2021 GMC TERRAIN brakes

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
218 Driving and Operating
The HDC light displays on the instrument
cluster when enabled.
HDC can maintain vehicle speeds between
3 and 22 km/h (2 and 14 mph) on an incline
greater than or equal to a 10% grade.
A blinking HDC light indicates the system is
actively applying the brakes to maintain
vehicle speed.
When HDC is activated, the initial HDC
speed is set to the current driving speed.
It can be increased or decreased by pressing
+RES or–SET on the steering wheel or by
applying the accelerator or brake pedal. This
adjusted speed becomes the new set speed.
HDC will remain enabled between 22 and
60 km/h (14 and 37 mph); however vehicle
speed cannot be set or maintained in this
range. It will automatically disable if the
vehicle speed is above 80 km/h (50 mph) or
above 60 km/h (37 mph) for at least
30 seconds. Press
5again to re-enable HDC.
Driver Mode Control
Depending on the option package and
available features, the Driver Mode Control
can have the following modes: Tour
(Front-Wheel Drive (FWD)), All-Wheel Drive
(AWD), Snow/Ice, Off-Road, and Tow/Haul.
Rotate the Driver Mode Control knob on the
center console to make a mode selection.
Continue turning the knob through the
available modes. Upon selection of a mode,
the selected mode’s icon will light up on the
knob and a message will be displayed in the
Driver Information Center (DIC).
Driver Mode Control Knob for Front-Wheel
Drive (FWD)
Driver Mode Control Knob for All-Wheel
Drive (AWD)
q(Vehicles without AWD) or5(AWD
equipped vehicles) Tour Mode : Use Tour
Mode during normal driving conditions. Tour
Mode either puts the vehicle in Front-Wheel
Drive (FWD) for AWD vehicles, or is the
normal drive mode for FWD vehicles. Tour
Mode is the most fuel efficient drive mode.
See Driving for Better Fuel Economy 0187.
When selecting Tour Mode, if equipped, the
AWD light will flash briefly while the
system disables, and then stays off.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Driving and Operating 221
automatically disengage. SeeTraction
Control/Electronic Stability Control 0214. If a
collision alert occurs when cruise control is
activated, cruise control is disengaged. See
Forward Collision Alert (FCA) System 0237.
When road conditions allow you to safely
use it again, cruise control can be turned
back on.
Cruise control will disengage if either TCS or
StabiliTrak/ESC is turned off.
If Hill Descent Control (HDC) is engaged,
cruise control disengages. See Hill Descent
Control (HDC) 0217.
If the brakes are applied, cruise control
disengages.5: Press to turn the cruise control system
on and off. A white indicator comes on in
the instrument cluster when cruise control is
turned on.
*: Press to disengage cruise control
without erasing the set speed from memory.
+RES : If there is a set speed in memory,
press briefly to resume that speed or press
and hold to accelerate. If cruise control is
already active, use to increase vehicle speed.
–SET : Press briefly to set the speed and
activate cruise control. If cruise control is
already active, use to decrease vehicle
speed.
Setting Cruise Control
If
5is on when not in use, –SET or +RES
could get bumped and go into cruise when
not desired. Keep
5off when cruise is not
being used.
To set a speed:
1. Press
5to turn the cruise system on.
2. Get up to the desired speed.
3. Press and release –SET. The desired set
speed briefly appears in the instrument
cluster. 4. Remove your foot from the accelerator
pedal.
The cruise control indicator on the
instrument cluster turns green after cruise
control has been set to the desired speed.
See Instrument Cluster (Base and Midlevel)
0 85 or
Instrument Cluster (Uplevel) 088.
Resuming a Set Speed
If the cruise control is set at a desired speed
and then the brakes are applied or
*is
pressed, the cruise control is disengaged
without erasing the set speed from memory.
Once the vehicle speed reaches about
40 km/h (25 mph) or more, briefly press
+RES. The vehicle returns to the previous set
speed.
Increasing Speed While Using Cruise Control
If the cruise control system is already
activated:
.Press and hold +RES on the steering
wheel until the vehicle accelerates to the
desired speed, then release it.
.To increase the speed in small increments,
briefly press +RES. For each press, the
vehicle goes about 1 km/h (1 mph) faster.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
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Driving and Operating 223
ACC can reduce the need for you to
frequently brake and accelerate, especially
when used on expressways, freeways, and
interstate highways. When used on other
roads, you may need to take over the
control of braking or acceleration more
often.
{Warning
ACC has limited braking ability and may
not have time to slow the vehicle down
enough to avoid a collision with another
vehicle you are following. This can occur
when vehicles suddenly slow or stop
ahead, or enter your lane. Also see
“Alerting the Driver”later in this section.
Complete attention is always required
while driving and you should be ready to
take action and apply the brakes. See
Defensive Driving 0187.
{Warning
ACC will not detect or brake for children,
pedestrians, animals, or other objects.
Do not use ACC when:
.On winding and hilly roads or when
the camera sensor is blocked by snow,
ice, or dirt. The system may not
detect a vehicle ahead. Keep the
windshield and headlamps clean.
.When visibility is poor due to rain,
snow, fog, dirt, insect residue, or dust;
when other foreign objects obscure
the camera’s view; or when the
vehicle in front or oncoming traffic
causes additional environmental
obstructions, such as road spray. ACC
performance is limited under these
conditions.
.On slippery roads where fast changes
in tire traction can cause excessive
wheel slip
.With extremely heavy cargo loaded in
the cargo area or rear seat
.When towing a trailer
J:Press to turn the system on or off. The
indicator turns white on the instrument
cluster when ACC is turned on.
RES+ : Press briefly to resume the previous
set speed or to increase vehicle speed if ACC
is already activated. To increase speed by
about 1 km/h (1 mph), press RES+ briefly. To
increase speed to the next 5 km/h (5 mph)
mark on the speedometer, hold RES+.
SET– :Press briefly to set the speed and
activate ACC or to decrease vehicle speed if
ACC is already activated. To decrease speed
by about 1 km/h (1 mph), press SET– briefly.
To decrease speed to the next 5 km/h
(5 mph) mark on the speedometer,
hold SET–.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
224 Driving and Operating
*:Press to disengage ACC without erasing
the selected set speed.
[: Press to select a following gap setting
for ACC of Far, Medium, or Near.
The speedometer reading can be displayed
in either English or metric units.
See Instrument Cluster (Base and Midlevel)
0 85 or
Instrument Cluster (Uplevel) 088. The
increment value used depends on the units
displayed.
Switching Between ACC and Regular Cruise
Control
To switch between ACC and regular cruise
control, press and hold
*. A Driver
Information Display (DIC) message displays.
See Vehicle Messages 0108.
ACC IndicatorRegular Cruise Control
Indicator When ACC is engaged, a green
oindicator
will be lit on the instrument cluster and the
following gap will be displayed. When the
regular cruise control is engaged, a green
Jindicator will be lit on the instrument
cluster; the following gap will not display.
When the vehicle is turned on, the cruise
control mode will be set to the last mode
used before the vehicle was turned off.
{Warning
Always check the cruise control indicator
on the instrument cluster to determine
which mode cruise control is in before
using the feature. If ACC is not active, the
vehicle will not automatically brake for
other vehicles, which could cause a crash
if the brakes are not applied manually.
You and others could be seriously injured
or killed.
Setting Adaptive Cruise Control
If
Jis on when not in use, SET–/RES+
could be pressed by mistake and engage
ACC when not desired. Keep
Joff when
cruise is not being used. Select the set speed desired for ACC. This is
the vehicle speed when no vehicle is
detected in your path.
While the vehicle is moving, ACC will not set
at a speed less than 5 km/h (3 mph),
although the minimum allowable set speed
is 25 km/h (15 mph).
To set ACC while moving:
1. Press
J.
2. Get up to the desired speed.
3. Press and release SET–.
4. Remove foot from the accelerator pedal.
After ACC is set, it may immediately apply
the brakes if a vehicle ahead is detected
closer than the selected following gap.
ACC can also be set while the vehicle is
stopped if ACC is on and the brake pedal is
applied.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
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Driving and Operating 225
The ACC indicator displays on the
instrument cluster. When ACC is turned on,
the indicator will be lit white. When ACC is
active, the indicator will turn green.
Be mindful of speed limits, surrounding
traffic speeds, and weather conditions when
selecting the set speed.
Resuming a Set Speed
If the ACC is set at a desired speed and then
the brakes are applied, ACC is disengaged
without erasing the set speed from memory.
To begin using ACC again, press RES+ up
briefly.
.If the vehicle is moving more than 5 km/h
(3 mph), it returns to the previous set
speed.
.If the vehicle is stopped with the brake
pedal applied, press RES+ and release the
brake pedal. ACC will hold the vehicle
until RES+ or the accelerator pedal is
pressed.
A green ACC indicator and the set speed
display on the instrument cluster. The
vehicle ahead indicator may be flashing if a
vehicle ahead was present and moved. See
“Approaching and Following a Vehicle” later
in this section. Once ACC has resumed, the vehicle speed
will increase to the set speed under the
following conditions:
.There is no vehicle ahead.
.The vehicle ahead is beyond the selected
following gap.
.The vehicle speed is not being limited
because of a sharp turn.
Increasing Speed While ACC Is at a Set Speed
If ACC is already activated, do one of the
following:
.Use the accelerator pedal to get to the
higher speed. Briefly press and release
SET– and release the accelerator pedal.
The vehicle will now cruise at the higher
speed.
When the accelerator pedal is pressed,
ACC will not brake because it is
overridden. While overridden, the ACC
indicator will turn blue on the instrument
cluster.
.Press and hold RES+ until the desired set
speed is displayed, then release it.
.To increase vehicle speed in smaller
increments, press RES+ briefly. For each
press, the vehicle goes about 1 km/h
(1 mph) faster.
.To increase vehicle speed in larger
increments, hold RES+. While holding RES
+, the vehicle speed increases to the next
5 km/h (5 mph) step, then continues to
increase by 5 km/h (5 mph) at a time.
The set speed can also be increased while
the vehicle is stopped.
.If stopped with the brake applied, press
RES+ until the desired set speed is
displayed.
.If ACC is holding the vehicle at a stop and
there is another vehicle directly ahead,
pressing RES+ will increase the set speed.
.Pressing RES+ when there is no longer a
vehicle ahead or the vehicle ahead is
pulling away and the brake is not applied
will cause ACC to resume.
When it is determined that there is no
vehicle ahead or the vehicle ahead is beyond
the selected following gap, then the vehicle
speed will increase to the set speed.
Reducing Speed While ACC Is at a Set Speed
If ACC is already activated, do one of the
following:
.Use the brake to get to the desired lower
speed. Release the brake and press SET–.
The vehicle will now cruise at the lower
speed.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
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Driving and Operating 227
following gap. The vehicle speed increases or
decreases to follow a detected vehicle in
front of your vehicle when that vehicle is
traveling slower than your vehicle set speed.
It may apply limited braking, if necessary.
When braking is active, the brake lamps 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 in front of your vehicle that have
a rear aspect that is low, small,
or irregular
.An empty truck or trailer that has no
cargo in the cargo bed
.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
.Vehicles that are low to the road surface
.Objects that are close to the front of your
vehicle
.Vehicles on which extremely heavy cargo
is loaded in the cargo area or rear seat
ACC Automatically Disengages
ACC may automatically disengage and the
driver will need to manually apply the
brakes to slow the vehicle if:
.The front camera is blocked or visibility is
reduced.
.The Traction Control System (TCS) or
StabiliTrak/ESC system has activated or
been disabled.
.There is a fault in the system.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
228 Driving and Operating
.A DIC message displays 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 0108.
When the vehicle ahead drives away, ACC
resumes automatically if the stop was brief.
If necessary, press RES+ or the accelerator
pedal to resume ACC. 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 0212. To 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 0108.
{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.
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, to indicate that
automatic braking will not occur. 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.
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.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
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Driving and Operating 229
{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 or 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.
Driving in Narrow Lanes
Vehicles in adjacent traffic lanes or roadside
objects may be incorrectly detected when
located along the roadway.