GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
236 Driving and Operating
If ACC is engaged, driver action may be
required when ACC cannot apply sufficient
braking because of approaching a vehicle
too rapidly.
When this condition occurs, the collision
alert symbol will flash on the windshield.
Either eight beeps will sound from the front,
or both sides of the Safety Alert Seat will
pulse five times. See“Collision/Detection
Systems” underVehicle Personalization
0 123.
See Defensive Driving 0201.
Approaching and Following a Vehicle
The vehicle ahead indicator is in the
instrument cluster and HUD, if equipped.
The vehicle ahead indicator only displays
when a vehicle is detected in your vehicle’s
path moving in the same direction.
If this symbol is not displaying, ACC will not
respond to or brake for vehicles ahead. ACC automatically slows the vehicle down
and adjusts vehicle speed to follow the
vehicle in front at the selected follow gap.
The vehicle speed increases or decreases to
follow the vehicle in front of you, but will
not exceed the set speed. It may apply
limited braking, if necessary. When braking
is active, the brake lights will come on. The
automatic braking may feel or sound
different than if the brakes were applied
manually. This is normal.
Passing a Vehicle While Using ACC
If the set speed is high enough, and the left
turn signal is used to pass a vehicle ahead
in the selected following gap, ACC may
assist by gradually accelerating the vehicle
prior to the lane change.
{Warning
When using ACC to pass a vehicle or
perform a lane change, the following
distance to the vehicle being passed may
be reduced. ACC may not apply sufficient
acceleration or braking when passing a
vehicle or performing a lane change.
Always be ready to manually accelerate
or brake to complete the pass or lane
change.Stationary or Very Slow-Moving Objects
{Warning
ACC may not detect and react to stopped
or slow-moving vehicles ahead of you. For
example, the system may not brake for a
vehicle it has never detected moving. This
can occur in stop-and-go traffic or when a
vehicle suddenly appears due to a vehicle
ahead changing lanes. Your vehicle may
not stop and could cause a crash. Use
caution when using ACC. Your complete
attention is always required while driving
and you should be ready to take action
and apply the brakes.
Irregular Objects Affecting ACC
ACC may have difficulty detecting the
following objects:
.Vehicles with cargo extending from the
back end.
.Non-standard shaped vehicles, such as
vehicle transport, vehicles with a side car
fitted, or horse carriages.
.Objects that are close to the front of your
vehicle.
GMC Acadia/Acadia Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-14608671) - 2021 - CRC - 10/26/20
Driving and Operating 237
ACC Automatically Disengages
ACC may automatically disengage and the
driver will need to manually apply the
brakes to slow the vehicle when:
.The sensors are blocked.
.The Traction Control System (TCS) or
StabiliTrak/ESC system has activated or
been disabled.
.There is a fault in the system.
.The radar may falsely report a blockage
when driving in a desert or remote area
with no other vehicles or roadside objects.
.A DIC message may display to indicate
that ACC is temporarily unavailable.
The ACC indicator will turn white when ACC
is no longer active.
In some cases, when ACC is temporarily
unavailable, regular cruise control may be
used. See “Switching Between ACC and
Regular Cruise Control” in this section.
Always consider driving conditions before
using either cruise control system.
Notification to Resume ACC
ACC will maintain a follow gap behind a
detected vehicle and slow your vehicle to a
stop behind that vehicle. If the stopped vehicle ahead has driven
away and ACC has not resumed, the vehicle
ahead indicator will flash as a reminder to
check traffic ahead before proceeding. In
addition, the left and right sides of the
Safety Alert Seat will pulse three times,
or three beeps will sound. See
“Alert Type”
and “Adaptive Cruise Go Notifier” in
“Collision/Detection Systems” underVehicle
Personalization 0123.
When the vehicle ahead drives away, press
RES+ or the accelerator pedal to resume
cruise control. If stopped for more than
two minutes or if the driver door is opened
and the driver seat belt is unbuckled, the
ACC automatically applies the Electric
Parking Brake (EPB) to hold the vehicle. The
EPB status light will turn on. See Electric
Parking Brake 0224. To resume ACC and
release the EPB, press the accelerator pedal.
A DIC warning message may display
indicating to shift to P (Park) before exiting
the vehicle. See Vehicle Messages 0122.
{Warning
If ACC has stopped the vehicle, and if ACC
is disengaged, turned off, or canceled, the
vehicle will no longer be held at a stop.
(Continued)
Warning (Continued)
The vehicle can move. When ACC is
holding the vehicle at a stop, always be
prepared to manually apply the brakes.
{Warning
Leaving the vehicle without placing it in
P (Park) can be dangerous. Do not leave
the vehicle while it is being held at a
stop by ACC. Always place the vehicle in
P (Park) and turn off the ignition before
leaving the vehicle.
ACC Override
If using the accelerator pedal while ACC is
active, the ACC indicator turns blue on the
instrument cluster and HUD, if equipped.
ACC will resume operation when the
accelerator pedal is not being pressed.
{Warning
The ACC will not automatically apply the
brakes if your foot is resting on the
accelerator pedal. You could crash into a
vehicle ahead of you.
