2015 GMC SIERRA cruise control

Black plate (38,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-38 Driving and Operating
6–Speed Automatic TransmissionGear before shifting from D
(Drive) to M (Manual Mode) 6th 5th 4th 3rd 2nd 1st
Range after shifting from D
(Drive) to M (Manual Mode) M4 M4 M3 M2 M2 M1
8–Speed Automatic Transmission Gear before
shifting from D
(Drive) to M
(Manual Mode) 8th 7th 6th 5th 4th 3rd 2nd 1st
Range after
shifting from
D (Drive) to
M (Manual Mode)
– Tow/Haul not
engaged M6 M6 M5 M4 M3 M3 M2 M1
Range after
shifting from
D (Drive) to
M (Manual Mode)
– Tow/Haul
engaged M6 M5 M4 M3 M3 M3 M2 M1 Grade Braking is not available when
Range Selection Mode is active.
See
Tow/Haul Mode on page 9-39.
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 you are
stuck, do not spin the tires. When
stopping on a hill, use the brakes
to hold the vehicle in place.

Black plate (39,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-39
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 M2 using
Range Selection Mode. This will
limit torque to the wheels and help
to prevent the tires from spinning.
Tow/Haul Mode
The vehicle has a Tow/Haul Mode.
The Tow/Haul Mode adjusts the
transmission shift pattern to reduceshift cycling, providing increased
performance, vehicle control, and
enhanced transmission and engine
cooling when driving down steep
hills or mountain grades, towing,
or hauling heavy loads.
The selector button is on the end of
the shift lever. Turn the Tow/Haul
Mode on and off by pressing the
button. When the Tow/Haul Mode is
enabled, a light on the instrument
cluster will come on.
See
Tow/Haul Mode Light on
page 5-22 andHill and Mountain
Roads on page 9-11.
Also see “Tow/Haul Mode” under
Towing Equipment on page 9-78.
Tow/Haul Mode Grade Braking
Tow/Haul Mode Grade Braking is
only enabled while the Tow/Haul
Mode is selected and the vehicle is
not in the Range Selection Mode.
See “Tow/Haul Mode” listed
previously and Manual Mode on
page 9-36. Tow/Haul Mode Grade
Braking assists in maintaining desired vehicle speeds when driving
on downhill grades by using the
engine and transmission to slow the
vehicle.
On vehicles with a gasoline engine,
to disable or enable Tow/Haul
Grade Braking within the current
ignition key cycle, press and hold
the Tow/Haul button for
five seconds. When the button is
released, the requested mode
change is made. A DIC message is
displayed. See
Transmission
Messages on page 5-39.
On vehicles with a diesel engine,
Tow/Haul Mode Grade Braking can
be enabled or disabled by pressing
the Tow/Haul Mode button. Use the
exhaust brake and Tow/Haul Mode
for maximum grade braking.
See Towing Equipment on
page 9-78.
For other forms of grade braking,
see Automatic Transmission on
page 9-33 andCruise Control on
page 9-52.

Black plate (49,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-49
hills (less than 5% grade) with a
loaded vehicle or while pulling a
trailer where HSA may activate.
If you release the brake pedal and
then reapply the brake pedal while
HSA is activated, the brake pedal
typically feels firmer with less pedal
travel.Ride Control Systems
Traction Control/
Electronic Stability
Control
System Operation
The vehicle has a Traction Control
System (TCS) and StabiliTrak®, an
electronic stability control system.
These systems help limit wheel spin
and assist the driver in maintaining
control, especially on slippery road
conditions.
TCS activates if it senses any of the
drive wheels are spinning or
beginning to lose traction. When this
happens, TCS applies the brakes to
the spinning wheels and reduces
engine power to limit wheel spin.
StabiliTrak activates when the
vehicle senses a difference between
the intended path and the direction
the vehicle is actually traveling.
StabiliTrak selectively applies
braking pressure to any one of the vehicle wheel brakes to assist the
driver in keeping the vehicle on the
intended path. Trailer Sway Control
(TSC) is also on automatically when
the vehicle is started. See
Trailer
Sway Control (TSC) on page 9-87.
If cruise control is being used and
traction control or StabiliTrak 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.

Black plate (52,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-52 Driving and Operating
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.
5must be pressed
again to re-enable HDC.
When enabled, if the vehicle is at a
speed above 22 km/h (14 mph) and
less than 60 km/h (37 mph), a DIC
message will display. See Vehicle
Speed Messages on page 5-42.
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
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).
{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 an Allison or
Hydra-Matic 6-speed automatic
transmission, see
“Tow/Haul Mode
Grade Braking” underTow/Haul
Mode on page 9-39 for an
explanation of how cruise control
interacts with the Range Selection
Mode, Tow/Haul Mode, and Grade
Braking systems.
If the cruise control is being used
and the Traction Control System
(TCS) or StabiliTrak begins to limit
wheel spin, the cruise control will
automatically disengage. See
Traction Control/Electronic Stability
Control on page 9-49. If a collision
alert occurs when cruise control is
activated, cruise control is
disengaged. See Forward Collision
Alert (FCA) System on page 9-59.
When road conditions allow you to
safely use it again, cruise control
can be turned back on.
If the brakes are applied, the cruise
control disengages.

Black plate (53,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-53
5(On/Off):Press to turn the
system on or off. A white indicator
comes on in the instrument cluster
when cruise control is on and turns
off when cruise control is off.
+RES (Resume/Accelerate): If
there is a set speed in memory,
press briefly to resume to that
speed or press and hold to
accelerate. If cruise control is
already active, use to increase
vehicle speed. SET−
(Set/Coast): Press briefly to
set the speed and activate cruise
control. If cruise control is already
active, use to decrease vehicle
speed.
*(Cancel): 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 foot from the accelerator.
The cruise control indicator on the
instrument cluster turns green after
cruise control has been set to the
desired speed. SeeInstrument
Cluster on page 5-9. 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,
press the +RES button briefly. 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 the +RES button
until the desired speed is
reached, then release it.
.To increase vehicle speed in
small increments, briefly press
the +RES button. For each
press, the vehicle goes about
1.6 km/h (1 mph) faster.

Black plate (54,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-54 Driving and Operating
The speedometer reading can be
displayed in either English or metric
units. SeeInstrument Cluster on
page 5-9. The increment value used
depends on the units displayed.
Reducing Speed While Using
Cruise Control
If the cruise control system is
already activated:
.Press and hold the SET– button
until the desired lower speed is
reached, then release it.
.To slow down in small
increments, briefly press the
SET– button. For each press,
the vehicle goes about 1.6 km/h
(1 mph) slower.
The speedometer reading can be
displayed in either English or metric
units. See Instrument Cluster on
page 5-9. The increment value used
depends on the units displayed. 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
previous set cruise speed. While
pressing the accelerator pedal or
shortly following the release to
override cruise control, briefly
pressing the SET–
button 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:
.Vehicles with a 6-speed
automatic transmission and a
gasoline engine have Cruise
Grade Braking to help 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.
To disable and enable Cruise
Grade Braking for the current
ignition key cycle, press and
hold the Tow/Haul button for
five seconds. A DIC message
displays. See
Transmission
Messages on page 5-39.
.Vehicles with a diesel engine
have Cruise Grade Braking
enabled when Tow/Haul Mode is
on, the exhaust brake is on,
or both are on.

Black plate (55,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-55
For other forms of Grade Braking,
seeAutomatic Transmission on
page 9-33 ,Tow/Haul Mode on
page 9-39, and Hill Descent Control
(HDC) on page 9-51.
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.
Driver Assistance
Systems
This vehicle may have features that
work together to help avoid crashes
or reduce crash damage while
driving, backing, and parking. Read
this entire section before using
these systems.
{Warning
Do not rely on the Driver
Assistance Systems. These
systems do not replace the need
for paying attention and driving
safely. You may not hear or feel
alerts or warnings provided by
these systems. Failure to use
proper care when driving may
result in injury, death, or vehicle
damage. See Defensive Driving
on page 9-3.
(Continued)
Warning (Continued)
Under many conditions, these
systems will not:
.Detect children, pedestrians,
bicyclists, or animals.
.Detect vehicles or objects
outside the area monitored by
the system.
.Work at all driving speeds.
.Warn you or provide you with
enough time to avoid a crash.
.Work under poor visibility or
bad weather conditions.
.Work if the detection sensor
is not cleaned or is covered
by ice, snow, mud, or dirt.
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.

Black plate (60,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-60 Driving and Operating
Warning (Continued)
or ice, or if the windshield is
damaged. It may also not detect a
vehicle on winding or hilly roads,
or in conditions that can limit
visibility such as fog, rain,
or snow, or if the headlamps or
windshield are not cleaned or in
proper condition. Keep the
windshield, headlamps, and FCA
sensors clean and in good repair.Collision Alert
When your vehicle approaches
another detected vehicle too rapidly,
the red FCA display will flash on the
windshield. Also, eight rapid
high-pitched beeps will sound from
the front, or both sides of the Safety
Alert Seat will pulse five times.
When this Collision Alert occurs, the
brake system may prepare for driver
braking to occur more rapidly which
can cause a brief, mild deceleration.
Continue to apply the brake pedal as needed. Cruise control may be
disengaged when the Collision Alert
occurs.
Tailgating Alert
The vehicle ahead indicator will
display amber when you are
following a vehicle ahead much too
closely.