2021 GMC ACADIA service

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
214 Driving and Operating
If the vehicle cannot be pulled over, and
must be shut off while driving, press and
hold ENGINE START/STOP for longer than
two seconds, or press twice in five seconds.
ACC/ACCESSORY (Amber Indicator Light) :
This mode allows some electrical accessories
to be used when the engine is off.
With the ignition off, pressing the button
one time without the brake pedal applied
will place the ignition system in ACC/
ACCESSORY.
The ignition will switch from ACC/
ACCESSORY to off after five minutes to
prevent battery rundown.
ON/RUN/START (Green Indicator Light) :This
mode is for driving and starting. With the
ignition off, and the brake pedal applied,
pressing the button once will place the
ignition system in ON/RUN/START. Once
engine cranking begins, release the button.
Engine cranking will continue until the
engine starts. See Starting the Engine 0214.
The ignition will then remain in ON/RUN.
Service Mode
This power mode is available for service and
diagnostics, and to verify the proper
operation of the malfunction indicator lamp
as may be required for emission inspection purposes. With the vehicle off, and the
brake pedal not applied, pressing and
holding the button for more than
five seconds will place the vehicle in Service
Mode. The instruments and audio systems
will operate as they do in ON/RUN, but the
vehicle will not be able to be driven. The
engine will not start in Service Mode. Press
the button again to turn the vehicle off.
Starting the Engine
Shift the vehicle into P (Park) or N (Neutral).
To restart the engine when the vehicle is
already moving, use N (Neutral) only.
Caution
Do not try to shift to P (Park) if the
vehicle is moving. If you do, you could
damage the transmission. Shift to P (Park)
only when the vehicle is stopped.
Caution
If you add electrical parts or accessories,
you could change the way the engine
operates. Any resulting damage would
not be covered by the vehicle warranty.
See
Add-On Electrical Equipment 0266.
Starting Procedure
1. With the Keyless Access system, the RKE
transmitter must be in the vehicle. Press
ENGINE START/STOP with the brake pedal
applied. When the engine begins
cranking, let go of the button.
The idle speed will go down as the
engine gets warm. Do not race the
engine immediately after starting it.
If the RKE transmitter is not in the
vehicle, if there is interference, or if the
RKE battery is low, the Driver
Information Center (DIC) will display a
message.
Caution
Cranking the engine for long periods of
time, by trying to start the engine
immediately after cranking has ended,
can overheat and damage the cranking
motor, and drain the battery. Wait at
least 15 seconds between each try, to let
the cranking motor cool down.
2. If the engine does not start after five to 10 seconds, especially in very cold
weather (below −18 °C or 0 °F), it could
be flooded with too much gasoline. Try
pushing the accelerator pedal all the way

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
218 Driving and Operating
able to release the EPB using the EPB
switch. It should automatically release when
the vehicle is shifted out of P (Park).
Leaving the Vehicle with the Engine
Running
{Warning
It can be dangerous to leave the vehicle
with the engine running. It could
overheat and catch fire.
It is dangerous to get out of the vehicle
if the vehicle is not in P (Park) with the
parking brake set. The vehicle can roll.
Do not leave the vehicle when the engine
is running. If you have left the engine
running, the vehicle can move suddenly.
You or others could be injured. To be
sure the vehicle will not move, even
when you are on fairly level ground,
always set the parking brake and shift
the vehicle to P (Park). SeeShifting Into
Park 0217. If you are towing a trailer,
see Driving Characteristics and Towing
Tips 0256. If you have to leave the vehicle with the
engine running, the vehicle must be in
P (Park) with the parking brake set.
Confirm that the vehicle is in P (Park).
Torque Lock
Torque lock is when the weight of the
vehicle puts too much force on the parking
pawl in the transmission. This happens when
parking on a hill and shifting the
transmission into P (Park) is not done
properly and then it is difficult to shift out
of P (Park). To prevent torque lock, set the
parking brake and then shift into P (Park). To
find out how, see
“Shifting Into Park” listed
previously.
On certain steep grades, the transmission
will automatically set the parking brake to
prevent torque lock.
If torque lock does occur, the vehicle may
need to be pushed uphill by another vehicle
to relieve the parking pawl pressure, so you
can shift out of P (Park).
Shifting out of Park
This vehicle is equipped with an electronic
transmission. If the vehicle has an
uncharged battery or a battery with low
voltage, try charging or jump starting the
battery. See Jump Starting - North America
0 332.
To shift out of P (Park): 1. Ensure the engine is running.
2. Apply the brake pedal.
3. Press or pull the desired shift switch on the center stack.
The P indicator will turn white and the gear
indicator will turn red when the vehicle is
no longer in P (Park).
If the vehicle cannot shift from P (Park), a
Driver Information Center (DIC) message will
be displayed. Check that the ignitionis on,
the engine is running, and the brake pedal
is applied when you are attempting to shift
out of P (Park). If all of these are met but
the vehicle will not shift out of P (Park), see
your dealer for service.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 225
The Electric Parking Brake (EPB) can always
be applied, even if the vehicle is off. In case
of insufficient electrical power, the EPB
cannot be applied or released. To prevent
draining the battery, avoid unnecessary
repeated cycles of the EPB.
The system has a red parking brake status
light and an amber service parking brake
warning light. SeeElectric Parking Brake
Light 0109 and
Service Electric Parking Brake Light (Uplevel
and Midlevel Cluster Only) 0109. There are
also parking brake-related Driver Information
Center (DIC) messages.
Before leaving the vehicle, check the red
parking brake status light to ensure that the
parking brake is applied.
EPB Apply
To apply the EPB:
1. Be sure the vehicle is at a complete stop.
2. Press the EPB switch momentarily.
The red parking brake status light will flash
and then stay on once the EPB is fully
applied. If the red parking brake status light
flashes continuously, then the EPB is only partially applied or there is a problem with
the EPB. A DIC message will display. Release
the EPB and try to apply it again. If the
light does not come on, or keeps flashing,
have the vehicle serviced. Do not drive the
vehicle if the red parking brake status light
is flashing. See your dealer.
If the amber service parking brake warning
light is on, press the EPB switch. Continue to
hold the switch until the red parking brake
status light remains on. If the amber service
parking brake warning light is on, see your
dealer.
If the EPB is applied while the vehicle is
moving, the vehicle will decelerate as long
as the switch is pressed. If the switch is
pressed until the vehicle comes to a stop,
the EPB will remain applied.
The vehicle may automatically apply the EPB
in some situations when the vehicle is not
moving. This is normal, and is done to
periodically check the correct operation of
the EPB system, or at the request of other
safety functions that utilize the EPB.
If the EPB fails to apply, block the rear
wheels to prevent vehicle movement.
EPB Release
To release the EPB:
1. Turn the ignition on or to ACC/ACCESSORY.
2. Apply and hold the brake pedal.
3. Press the EPB switch momentarily.
The EPB is released when the red parking
brake status light is off.
If the amber service parking brake warning
light is on, release the EPB by pressing and
holding the EPB switch. Continue to hold the
switch until the red parking brake status
light is off. If either light stays on after
release is attempted, see your dealer.
Caution
Driving with the parking brake on can
overheat the brake system and cause
premature wear or damage to brake
system parts. Make sure that the parking
brake is fully released and the brake
warning light is off before driving.
If you are towing a trailer and parking on a
hill, see Driving Characteristics and Towing
Tips 0256.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
238 Driving and Operating
Curves in the Road
{Warning
On curves, ACC may not detect a vehicle
ahead in your lane. You could be startled
if the vehicle accelerates up to the set
speed, especially when following a vehicle
exiting or entering exit ramps. You could
lose control of the vehicle or crash. Do
not use ACC while driving on an entrance
or exit ramp. Always be ready to use the
brakes if necessary.
{Warning
On curves, ACC may respond to a vehicle
in another lane, or may not have time to
react to a vehicle in your lane. You could
crash into a vehicle ahead of you, or lose
control of your vehicle. Give extra
attention in curves and be ready to use
the brakes if necessary. Select an
appropriate speed while driving in curves.
ACC may operate differently in a sharp
curve. It may reduce the vehicle speed if the
curve is too sharp. ACC automatically slows the vehicle down while navigating the curve
and may increase speed out of the curve,
but will not exceed the set speed.
When following a vehicle and entering a
curve, ACC may not detect the vehicle ahead
and accelerate to the set speed. When this
happens, the vehicle ahead indicator will not
appear.
ACC may detect a vehicle that is not in your
lane and apply the brakes.ACC may occasionally provide an alert and/
or braking that is considered unnecessary.
It could respond to vehicles in different
lanes, signs, guardrails, and other stationary
objects when entering or exiting a curve.
This is normal operation. The vehicle does
not need service.
Other Vehicle Lane Changes
ACC will not detect a vehicle ahead until it
is completely in the lane. The brakes may
need to be manually applied.
Objects Not Directly in Front of Your Vehicle
The detection of objects in front of the
vehicle may not be possible if:
.The vehicle or object ahead is not within
your lane.
.The vehicle ahead is shifted, not centered,
or is shifted to one side of the lane.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 247
Unnecessary Alerts
FCA may provide unnecessary alerts for
turning vehicles, vehicles in other lanes,
objects that are not vehicles, or shadows.
These alerts are normal operation and the
vehicle does not need service.
Cleaning the System
If the FCA system does not seem to operate
properly, this may correct the issue:
.Clean the outside of the windshield in
front of the rearview mirror.
.Clean the entire front of the vehicle.
.Clean the headlamps.
Automatic Emergency
Braking (AEB)
If the vehicle has Forward Collision Alert
(FCA), it also has AEB, which includes
Intelligent Brake Assist (IBA). When the
system detects a vehicle ahead in your path
that is traveling in the same direction that
you may be about to crash into, it can
provide a boost to braking or automatically
brake the vehicle. This can help avoid or
lessen the severity of crashes when driving
in a forward gear. Depending on the
situation, the vehicle may automaticallybrake moderately or hard. This automatic
emergency braking can only occur if a
vehicle is detected. This is shown by the FCA
vehicle ahead indicator being lit. See
Forward Collision Alert (FCA) System
0245.
The system works when driving in a forward
gear between 8 km/h (5 mph) and 80 km/h
(50 mph), or on vehicles with Adaptive
Cruise Control (ACC), above 4 km/h (2 mph).
It can detect vehicles up to approximately
60 m (197 ft).
{Warning
AEB is an emergency crash preparation
feature and is not designed to avoid
crashes. Do not rely on AEB to brake the
vehicle. AEB will not brake outside of its
operating speed range and only responds
to detected vehicles.
AEB may not:
.Detect a vehicle ahead on winding or
hilly roads.
.Detect all vehicles, especially vehicles
with a trailer, tractors, muddy
vehicles, etc. (Continued)
Warning (Continued)
.Detect a vehicle when weather limits
visibility, such as in fog, rain, or snow.
.Detect a vehicle ahead if it is partially
blocked by pedestrians or other
objects.
Complete attention is always required
while driving, and you should be ready to
take action and apply the brakes and/or
steer the vehicle to avoid crashes.
AEB may slow the vehicle to a complete
stop to try to avoid a potential crash. If this
happens, AEB may engage the Electric
Parking Brake (EPB) to hold the vehicle at a
stop. Release the EPB or firmly press the
accelerator pedal.
{Warning
AEB may automatically brake the vehicle
suddenly in situations where it is
unexpected and undesired. It could
respond to a turning vehicle ahead,
guardrails, signs, and other non-moving
objects. To override AEB, firmly press the
accelerator pedal, if it is safe to do so.

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
248 Driving and Operating
Intelligent Brake Assist (IBA)
IBA may activate when the brake pedal is
applied quickly by providing a boost to
braking based on the speed of approach and
distance to a vehicle ahead.
Minor brake pedal pulsations or pedal
movement during this time is normal and
the brake pedal should continue to be
applied as needed. IBA will automatically
disengage only when the brake pedal is
released.
{Warning
IBA may increase vehicle braking in
situations when it may not be necessary.
You could block the flow of traffic. If this
occurs, take your foot off the brake pedal
and then apply the brakes as needed.
AEB and IBA can be disabled through vehicle
personalization. See “Collision/Detection
Systems” underVehicle Personalization
0 123.
{Warning
Using AEB or IBA while towing a trailer
could cause you to lose control of the
vehicle and crash. Turn the system to
Alert, or if the vehicle has ACC to Off,
when towing a trailer.
A system unavailable message may
display if:
.The front of the vehicle or windshield is
not clean.
.Heavy rain or snow is interfering with
object detection.
.There is a problem with the StabiliTrak/
Electronic Stability Control (ESC) system.
The AEB system does not need service.
Front Pedestrian Braking (FPB)
System
If equipped, the FPB system may help avoid
or reduce the harm caused by front-end
crashes with nearby pedestrians when
driving in a forward gear. FPB displays an
amber indicator,
~, when a nearby
pedestrian is detected ahead. When
approaching a detected pedestrian too
quickly, FPB provides a red flashing alert on the windshield and rapidly beeps or pulses
the driver seat. FPB can provide a boost to
braking or automatically brake the vehicle.
This system includes Intelligent Brake Assist
(IBA), and the Automatic Emergency Braking
(AEB) system may also respond to
pedestrians. See
Automatic Emergency
Braking (AEB) 0247.
The FPB system can detect and alert to
pedestrians in a forward gear at speeds
between 8 km/h (5 mph) and 80 km/h
(50 mph). During daytime driving, the
system detects pedestrians up to a distance
of approximately 40 m (131 ft). During
nighttime driving, system performance is
very limited.
{Warning
FPB does not provide an alert or
automatically brake the vehicle, unless it
detects a pedestrian. FPB may not detect
pedestrians, including children:
.When the pedestrian is not directly
ahead, fully visible, or standing
upright, or when part of a group. (Continued)

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
250 Driving and Operating
Warning (Continued)
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 0123.
{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
LCA warning display will light up in the
corresponding outside mirror and will flash
if the turn signal is on.
{Warning
LCA does not alert the driver to vehicles
outside of the system detection zones,
pedestrians, bicyclists, or animals. It may
not provide alerts when changing lanes
under all driving conditions. Failure to use
(Continued)
Warning (Continued)
proper care when changing lanes may
result in injury, death, or vehicle damage.
Before making a lane change, always
check mirrors, glance over your shoulder,
and use the turn signals.
LCA Detection Zones
1. SBZA Detection Zone
2. LCA Detection Zone
The LCA sensor covers a zone of
approximately one lane over from both
sides of the vehicle, or 3.5 m (11 ft). The
height of the zone is approximately between
0.5 m (1.5 ft) and 2 m (6 ft) off the ground.
The Side Blind Zone Alert (SBZA) warning
area starts at approximately the middle of
the vehicle and goes back 5 m (16 ft). Drivers

GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 251
are also warned of vehicles rapidly
approaching from up to 70 m (230 ft) behind
the vehicle.
How the System Works
The LCA symbol lights up in the outside
mirrors when the system detects a moving
vehicle in the next lane over that is in the
side blind zone or rapidly approaching that
zone from behind. A lit LCA symbol indicates
it may be unsafe to change lanes. Before
making a lane change, check the LCA
display, check mirrors, glance over your
shoulder, and use the turn signals.
Left Outside MirrorDisplayRight Outside Mirror Display
When the vehicle is started, both outside
mirror LCA displays will briefly come on to
indicate the system is operating. When the
vehicle is in a forward gear, the left or right
outside mirror display will light up if a
moving vehicle is detected in the next lane
over in that blind zone or rapidly approaching that zone. If the turn signal is
activated in the same direction as a
detected vehicle, this display will flash as an
extra warning not to change lanes.
LCA can be disabled through vehicle
personalization. When you disable LCA, Side
Blind Zone Alert is also disabled. See
“Collision/Detection Systems”
underVehicle
Personalization 0123. If LCA is disabled by
the driver, the LCA mirror displays will not
light up.
When the System Does Not Seem to
Work Properly
The LCA system requires some driving for
the system to calibrate to maximum
performance. This calibration may occur
more quickly if the vehicle is driving on a
straight highway road with traffic and
roadside objects (e.g., guardrails, barriers).
LCA displays may not come on when
passing a vehicle quickly, for a stopped
vehicle, or when towing a trailer. 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. 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" under
Exterior Care0337. If the DIC
still 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.