Cruise control GMC SIERRA 2020 User Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
198 Driving and Operating
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 0235.
. 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) 0232.
. 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.
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 0467. 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.
(Continued)
Warning (Continued)
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.
. Adjust the climate control
system to circulate the air
inside the vehicle and set
the fan speed to the highest
setting. See “Climate
Control Systems.”
For more information about CO,
see Engine Exhaust 0220.
To save fuel, run the engine for
short periods to warm the vehicle
and then shut the engine off and
partially close the window. Moving
about to keep warm also helps.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
226 Driving and Operating
10-Speed Automatic TransmissionGear before shifting from D (Drive) to
L (Manual Mode) 10th 9th 8th 7th 6th 5th 4th 3rd 2nd 1st
Range after shifting from D (Drive) to
L (Manual Mode) - Tow/Haul not engaged L7 L7 L7 L6 L5 L4 L3 L3 L2 L1
Range after shifting from D (Drive) to
L (Manual Mode) - Tow/Haul engaged L7 L7 L6 L5 L4 L3 L3 L3 L2 L1
Grade Braking is not available when
Range Selection Mode is active.
See Tow/Haul Mode 0226.
While using Range Selection Mode,
cruise control and the Tow/Haul
Mode can be used.
If the vehicle has an exhaust brake,
it can also be used, but will not
automatically downshift the
transmission. See “Exhaust Brake”
in the Duramax diesel supplement.
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.
Low Traction Mode
If equipped, Low Traction Mode
assists in vehicle acceleration when
road conditions are slippery, such as with ice or snow. While the
vehicle is at a stop, select L2 using
Range Selection Mode. This will
limit torque to the wheels and help
prevent the tires from spinning.
Tow/Haul Mode
The Tow/Haul Mode adjusts the
transmission shift pattern to reduce
shift cycling. This provides
increased performance, vehicle
control, and enhanced transmission
and engine cooling when driving
down steep hills or mountain
grades, when towing, or when
hauling heavy loads. See
Driver
Mode Control 0238 to activate Tow/
Haul Mode.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
236 Driving and Operating
intended path. Trailer Sway Control
(TSC) is also on automatically when
the vehicle is started. SeeTrailer
Sway Control (TSC) 0308.
If cruise control is being used and
traction control or StabiliTrak/ESC
begins to limit wheel spin, cruise
control will disengage. Cruise
control may be turned back on when
road conditions allow.
Both systems come on
automatically when the vehicle is
started and begins to move. The
systems may be heard or felt while
they are operating or while
performing diagnostic checks. This
is normal and does not mean there
is a problem with the vehicle.
It is recommended to leave both
systems on for normal driving
conditions, but it may be necessary
to turn TCS off if the vehicle gets
stuck in sand, mud, ice, or snow.
See If the Vehicle Is Stuck 0199
and “Turning the Systems Off and
On” later in this section. When the transfer case (if equipped)
is in Four-Wheel Drive Low, the
stability system is automatically
disabled,
gcomes on, and the
appropriate message will appear on
the Driver Information Center (DIC).
Both traction control and StabiliTrak/
ESC are automatically disabled in
this condition.
The indicator light for both systems
is in the instrument cluster. This
light will:
. Flash when TCS is limiting
wheel spin.
. Flash when StabiliTrak/ESC is
activated.
. Turn on and stay on when either
system is not working.
If either system fails to turn on or to
activate, a message displays in the
Driver Information Center (DIC), and
dcomes on and stays on to
indicate that the system is inactive
and is not assisting the driver in
maintaining control. The vehicle is
safe to drive, but driving should be
adjusted accordingly.
If
dcomes on and stays on:
1. Stop the vehicle.
2. Turn the engine off and wait 15 seconds.
3. Start the engine.
Drive the vehicle. If
dcomes on
and stays on, the vehicle may need
more time to diagnose the problem.
If the condition persists, see your
dealer.
Turning the Systems Off
and On

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 243
Locking Rear Axle
Vehicles with a locking rear axle can
give more traction on snow, mud,
ice, sand, or gravel. It works like a
standard axle most of the time, but
when traction is low, this feature will
allow the rear wheel with the most
traction to move the vehicle.
Cruise Control
{Warning
Cruise control can be dangerous
where you cannot drive safely at
a steady speed. Do not use
cruise control on winding roads or
in heavy traffic.
Cruise control can be dangerous
on slippery roads. On such roads,
fast changes in tire traction can
cause excessive wheel slip, and
you could lose control. Do not use
cruise control on slippery roads.
If equipped with cruise control, a
speed of about 40 km/h (25 mph) or
more can be maintained without
keeping your foot on the
accelerator. Cruise control does not
work at speeds below about
40 km/h (25 mph).
If the cruise control is being used
and the Traction Control System
(TCS) or StabiliTrak/Electronic
Stability Control (ESC) begins to
limit wheel spin, the cruise control will automatically disengage. See
Traction Control/Electronic Stability
Control
0235. If a collision alert
occurs when cruise control is
activated, cruise control is
disengaged. See Forward Collision
Alert (FCA) System 0268. When
road conditions allow you to safely
use it again, cruise control can be
turned back on.
Turning off the TCS or StabiliTrak/
ESC system will disengage the
cruise control.
If the brakes are applied, cruise
control disengages.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
244 Driving and Operating
5:Press to turn cruise control on
or off. A white indicator comes on or
off in the instrument cluster.
+RES : If there is a set speed in
memory, press the control up briefly
to resume to that speed or press
and hold to accelerate. If cruise
control is already engaged, use to
increase vehicle speed.
SET− :Press the control down
briefly to set the speed and activate
cruise control. If cruise control is
already engaged, use to decrease
vehicle speed.
*: Press to disengage cruise
control without erasing the set
speed from memory.
Setting Cruise Control
If
5is on when not in use, SET− or
+RES could get pressed and go into
cruise when not desired. Keep
5
off when cruise is not being used.
1. Press
5to turn the cruise
system on.
2. Get up to the desired speed. 3. Press and release SET−.
4. Remove your foot from the
accelerator.
The cruise control indicator on the
instrument cluster turns green after
cruise control has been set to the
desired speed. See Instrument
Cluster 0127.
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 reaches about
40 km/h (25 mph) or more, press
RES+ up briefly. The vehicle returns
to the previously set speed.
Increasing Speed While Using
Cruise Control
Do one of the following:
. Press and hold +RES up until
the desired speed is reached,
then release it. .
To increase vehicle speed in
small increments, press +RES
up briefly. For each press, the
vehicle goes about 1 km/h
(1 mph) faster.
The speedometer reading can be
displayed in either English or metric
units. See Instrument Cluster 0127.
The increment value used depends
on the units displayed.
Reducing Speed While Using
Cruise Control
Do one of the following:
. Press and hold SET– down until
the desired lower speed is
reached, then release it.
. To slow down in small
increments, press SET– down
briefly. For each press, the
vehicle goes about 1 km/h
(1 mph) slower.
The speedometer reading can be
displayed in either English or metric
units. See Instrument Cluster 0127.
The increment value used depends
on the units displayed.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 245
Passing Another Vehicle While
Using Cruise Control
Use the accelerator pedal to
increase the vehicle speed. When
you take your foot off the pedal, the
vehicle will slow down to the
previously set cruise speed. While
pressing the accelerator pedal or
shortly following the release to
override cruise control, briefly
pressing SET–will result in cruise
control set to the current vehicle
speed.
Using Cruise Control on Hills
How well the cruise control works
on hills depends on the vehicle
speed, the load, and the steepness
of the hills. When going up steep
hills, pressing the accelerator pedal
may be necessary to maintain
vehicle speed.
While going downhill, cruise braking
helps maintain driver selected
speed.
Cruise Grade Braking is enabled
when the vehicle is started and
cruise control is active. It is not
enabled in Range Selection Mode. It assists in maintaining driver
selected speed when driving on
downhill grades by using the engine
and transmission to slow the
vehicle.
For other forms of descent control,
see
Hill Descent Control (HDC)
0 237, Automatic Transmission
0 221, and Tow/Haul Mode 0226.
Ending Cruise Control
There are four ways to end cruise
control:
. Step lightly on the brake pedal.
. Press
*.
. Shift the transmission to
N (Neutral).
. To turn off cruise control,
press
5.
Erasing Speed Memory
The cruise control set speed is
erased from memory if
5is pressed
or the ignition is turned off.
Adaptive Cruise Control
(1500 Series)
If equipped, Adaptive Cruise Control
(ACC) allows the cruise control set
speed and following gap to be
selected. Read this entire section
before using this system. The
following gap is the following time
between your vehicle and a vehicle
detected directly ahead in your path,
moving in the same direction. If no
vehicle is detected in your path,
ACC works like regular cruise
control. ACC uses a windshield
mounted front camera sensor.
If a vehicle is detected in your path,
ACC can apply acceleration or
limited, moderate braking to
maintain the selected following gap.
To disengage ACC, apply the brake.
If ACC is controlling the vehicle
speed when the Traction Control
System (TCS) or StabiliTrak/
Electronic Stability Control (ESC)
system activates, ACC may
automatically disengage. See
Traction Control/Electronic Stability
Control 0235. When road
conditions allow ACC to be safely

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 247
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–.
*: 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 0127.
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 0156.
ACC IndicatorRegular Cruise
Control Indicator
When ACC is engaged, a green
o
indicator will be lit on the instrument
cluster and the following gap will be
displayed. When the regular cruise
control is engaged, a green
J
indicator 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
248 Driving and Operating
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 25
km/h (15 mph), although it can be
resumed when driving at lower
speeds.
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.
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.
The ACC indicator displays on the
instrument cluster. When ACC is
turned on, the indicator will be lit
white.
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+ briefly while moving more
than 5 km/h (3 mph). The vehicle
returns to the previous set speed.
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, if there is
no vehicle ahead, if the vehicle
ahead is beyond the selected
following gap, or if the vehicle has
exited a sharp curve, then the
vehicle speed will increase to the
set speed.
Increasing Speed While ACC Is at
a Set Speed
If ACC is already activated, do one
of the following:
. Use the accelerator to get to the
higher speed. Press SET–.
Release SET– and the
accelerator pedal. The vehicle
will now cruise at the higher
speed.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
252 Driving and Operating
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”previously
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” under
Vehicle Personalization 0157. When the vehicle ahead drives
away, 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 0233.
A DIC warning message may
display indicating to shift to P (Park)
before exiting the vehicle. See
Vehicle Messages 0156.
{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
indicating ACC 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 255
Lighting Conditions Affecting ACC
The ACC front camera can be
affected by poor lighting conditions,
and ACC may have limited
performance when:
.There are changes in brightness,
such as entering and exiting
tunnels, bridges, and
overpasses.
. Low sun angles cause the
camera to not detect objects,
or it is more difficult to detect
objects in the same traffic lane.
. Lighting is poor in the evening or
early morning
. There are multiple changes in
brightness or shadows along the
vehicle roadway.
. In a tunnel without the
headlamps on, or in a tunnel
when there is a vehicle in front
that does not have its
taillamps on. .
Subjected to strong light from
opposing lane traffic in the front
of the vehicle, such as
high-beam headlamps from
oncoming traffic.
Accessory Installations and
Vehicle Modifications
Do not install or place any object
around the front camera windshield
area that would obstruct the front
camera view.
Do not install objects on top of the
vehicle that overhang and obstruct
the front camera, such as a canoe,
kayak, or other items that can be
transported on the vehicle roof.
Do not modify the hood, headlamps,
or fog lamps, as this may limit the
camera’s ability to detect an object.
Cleaning the Sensing System
The camera sensor on the
windshield behind the rearview
mirror can become blocked by
snow, ice, dirt, mud, or debris. This
area needs to be cleaned for ACC
to operate properly. The vehicle headlamps may need to
be cleaned due to dirt, snow, or ice.
Objects that are not illuminated
correctly may be difficult to detect.
If ACC will not operate, regular
cruise control may be available. See
“Switching Between ACC and
Regular Cruise Control”
previously
in this section. Always consider
driving conditions before using
either cruise control system.
For cleaning instructions, see
“Washing the Vehicle” under
Exterior Care 0429.