2021 GMC ACADIA brakes

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 205
When driving on hills:
.Use a low gear and keep a firm grip on
the steering wheel.
.Maintain a slow speed.
.When possible, drive straight up or down
the hill.
.Slow down when approaching the top of
the hill.
.Use headlamps even during the day to
make the vehicle more visible.
{Warning
Driving to the top of a hill at high speed
can cause a crash. There could be a
drop-off, embankment, cliff, or even
another vehicle. You could be seriously
injured or killed. As you near the top of a
hill, slow down and stay alert.
.Never go downhill forward or backward
with the transmission in N (Neutral). The
brakes could overheat and you could lose
control.
.When driving down a hill, keep the
vehicle headed straight down. Use a low
gear because the engine will work with
the brakes to slow the vehicle and help
keep the vehicle under control.
{Warning
Heavy braking when going down a hill
can cause your brakes to overheat and
fade. This could cause loss of control and
you or others could be injured or killed.
Apply the brakes lightly when descending
a hill and use a low gear to keep vehicle
speed under control.
If the vehicle stalls on a hill: 1. Apply the brakes to stop the vehicle, and then apply the parking brake.
2. Shift into P (Park) and then restart the engine.
.If driving uphill when the vehicle
stalls, shift to R (Reverse), release the
parking brake, and back
straight down.
.Never try to turn the vehicle around.
If the hill is steep enough to stall the
vehicle, it is steep enough to cause it
to roll over.
.If you cannot make it up the hill,
back straight down the hill.
.Never back down a hill in N (Neutral)
using only the brake.
.The vehicle can roll backward quickly
and you could lose control.
.If driving downhill when the vehicle
stalls, shift to a lower gear, release
the parking brake, and drive straight
down the hill.
3. If the vehicle cannot be restarted after stalling, set the parking brake, shift into
P (Park), and turn the vehicle off.
3.1. Leave the vehicle and seek help.
3.2. Stay clear of the path the vehicle
would take if it rolled downhill.
.Avoid turns that take the vehicle across
the incline of the hill. A hill that can be
driven straight up or down might be too
steep to drive across. Driving across an
incline puts more weight on the downhill
wheels which could cause a downhill slide
or a rollover.
.Surface conditions can be a problem.
Loose gravel, muddy spots, or even wet
grass can cause the tires to slip sideways,
downhill. If the vehicle slips sideways, it
can hit something that will trip it —a
rock, a rut, etc. —and roll over.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
206 Driving and Operating
.Hidden obstacles can make the steepness
of the incline more severe. If a rock is
driven across with the uphill wheels, or if
the downhill wheels drop into a rut or
depression, the vehicle can tilt even more.
.If an incline must be driven across, and
the vehicle starts to slide, turn downhill.
This should help straighten out the
vehicle and prevent the side slipping.
{Warning
Getting out of the vehicle on the
downhill side when stopped across an
incline is dangerous. If the vehicle rolls
over, you could be crushed or killed.
Always get out on the uphill side of the
vehicle and stay well clear of the
rollover path.
Driving in Mud, Sand, Snow, or Ice
Use a low gear when driving in mud—the
deeper the mud, the lower the gear. Keep
the vehicle moving to avoid getting stuck.
Traction changes when driving on sand. On
loose sand, such as on beaches or sand
dunes, the tires tend to sink into the sand. This affects steering, accelerating, and
braking. Drive at a reduced speed and avoid
sharp turns or abrupt maneuvers.
Traction is reduced on hard packed snow
and ice and it is easy to lose control. Reduce
vehicle speed when driving on hard packed
snow and ice.
{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 might take longer to stop.
See Driving on Wet Roads 0207.
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.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 207
More frequent maintenance service is
required. SeeMaintenance Schedule 0346.
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
(Continued)
Warning (Continued)
ignore police warnings and be very
cautious about trying to drive through
flowing water.
Hydroplaning
Hydroplaning is dangerous. Water can build
up under the vehicle's tires so they actually
ride on the water. This can happen if the
road is wet enough and you are going fast
enough. When the vehicle is hydroplaning, it
has little or no contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to slow
down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet weather
driving tips include:
.Allow extra following distance.
.Pass with caution.
.Keep windshield wiping equipment in
good shape.
.Keep the windshield washer fluid reservoir
filled.
.Have good tires with proper tread depth.
SeeTires 0300.
.Turn off cruise control.
.Activate All-Wheel Drive (AWD) mode. See
Driver Mode Control 0228.
Hill and Mountain Roads
Driving on steep hills or through mountains
is different than driving on flat or rolling
terrain. Tips include:
.Keep the vehicle serviced and in good
shape.
.Check all fluid levels, brakes, tires, cooling
system, and transmission.
.Shift to a lower gear when going down
steep or long hills.
{Warning
Using the brakes to slow the vehicle on a
long downhill slope can cause brake
overheating, can reduce brake
performance, and could result in a loss of
braking. Shift the transmission to a lower
gear to let the engine assist the brakes
on a steep downhill slope.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
208 Driving and Operating
{Warning
Coasting downhill in N (Neutral) or with
the ignition off is dangerous. This can
cause overheating of the brakes and loss
of steering assist. Always have the engine
running and the vehicle in gear.
.Drive at speeds that keep the vehicle in
its own lane. Do not swing wide or cross
the center line.
.Be alert on top of hills; something could
be in your lane (e.g., stalled car, crash).
.Pay attention to special road signs
(e.g., falling rocks area, winding roads,
long grades, passing or no-passing zones)
and take appropriate action.
Winter Driving
Driving on Snow or Ice
Snow or ice between the tires and the road
creates less traction or grip, so drive
carefully. Wet ice can occur at about 0 °C
(32 °F) when freezing rain begins to fall.
Avoid driving on wet ice or in freezing rain
until roads can be treated.For Slippery Road Driving:
.Accelerate gently. Accelerating too quickly
causes the wheels to spin and makes the
surface under the tires slick.
.Turn on Traction Control. See
Traction
Control/Electronic Stability Control 0226.
.The Antilock Brake System (ABS) improves
vehicle stability during hard stops, but
the brakes should be applied sooner than
when on dry pavement. See Antilock
Brake System (ABS) 0224.
.Allow greater following distance and
watch for slippery spots. Icy patches can
occur on otherwise clear roads in shaded
areas. The surface of a curve or an
overpass can remain icy when the
surrounding roads are clear. Avoid sudden
steering maneuvers and braking while
on ice.
.Turn off cruise control.
.Select All-Wheel Drive (AWD) Mode for
vehicles equipped with AWD. Select
Snow/Ice Mode for FWD only vehicles.
See Driver Mode Control 0228 and
All-Wheel Drive 0224.
Blizzard Conditions
Stop the vehicle in a safe place and signal
for help. Stay with the vehicle unless there
is help nearby. If possible, use Roadside
Assistance. See Roadside Assistance Program
0 366. To get help and keep everyone in
the vehicle safe:
.Turn on the hazard warning flashers.
.Tie a red cloth to an outside mirror.
{Warning
Snow can trap engine exhaust under the
vehicle. This may cause exhaust gases to
get inside. Engine exhaust contains
carbon monoxide (CO), which cannot be
seen or smelled. It can cause
unconsciousness and even death.
If the vehicle is stuck in snow:
.Clear snow from the base of the
vehicle, especially any blocking the
exhaust pipe.
.Open a window about 5 cm (2 in) on
the vehicle side that is away from the
wind, to bring in fresh air.
.Fully open the air outlets on or under
the instrument panel.
(Continued)

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 213
Caution (Continued)
.Avoid making hard stops for the first
300 km (200 mi) or so. During this
time the new brake linings are not yet
broken in. Hard stops with new linings
can mean premature wear and earlier
replacement. Follow this breaking-in
guideline every time you get new
brake linings.
Following break-in, engine speed and load
can be gradually increased.
Ignition Positions
The vehicle has an electronic keyless ignition
with pushbutton start. The Remote Keyless Entry (RKE) transmitter
must be in the vehicle for the system to
operate. If the pushbutton start is not
working, the vehicle may be near a strong
radio antenna signal causing interference to
the Remote Keyless Entry (RKE) system. See
Remote Keyless Entry (RKE) System
Operation
07.
To shift out of P (Park), the vehicle must be
on and the brake pedal must be applied.
Stopping the Engine/LOCK/OFF (No Indicator
Lights) : When the vehicle is stopped, press
ENGINE START/STOP once to turn the
engine off.
If the vehicle is in P (Park), the ignition will
turn off, and Retained Accessory Power (RAP)
will remain active. See Retained Accessory
Power (RAP) 0217.
If the vehicle is in R (Reverse), D (Drive) or
L (Low), the vehicle will shift to P (Park), the
ignition will turn off, and Retained Accessory
Power (RAP) will remain active. If the vehicle
is in N (Neutral), the ignition will return to
ACC/ACCESSORY and display the message
SHIFT TO PARK in the Driver Information
Center (DIC). When the vehicle is shifted
into P (Park), the ignition will turn off. Do not turn the engine off when the vehicle
is moving. This will cause a loss of power
assist in the brake and steering systems and
disable the airbags.
If the vehicle must be shut off in an
emergency:
1. Brake using a firm and steady pressure. Do not pump the brakes repeatedly. This
may deplete power assist, requiring
increased brake pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the vehicle is moving.
After shifting to N (Neutral), firmly apply
the brakes and steer the vehicle to a
safe location.
3. Come to a complete stop and shift to P (Park).
4. Set the parking brake. See Electric
Parking Brake 0224. And press ENGINE
START/STOP to turn the vehicle off.
{Warning
Turning off the vehicle while moving may
cause loss of power assist in the brake
and steering systems and disable the
airbags. While driving, only shut the
vehicle off in an emergency.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 215
to the floor and holding it there as you
press ENGINE START/STOP, for up to a
maximum of 15 seconds. Wait at least
15 seconds between each try, to allow
the cranking motor to cool down. When
the engine starts, let go of the button
and the accelerator. If the vehicle starts
briefly but then stops again, do the
same thing. This clears the extra gasoline
from the engine. Do not race the engine
immediately after starting it. Operate
the engine and transmission gently until
the oil warms up and lubricates all
moving parts.
Stop/Start System
The Stop/Start system will shut off the
engine to help conserve fuel. It has
components designed for the increased
number of starts.
{Warning
The automatic engine Stop/Start feature
causes the engine to shut off while the
vehicle is still on. Do not exit the vehicle
before shifting to P (Park). The vehicle
may restart and move unexpectedly.
Always shift to P (Park), and then turn
the ignition off before exiting the vehicle.Auto Engine Stop/Start
When the brakes are applied and the vehicle
is at a complete stop, the engine may turn
off. When stopped, the tachometer displays
AUTO STOP. See
Tachometer0102. When
the brake pedal is released or the
accelerator pedal is pressed, the engine will
restart.
To maintain vehicle performance, other
conditions may cause the engine to
automatically restart before the brake pedal
is released.
Auto Stops may not occur and/or auto
restarts may occur because:
.The climate control settings require the
engine to be running to cool or heat the
vehicle interior.
.The vehicle battery charge is low.
.The vehicle battery has recently been
disconnected.
.Minimum vehicle speed has not been
reached since the last Auto Stop
.The accelerator pedal is pressed.
.The engine or transmission is not at the
required operating temperature.
.The outside temperature is not in the
required operating range.
.The transmission is shifted out of
D (Drive) to any gear other than P (Park).
.Tow/Haul Mode or other driver modes
have been selected.
.The vehicle is on a steep hill or grade.
.The driver door has been opened or driver
seat belt has been unbuckled.
.The hood has been opened.
.The Auto Stop has reached the maximum
allowed time.
Auto Stop/Start Disable Switch
The automatic engine Stop/Start feature can
be disabled and enabled by pressing
h.
Auto Stop/Start is enabled each time you
start the vehicle.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 223
D :This position is for normal driving.
If more power is needed for passing, press
the accelerator pedal down.
To shift into D (Drive):
1. Bring the vehicle to a complete stop.
2. Pull the D (Drive) switch on the center stack.
To shift out of D (Drive): 1. Bring the vehicle to a complete stop.
2. Shift to the desired gear.
Downshifting the transmission in slippery
road conditions could result in skidding. See
“Skidding” underLoss of Control 0203.
Caution
Spinning the tires or holding the vehicle
in one place on a hill using only the
accelerator pedal may damage the
transmission. The repair will not be
covered by the vehicle warranty. If the
vehicle is stuck, do not spin the tires.
When stopping on a hill, use the brakes
to hold the vehicle in place. If equipped with the 2.0L L4 engine, engine
speeds may be increased while driving at
highway speeds while the engine is still
warming up.
L :
This position gives you access to gear
ranges. This provides more engine braking
but lower fuel economy than D (Drive). You
can use it on very steep hills, or in deep
snow or mud. See Manual Mode0223.
Manual Mode
Electronic Range Select (ERS) Mode
ERS or manual mode allows for the selection
of the range of gear positions. Use this
mode when driving downhill or towing a
trailer to limit the top gear and vehicle speed. The shift position indicator within the
Driver Information Center (DIC) will display a
number next to the L indicating the highest
available gear under manual mode and the
driving conditions when manual mode was
selected.
To use this feature:
1. With the vehicle in D (Drive), press the L (Low) button.
2. Press the plus or minus button on the center stack to increase or decrease the
gear range available.
When shifting to L (Low), the transmission
will shift to a preset lower gear range. For
this preset range, the highest gear available
is displayed next to the L in the DIC. See
Driver Information Center (DIC) (Base) 0115
or
Driver Information Center (DIC) (Midlevel and
Uplevel) 0117. All gears below that number
are available to use. For example, when
4 (Fourth) is shown next to the L, 1 (First)
through 4 (Fourth) gears are shifted
automatically. To shift to 5 (Fifth) gear, press
the + (Plus) button or shift into D (Drive).
L (Low) will prevent shifting to a lower gear
range if the engine speed is too high.
If vehicle speed is not reduced within the

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
224 Driving and Operating
time allowed, the lower gear range shift will
not be completed. Slow the vehicle, then
press the−(Minus) button to the desired
lower gear range.
While using ERS, cruise control can be used.
Tow/Haul Mode
See Driver Mode Control 0228.
Drive Systems
All-Wheel Drive
Vehicles with this feature can operate in
AWD Mode. See Driver Mode Control 0228.
Brakes
Electric Brake Boost
Vehicles equipped with electric brake boost
have hydraulic brake circuits that are
electronically controlled when the brake
pedal is applied during normal operation.
The system performs routine tests and turns
off within a few minutes after the vehicle is
turned off. Noise may be heard during this
time. If the brake pedal is pressed during the tests or when the electric brake boost
system is off, a noticeable change in pedal
force and travel may be felt. This is normal.
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 0110.
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