move between the
interactive display zones in the cluster.
V: Press to open a menu or select a menu
item. Press and hold to reset values on
certain screens.
Info Page Options
The info pages on the DIC can be turned on
or off through the Options menu.
1. Press
oorpto scroll to the Options
application.
2. Press
worxto scroll to the Info Page
Options and press
V. 3. Press
worxto move through the list
of possible information displays.
4. Press
Vwhile an item is highlighted to
select or deselect that item. When an
item is selected, a checkmark will appear
next to it.
Info Pages
The following is the list of all possible DIC
info page displays. Some may not be
available for your particular vehicle. Some
items may not be turned on by default but
can be turned on through the Options app.
See “Info Page Options” earlier in this
section.
Speed : Shows the vehicle speed in either
kilometers per hour (km/h) or miles per
hour (mph). If equipped, press
Vto open
the menu and select to display speed limit
signs. The sign will show “− −”when there
is no detected speed limit or the system is
unavailable.
Speed Limit : Shows sign information, which
comes from a roadway database in the
onboard navigation, if equipped. The sign
will show “− −”when there is no detected
speed limit or the system is unavailable.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Instruments and Controls 107
selected distance. Displayed below the bar
graph is the best average fuel economy that
has been achieved for the selected distance.
The selected distance is displayed at the top
of the page as“last xxx mi/km.”
Press
Vto select the distance or reset best
value. Use
wandxto choose the
distance and press
V. Presswandxto
select “Reset Best Score.” Press
Vto reset
the best average fuel economy. After reset,
the best value displays “-,-”until the
selected distance has been traveled.
The display provides information on how
current driving behavior affects the running
average and how well recent driving
compares to the best that has been
achieved for the selected distance.
Average Speed : Displays the average
vehicle speed of the vehicle in kilometers
per hour (km/h) or miles per hour (mph).
This average is based on the various vehicle
speeds recorded since the last reset. Reset
the average speed by pressing
Vwhile this
display is active to show a confirmation
window to select yes or no and press
V. Timer :
This display can be used as a timer.
To start the timer, press
Vto open the
menu while this display is active. Use
w
andxto select Start Timer or Reset. Press
V. To stop the timer, pressVwhile this
display is active. The display will show the
amount of time that has passed since the
timer was last reset.
Follow Distance/Gap Setting : If equipped,
the current follow time to the vehicle ahead
is displayed as a time value on this page.
When Adaptive Cruise Control (ACC) has
been engaged, the display switches to the
gap setting page. This page shows the
current gap setting along with the vehicle
ahead indicator.
Driver Assistance : If equipped, shows
information for Lane Keep Assist (LKA), Lane
Departure Warning (LDW), and Forward
Collision Alert (FCA).
Battery Voltage : Displays the current
battery voltage, if equipped. Battery voltage
changes are normal while driving. See
Charging System Light 093. If there is a
problem with the battery charging system, a
DIC will display a message. Coolant Temperature :
Displays the coolant
temperature in degrees Celsius (°C) or
degrees Fahrenheit (°F).
Economy Trend : Shows history of the
Average Fuel Economy from the last 50 km
(30 mi). Each bar represents about 5 km
(3 mi) of driving. During driving the bars will
shift to always reflect the most recent
distance on the right side. Press
Vto open
the menu while this display is active to clear
the graph. Select yes or no and press
V.
Oil Pressure : Oil pressure is displayed in
either kilopascal (kPa) or in pounds per
square inch (psi). Oil pressure can vary with
engine speed, outside temperature, and oil
viscosity. On some models, the oil pump will
vary engine oil pressure according to engine
needs. Oil pressure may change quickly as
the engine speed or load varies. This is
normal. If the oil pressure warning light or
DIC message indicates oil pressure outside
the normal operating range, check the
vehicle's oil as soon as possible.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Driving and Operating 193
{Warning
Driving on frozen lakes, ponds, or rivers
can be dangerous. Ice conditions vary
greatly and the vehicle could fall through
the ice; you and your passengers could
drown. Drive your vehicle on safe
surfaces only.
Driving in Water
{Warning
Driving through rushing water can be
dangerous. Deep water can sweep your
vehicle downstream and you and your
passengers could drown. If it is only
shallow water, it can still wash away the
ground from under your tires. Traction
could be lost, and the vehicle could roll
over. Do not drive through rushing water.
Caution
Do not drive through standing water if it
is deep enough to cover the wheel hubs,
axles, or exhaust pipe. Deep water can
damage the axle and other vehicle parts.If the standing water is not too deep, drive
through it slowly. At faster speeds, water
can get into the engine and cause it to stall.
Stalling can occur if the exhaust pipe is
under water. Do not turn off the ignition
when driving through water. If the exhaust
pipe is under water, the engine will not
start. When going through water, the brakes
get wet and it may take longer to stop. See
Driving on Wet Roads
0193.
After Off-Road Driving
Remove any brush or debris that has
collected on the underbody or chassis,
or under the hood. These accumulations can
be a fire hazard.
After operation in mud or sand, have the
brake linings cleaned and checked. These
substances can cause glazing and uneven
braking. Check the body structure, steering,
suspension, wheels, tires, and exhaust
system for damage and check the fuel lines
and cooling system for any leakage.
More frequent maintenance service is
required. See the Maintenance Schedule
0 331.
Driving on Wet Roads
Rain and wet roads can reduce vehicle
traction and affect your ability to stop and
accelerate. Always drive slower in these
types of driving conditions and avoid driving
through large puddles and deep-standing or
flowing water.
{Warning
Wet brakes can cause crashes. They
might not work as well in a quick stop
and could cause pulling to one side. You
could lose control of the vehicle.
After driving through a large puddle of
water or a car/vehicle wash, lightly apply
the brake pedal until the brakes work
normally.
Flowing or rushing water creates strong
forces. Driving through flowing water
could cause the vehicle to be carried
away. If this happens, you and other
vehicle occupants could drown. Do not
ignore police warnings and be very
cautious about trying to drive through
flowing water.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
212 Driving and Operating
Automatic Engine Grade Braking
Automatic Engine Grade Braking assists
when driving downhill. It maintains vehicle
speed by automatically implementing a shift
pattern that uses the engine and the
transmission to slow the vehicle. The system
will automatically command downshifts to
reduce vehicle speed. The normal shift
pattern will return once the vehicle is on a
low grade or when the accelerator pedal is
pressed.
While in the Electronic Range Select (ERS)
mode, grade braking is deactivated, allowing
the driver to select a range and limiting the
highest gear available. Grade braking is
available for normal driving and in Tow/
Haul Mode.
SeeAutomatic Transmission 0208.
Drive Systems
All-Wheel Drive
For information on All-Wheel Drive (AWD),
see Driver Mode Control 0218.
Brakes
Antilock Brake System (ABS)
The Antilock Brake System (ABS) helps
prevent a braking skid and maintain steering
while braking hard.
ABS performs a system check when the
vehicle is first driven. A momentary motor
or clicking noise may be heard while this
test is going on, and the brake pedal may
move slightly. This is normal.
If there is a problem with ABS, this warning
light stays on. See Antilock Brake System
(ABS) Warning Light 096.
ABS does not change the time needed to
get a foot on the brake pedal and does not
always decrease stopping distance. If you
get too close to the vehicle ahead, there will
not be enough time to apply the brakes if
that vehicle suddenly slows or stops. Always
leave enough room ahead to stop, even
with ABS.
Using ABS
Do not pump the brakes. Just hold the brake
pedal down firmly. Hearing or feeling ABS
operate is normal.
Braking in Emergencies
ABS allows steering and braking at the same
time. In many emergencies, steering can
help even more than braking.
Electric Parking Brake
The Electric Parking Brake (EPB) can always
be applied, even if the vehicle is off. In case
of insufficient electrical power, the EPB

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/
Mexico-14420055) - 2021 - CRC - 11/13/20
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
272 Vehicle Care
pads are needed. The sound can come and
go or can be heard all the time when the
vehicle is moving, except when applying the
brake pedal firmly.
{Warning
The brake wear warning sound means
that soon the brakes will not work well.
That could lead to a crash. When the
brake wear warning sound is heard, have
the vehicle serviced.
Caution
Continuing to drive with worn-out brake
pads could result in costly brake repair.
Some driving conditions or climates can
cause a brake squeal when the brakes are
first applied or lightly applied. This does not
mean something is wrong with the brakes.
Properly torqued wheel nuts are necessary
to help prevent brake pulsation. When tires
are rotated, inspect brake pads for wear and
evenly tighten wheel nuts in the proper
sequence to torque specifications. See
Capacities and Specifications 0343.
Brake pads should be replaced as
complete sets.
Brake Pedal Travel
See your dealer if the brake pedal does not
return to normal height, or if there is a
rapid increase in pedal travel. This could be
a sign that brake service may be required.
Replacing Brake System Parts
Always replace brake system parts with
new, approved replacement parts. If this is
not done, the brakes may not work
properly. The braking performance expected
can change in many other ways if the
wrong replacement brake parts are installed
or if parts are improperly installed.
Brake Fluid
The brake master cylinder reservoir is filled
with GM approved DOT 3 brake fluid as
indicated on the reservoir cap. See Engine
Compartment Overview 0261 for the
location of the reservoir. Checking Brake Fluid
With the vehicle in P (Park) on a level
surface, the brake fluid level should be
between the minimum and maximum marks
on the brake fluid reservoir.
There are only two reasons why the brake
fluid level in the reservoir may go down:
.Normal brake lining wear. When new
linings are installed, the fluid level goes
back up.
.A fluid leak in the brake hydraulic system.
Have the brake hydraulic system fixed.
With a leak, the brakes will not
work well.
Always clean the brake fluid reservoir cap
and the area around the cap before
removing it.
Do not top off the brake fluid. Adding fluid
does not correct a leak. If fluid is added
when the linings are worn, there will be too
much fluid when new brake linings are
installed. Add or remove fluid, as necessary,
only when work is done on the brake
hydraulic system.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Vehicle Care 317
1. Discharged Battery NegativeGrounding Stud
2. Discharged Battery Positive Terminal
3. Good Battery Negative Terminal
4. Good Battery Positive Terminal
The jump start negative grounding stud (1)
for the discharged battery is to the left of
the windshield washer fluid reservoir.
The jump start positive terminal on the
discharged battery (2) is located in the
engine compartment on the driver side of
the vehicle.
The jump start positive terminal (4) and
negative terminal (3) are on the battery of
the vehicle providing the jump start. The positive jump start connection for the
discharged battery is under a trim cover.
Open the cover to expose the terminal.
1. Check the other vehicle. It must have a 12-volt battery with a negative ground
system.
Caution
If the other vehicle does not have a
12-volt system with a negative ground,
both vehicles can be damaged. Only use
a vehicle that has a 12-volt system with a
negative ground for jump starting.
2. Position the two vehicles so that they are not touching.
3. Set the parking brake. See Shifting Into
Park 0204.
Caution
If any accessories are left on or plugged
in during the jump starting procedure,
they could be damaged. The repairs
would not be covered by the vehicle
warranty. Whenever possible, turn off or
unplug all accessories on either vehicle
when jump starting. 4. Turn the ignition off. Turn off all lights
and accessories in both vehicles, except
the hazard warning flashers if needed.
{Warning
An electric fan can start up even when
the engine is not running and can injure
you. Keep hands, clothing, and tools
away from any underhood electric fan.
{Warning
Using a match near a battery can cause
battery gas to explode. People have been
hurt doing this, and some have been
blinded. Use a flashlight if you need
more light.
Battery fluid contains acid that can burn
you. Do not get it on you. If you
accidentally get it in your eyes or on
your skin, flush the place with water and
get medical help immediately.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
324 Vehicle Care
.Aftermarket appearance caps or covers
while the lamps are illuminated, due to
excessive heat generated
Caution
Failure to clean lamps properly can cause
damage to the lamp cover that would
not be covered by the vehicle warranty.
Caution
Using wax on low gloss black finish
stripes can increase the gloss level and
create a non-uniform finish. Clean low
gloss stripes with soap and water only.
Air Intakes
Clear debris from the air intakes, between
the hood and windshield, when washing the
vehicle.
Shutter System
The vehicle may have a shutter system
designed to help improve fuel economy.
Keep the shutter system clear of debris,
snow and ice. If the check engine light is
activated, please check to see if the shutter
system is clear of debris, snow or ice.
Windshield and Wiper Blades
Clean the outside of the windshield with
glass cleaner.
Clean rubber blades using a lint-free cloth or
paper towel soaked with windshield washer
fluid or a mild detergent. Wash the
windshield thoroughly when cleaning theblades. Bugs, road grime, sap, and a buildup
of vehicle wash/wax treatments may cause
wiper streaking.
Replace the wiper blades if they are worn or
damaged. Damage can be caused by
extreme dusty conditions, sand, salt, heat,
sun, snow, and ice.
Weatherstrips
Apply weatherstrip lubricant to
weatherstrips to make them last longer, seal
better, and not stick or squeak. Lubricate
weatherstrips at least once a year. Hot, dry
climates may require more frequent
application. Black marks from rubber
material on painted surfaces can be removed
by rubbing with a clean cloth. See
Recommended Fluids and Lubricants
0339.
Tires
Use a stiff brush with tire cleaner to clean
the tires.
Caution
Using petroleum-based tire dressing
products on the vehicle may damage the
paint finish and/or tires. When applying a
(Continued)

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Service and Maintenance 337
.Trained dealer technicians have the
diagnostic equipment to test the battery
and ensure that the connections and
cables are corrosion-free.
Belts
.Belts may need replacing if they squeak
or show signs of cracking or splitting.
.Trained dealer technicians have access to
tools and equipment to inspect the belts
and recommend adjustment or
replacement when necessary.
Brakes
Brakes stop the vehicle and are crucial to
safe driving.
.Signs of brake wear may include chirping,
grinding, or squealing noises, or difficulty
stopping.
.Trained dealer technicians have access to
tools and equipment to inspect the brakes
and recommend quality parts engineered
for the vehicle.
Fluids
Proper fluid levels and approved fluids
protect the vehicle’s systems and
components. See Recommended Fluids and
Lubricants 0339 for GM approved fluids.
.Engine oil and windshield washer fluid
levels should be checked at every fuel fill.
.Instrument cluster lights may come on to
indicate that fluids may be low and need
to be filled.
Hoses
Hoses transport fluids and should be
regularly inspected to ensure that there are
no cracks or leaks. With a multi-point
inspection, your dealer can inspect the hoses
and advise if replacement is needed.
Lamps
Properly working headlamps, taillamps, and
brake lamps are important to see and be
seen on the road.
.Signs that the headlamps need attention
include dimming, failure to light, cracking,
or damage. The brake lamps need to be
checked periodically to ensure that they
light when braking.
.With a multi-point inspection, your dealer
can check the lamps and note any
concerns. Shocks and Struts
Shocks and struts help aid in control for a
smoother ride.
.Signs of wear may include steering wheel
vibration, bounce/sway while braking,
longer stopping distance, or uneven
tire wear.
.As part of the multi-point inspection,
trained dealer technicians can visually
inspect the shocks and struts for signs of
leaking, blown seals, or damage, and can
advise when service is needed.
Tires
Tires need to be properly inflated, rotated,
and balanced. Maintaining the tires can save
money and fuel, and can reduce the risk of
tire failure.
.Signs that the tires need to be replaced
include three or more visible treadwear
indicators; cord or fabric showing through
the rubber; cracks or cuts in the tread or
sidewall; or a bulge or split in the tire.
.Trained dealer technicians can inspect and
recommend the right tires. Your dealer
can also provide tire/wheel balancing
services to ensure smooth vehicle
operation at all speeds. Your dealer sells
and services name brand tires.