brake GMC ACADIA 2020 Repair Manual

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Driving and Operating 247
.Vehicles can tow in D (Drive).
Tow/Haul Mode is recommended
for heavier trailers. See Tow/
Haul Mode 0206. If the
transmission downshifts too
often, a lower gear may be
selected using Manual Mode.
See Manual Mode 0205.
If equipped, the following driver
assistance features should be
turned off when towing a trailer:
. Adaptive Cruise Control (ACC)
. Super Cruise Control
. Lane Keep Assist (LKA)
. Park Assist
. Automatic Parking Assist (APA)
. Reverse Automatic
Braking (RAB)
If equipped, the following driver
assistance features should be
turned to alert or off when towing a
trailer:
. Automatic Emergency
Braking (AEB)
. Intelligent Brake Assist (IBA)
. Front Pedestrian Braking (FPB) If equipped with Lane Change Alert
(LCA), the LCA detection zones that
extend back from the side of the
vehicle do not move further back
when a trailer is towed. Use caution
while changing lanes when towing a
trailer.
If equipped with Rear Cross Traffic
Alert (RCTA), use caution while
backing up when towing a trailer, as
the RCTA detection zones that
extend out from the back of the
vehicle do not move further back
when a trailer is towed.
{Warning
To prevent serious injury or death
from carbon monoxide (CO),
when towing a trailer:
. Do not drive with the
liftgate, trunk/hatch,
or rear-most window open.
. Fully open the air outlets on
or under the instrument
panel.
(Continued)
Warning (Continued)
.Adjust the climate control
system to a setting that
brings in only outside air.
See “Climate Control
Systems” in the Index.
For more information about
carbon monoxide, see Engine
Exhaust 0200.
Towing a trailer requires experience.
The combination of the vehicle and
trailer is longer and not as
responsive as the vehicle itself. Get
used to the handling and braking of
the combination by driving on a
level road surface before driving on
public roads.
The trailer structure, the tires, and
the brakes must be all be rated to
carry the intended cargo.
Inadequate trailer equipment can
cause the combination to operate in
an unexpected or unsafe manner.
Before driving, inspect all trailer
hitch parts and attachments, safety
chains, electrical connectors, lamps,

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
248 Driving and Operating
tires, and mirrors. SeeTowing
Equipment 0253. If the trailer has
electric brakes, start the
combination moving and then
manually apply the trailer brake
controller to check the trailer brakes
work. During the trip, occasionally
check that the cargo and trailer are
secure and that the lamps and any
trailer brakes are working.
Towing with a Stability Control
System
When towing, the stability control
system might be heard. The system
reacts to vehicle movement caused
by the trailer, which mainly occurs
during cornering. This is normal
when towing heavier trailers.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving without a trailer. This can
help to avoid heavy braking and
sudden turns.
Passing
More passing distance is needed
when towing a trailer. The
combination of the vehicle and
trailer will not accelerate as quickly
and is much longer than the vehicle
alone. It is necessary to go much
farther beyond the passed vehicle
before returning to the lane. Pass
on level roadways. Avoid passing
on hills if possible.
Backing Up
Hold the bottom of the steering
wheel with one hand. To move the
trailer to the left, move that hand to
the left. To move the trailer to the
right, move that hand to the right.
Always back up slowly and,
if possible, have someone
guide you.
Making Turns
Caution
Turn more slowly and make wider
arcs when towing a trailer to
prevent damage to your vehicle.
Making very sharp turns could
cause the trailer to contact the
vehicle.
Make wider turns than normal when
towing, so the 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.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Driving and Operating 249
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, see
Engine Overheating0279.
Viewing Systems
If equipped, the viewing systems on
the vehicle can improve visibility
while hitching, backing, and driving
with a trailer. See Driver Assistance
Systems 0225 and
Assistance Systems for Parking or
Backing 0227.
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 0353. It is
especially important to check the
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.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
250 Driving and Operating
Engine Cooling When Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. SeeEngine Overheating
0 279.
Trailer Towing
Caution
Towing a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To tow a trailer
correctly, follow the directions in
this section and see your dealer
for important information about
towing a trailer with the vehicle.
Trailer Weight
{Warning
Never exceed the towing capacity
for your vehicle.
Safe trailering requires monitoring
the weight, speed, altitude, road
grades, outside temperature,
dimensions of the front of the trailer,
and how frequently the vehicle is
used to tow a trailer.
Trailer Weight Ratings
When towing a trailer, the weight of
the loaded vehicle and trailer must
be within the weight ratings for the
vehicle.
. GCWR: Gross Combined Weight
Rating
. GVWR: Gross Vehicle Weight
Rating
. Maximum Trailer Weight Rating
. Maximum Trailer Tongue Weight The only way to be sure the weight
is not exceeding any of these
ratings is to weigh the tow vehicle
and trailer combination, fully loaded
for the trip, getting individual
weights for each of these items.
{Warning
You and others could be seriously
injured or killed if the trailer is too
heavy or the trailer brakes are
inadequate for the load. The
vehicle may be damaged, and the
repairs would not be covered by
the vehicle warranty.
Only tow a trailer if all the steps in
this section have been followed.
Ask your dealer for advice and
information about towing a trailer.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Driving and Operating 255
Trailer Brakes
Loaded trailers over 450 kg
(1,000 lb) must be equipped with
brake systems and with brakes for
each axle. Trailer braking equipment
conforming to Canadian Standards
Association (CSA) requirement
CAN3-D313, or its equivalent, is
recommended.
State or local regulations may
require trailers to have their own
braking system if the loaded weight
of the trailer exceeds certain
minimums that can vary from state
to state. Read and follow the
instructions for the trailer brakes so
they are installed, adjusted, and
maintained properly. Never attempt
to tap into your vehicle's hydraulic
brake system. If you do, both the
vehicle anti-lock brakes and the
trailer brakes may not function,
which could result in a crash.
Trailer Wiring Harness
lf equipped, the trailer wiring
harness, with a 7-pin connector is
mounted on the trailer hitch.
1. Left Turn/Brake
2. Tail Lamps
3. Reverse Lamps
4. Battery feed
5. Right Turn/Brake
6. Electric Brakes
7. Ground
If the vehicle is not equipped with a
trailer connector on the trailer hitch,
a 7-wire trailering harness is tied to
the vehicles frame. The harness
requires the installation of a trailer
connector, which is available
through your dealer.Use only a round, seven-wire
connector with flat blade terminals
meeting SAE J2863 specifications
for proper electrical connectivity.
The seven-wire harness contains
the following trailer circuits:
Stop/Turn
Signal Left Yellow/Gray
Stop/Turn
Signal Right Green/Violet
Tail/Parking
Lamps Gray/Brown
Reverse Lamps White/Green
Battery Feed Red/Green
Ground Black
Electric Trailer
Brake Blue
Electric Brake Control Wiring
Provisions
If equipped, (4) blunt-cut wires are
located near the driver's feet for an
aftermarket electric trailer brake
controller as part of the trailer wiring
package. The harness contains the
following circuits:

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
256 Driving and Operating
Electric Trailer
BrakesBlue
Battery Feed Red/Black or
Red/Blue
Brake Apply
Signal White/Blue
Ground Black
Refer to the aftermarket electric
trailer brake controller owner's
manual to determine wire color
coding of the electric trailer brake
controller. The wire colors on the
brake controller may be different
from the vehicle. It may be
necessary to have a technician
connect the 12-volt power to the
engine compartment fuse block. The
electric trailer brake controller
should be installed by your dealer or
a qualified service center.
Trailer Lamps
Always check all trailer lamps are
working at the beginning of each
trip, and periodically on longer trips.
Turn Signals When Towing a
Trailer
When properly connected, the trailer
turn signals should will illuminate to
indicate the vehicle is turning,
changing lanes, or stopping. When
towing a trailer, the arrows on the
instrument cluster will illuminate
even if the trailer is not properly
connected or the bulbs are
burned out.
Tow/Haul Mode
For instructions on how to enter
Tow/Haul mode, see Driver Mode
Control 0212.
Tow/Haul assists when pulling a
heavy trailer or a large or heavy
load. See Tow/Haul Mode 0206.
Tow/Haul Mode is designed to be
most effective when the vehicle and
trailer combined weight is at least
75% of the vehicle's Gross
Combined Weight Rating (GCWR).
See “Weight of the Trailer” under
Trailer Towing 0250. Tow/Haul Mode is most useful when
towing a heavy trailer or carrying a
large or heavy load:
.
through rolling terrain
. in stop-and-go traffic
. in busy parking lots
Operating the vehicle in Tow/Haul
Mode when lightly loaded or not
towing will not cause damage;
however, it is not recommended and
may result in unpleasant engine and
transmission driving characteristics
and reduced fuel economy.
Trailer Sway
Control (TSC)
Vehicles with StabiliTrak/Electronic
Stability Control (ESC) have a
Trailer Sway Control (TSC) feature.
Trailer sway is unintended
side-to-side motion of a trailer while
towing. If the vehicle is towing a
trailer and the TSC detects that
sway is increasing, the vehicle
brakes are selectively applied at
each wheel, to help reduce
excessive trailer sway. If equipped
with the Integrated Trailer Brake

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Driving and Operating 257
Control (ITBC) system, and the
trailer has an electric brake system,
StabiliTrak/ESC may also apply the
trailer brakes.
If TSC is enabled, the Traction
Control System (TCS)/StabiliTrak/
ESC warning light will flash on the
instrument cluster. Reduce vehicle
speed by gradually removing your
foot from the accelerator. If trailer
sway continues, StabiliTrak/ESC
can reduce engine torque to help
slow the vehicle. TSC will not
function if StabiliTrak/ESC is turned
off. SeeTraction Control/Electronic
Stability Control 0209.
{Warning
Trailer sway can result in a crash
and in serious injury or death,
even if the vehicle is equipped
with TSC.
If the trailer begins to sway,
reduce vehicle speed by
gradually removing your foot from
the accelerator. Then pull over to
check the trailer and vehicle to
help correct possible causes,
including an improperly or
overloaded trailer, unrestrained
cargo, improper trailer hitch
configuration, or improperly
inflated or incorrect vehicle or
trailer tires. See Towing
Equipment 0253 for trailer ratings
and hitch setup
recommendations.
Trailer Tires
Special Trailer (ST) tires differ from
vehicle tires. Trailer tires are
designed with stiff sidewalls to help
prevent sway and to support heavy
loads. These features can make it
difficult to determine if the trailer tire
pressures are low only based on a
visual inspection.
Always check all trailer tire
pressures before each trip when the
tires are cool. Low trailer tire
pressure is a leading cause of trailer
tire blow-outs.
Trailer tires deteriorate over time.
The trailer tire sidewall will show the
week and year the tire was
manufactured. Many trailer tire
manufacturers recommend
replacing tires more than six
years old.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Vehicle Care 259
Vehicle Care
General Information
General Information . . . . . . . . . . 260
California Proposition65 Warning . . . . . . . . . . . . . . . . . 260
California Perchlorate Materials Requirements . . . . . 261
Accessories and Modifications . . . . . . . . . . . . . . . . 261
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 261
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 262
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 264
Engine Oil . . . . . . . . . . . . . . . . . . . . 269
Engine Oil Life System . . . . . . . 271
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . 272
Engine Air Filter Life System . . . . . . . . . . . . . . . . . . . . . . 273
Engine Air Cleaner/Filter . . . . . . 273
Cooling System . . . . . . . . . . . . . . 275
Engine Overheating . . . . . . . . . . 279
Washer Fluid . . . . . . . . . . . . . . . . . 281
Brakes . . . . . . . . . . . . . . . . . . . . . . . 281
Brake Fluid . . . . . . . . . . . . . . . . . . . 282 Battery - North America . . . . . . 283
All-Wheel Drive . . . . . . . . . . . . . . . 284
Starter Switch Check . . . . . . . . . 284
Park Brake and P (Park)
Mechanism Check . . . . . . . . . . 285
Wiper Blade Replacement . . . . 285
Windshield Replacement . . . . . 286
Gas Strut(s) . . . . . . . . . . . . . . . . . . 286
Headlamp Aiming
Front Headlamp Aiming . . . . . . 288
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 288
Halogen Bulbs . . . . . . . . . . . . . . . . 288
LED Lighting . . . . . . . . . . . . . . . . . 288
Electrical System
Electrical System Overload . . . 289
Fuses and Circuit Breakers . . . 289
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 290
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 293
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 295
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 297
All-Season Tires . . . . . . . . . . . . . . 298
Winter Tires . . . . . . . . . . . . . . . . . . 299
Summer Tires . . . . . . . . . . . . . . . . 299 Tire Sidewall Labeling . . . . . . . . 300
Tire Designations . . . . . . . . . . . . . 302
Tire Terminology and
Definitions . . . . . . . . . . . . . . . . . . 302
Tire Pressure . . . . . . . . . . . . . . . . . 305
Tire Pressure for High-Speed
Operation . . . . . . . . . . . . . . . . . . . 306
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . . . . . . 307
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . . . 308
Tire Inspection . . . . . . . . . . . . . . . . 312
Tire Rotation . . . . . . . . . . . . . . . . . 312
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . 313
Buying New Tires . . . . . . . . . . . . . 314
Different Size Tires and Wheels . . . . . . . . . . . . . . . . . . . . . . 315
Uniform Tire Quality Grading . . . . . . . . . . . . . . . . . . . . . 316
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . . . 317
Wheel Replacement . . . . . . . . . . 318
Tire Chains . . . . . . . . . . . . . . . . . . . 318
If a Tire Goes Flat . . . . . . . . . . . . 319
Tire Sealant and Compressor Kit . . . . . . . . . . . . . 321
Storing the Tire Sealant and Compressor Kit . . . . . . . . . . . . . 327
Tire Changing . . . . . . . . . . . . . . . . 328

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Vehicle Care 261
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.
Also, see
Adding Equipment to the
Airbag-Equipped Vehicle 076.
Vehicle Checks
Doing Your Own
Service Work
{Warning
It can be dangerous to work on
your vehicle if you do not have
the proper knowledge, service
manual, tools, or parts. Always
follow owner ’s manual procedures
and consult the service manual
for your vehicle before doing any
service work.
If doing some of your own service
work, use the proper service
manual. It tells you much more
about how to service the vehicle
than this manual can. To order the
proper service manual, see
Publication Ordering Information
0 379.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13687875) - 2020 - CRC - 10/28/19
Vehicle Care 265
1.Engine Air Cleaner/Filter 0273.
2. Engine Oil Fill Cap. See Engine Oil 0269.
3. Engine Oil Dipstick. See Engine Oil 0269.
4. Engine Cooling Fan (Out of View). See Cooling System
0 275.
5. Brake Fluid Reservoir. See Brake Fluid 0282. 6.
Battery - North America 0283.
7. Engine Coolant Surge Tank and Pressure Cap. See
Cooling System 0275.
8. Positive (+) Battery Terminal (Under Cover). See Jump
Starting - North America 0335. 9. Windshield Washer Fluid
Reservoir. See Washer Fluid
0 281.
10. Engine Compartment Fuse
Block 0290.
11. Remote Negative (-) Battery Terminal. See Jump Starting -
North America 0335.