2020 GMC SIERRA stop start

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 235
pedal pulsation, and/or pedal
movement during this time may
occur. Continue to apply the brake
pedal as the driving situation
dictates. Brake Assist disengages
when the brake pedal is released.
Hill Start Assist (HSA)
{Warning
Do not rely on the HSA feature.
HSA does not replace the need to
pay attention and drive safely.
You may not hear or feel alerts or
warnings provided by this system.
Failure to use proper care when
driving may result in injury, death,
or vehicle damage. See
Defensive Driving0187.
When the vehicle is stopped on a
grade, Hill Start Assist (HSA)
prevents the vehicle from rolling in
an unintended direction during the
transition from brake pedal release
to accelerator pedal apply. The
brakes release when the accelerator
pedal is applied. If the accelerator pedal is not applied within a few
minutes, the Electric Parking Brake
will apply. The brakes may also
release under other conditions. Do
not rely on HSA to hold the vehicle.
HSA is available when the vehicle is
facing uphill in a forward gear,
or when facing downhill in
R (Reverse). The vehicle must
come to a complete stop on a grade
for HSA to activate.
Ride Control Systems
Traction Control/
Electronic Stability
Control
System Operation
The vehicle has a Traction Control
System (TCS) and StabiliTrak/
Electronic Stability Control (ESC)
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/ESC activates when the
vehicle senses a difference between
the intended path and the direction
the vehicle is actually traveling.
StabiliTrak/ESC selectively applies
braking pressure to any one of the
vehicle wheel brakes to assist the
driver in keeping the vehicle on the

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 237
The button for TCS and StabiliTrak/
ESC is on the center stack.
Caution
Do not repeatedly brake or
accelerate heavily when TCS is
off. The vehicle driveline could be
damaged.
To turn off only TCS, press and
release
g. The traction off lighti
displays in the instrument cluster.
The appropriate message will
display in the DIC. To turn TCS on
again, press and release
g. The
traction off light
idisplayed in the
instrument cluster will turn off.
If TCS is limiting wheel spin when
g
is pressed, the system will not turn
off until the wheels stop spinning.
To turn off both TCS and StabiliTrak/
ESC, press and hold
guntil the
traction off light
iand the
StabiliTrak/ESC OFF light
gcome
on and stay on in the instrument cluster, then release. The
appropriate message will display in
the DIC.
To turn TCS and StabiliTrak/ESC on
again, press and release
g. The
traction off light
iand the
StabiliTrak/ESC OFF light
gin the
instrument cluster turn off.
StabiliTrak/ESC will automatically
turn on if the vehicle exceeds
56 km/h (35 mph). Traction control
will remain off.
The vehicle has a Trailer Sway
Control (TSC) feature and a Hill
Start Assist (HSA) feature. See
Trailer Sway Control (TSC) 0308 or
Hill Start Assist (HSA) 0235.
Adding accessories can affect the
vehicle performance. See
Accessories and Modifications
0 329.
Hill Descent
Control (HDC)
If equipped, Hill Descent Control
(HDC) sets and maintains vehicle
speed while driving down steep
grades in a forward or reverse gear.
The HDC switch is on the center
stack, below the climate controls.
Press
5to enable or disable HDC.
Vehicle speed must be below
50 km/h (31 mph).
When enabled, the HDC light
displays on the instrument cluster.
A blinking HDC light indicates the
system is actively applying the
brakes to maintain vehicle speed.
HDC can maintain vehicle speeds
between 1 and 22 km/h (1 and
14 mph) on grades greater than or
equal to 10%.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
240 Driving and Operating
Off-Road Mode
Use to improve driving at moderate
speeds, on grass, gravel, dirt,
unpaved roads, or snow-covered
roads that have not been groomed
or plowed.
The accelerator pedal will be more
sensitive to provide finer control of
the torque at the wheels.
StabiliTrak/Electronic Stability
Control (ESC), the Antilock Brake
System (ABS), and the Traction
Control System (TCS) will change
for optimal off-road performance.
Use this mode for public off-road
recreational driving. SeeOff-Road
Driving 0191.
When selected, the Off-Road Mode
indicator light displays in the
instrument cluster. Tow/Haul Mode
This feature assists when pulling a
heavy trailer or a heavy load. See
Tow/Haul Mode
0226.
Tow/Haul Mode is designed to be
most effective when the vehicle and
trailer combined weight is at least
75% of the vehicle’s Gross
Combined Weight Rating (GCWR).
See “Weight of the Trailer” under
Trailer Towing 0292.
Tow/Haul Mode is most useful when
pulling a heavy trailer or a heavy
load under the following conditions:
. Through rolling terrain
. In stop-and-go traffic
. In busy parking lots where
improved low speed control of
the vehicle is desired
Operating the vehicle in Tow/Haul
Mode when lightly loaded or with no
trailer at all will not cause damage.
However, there is no benefit to
selecting Tow/Haul Mode when the
vehicle is unloaded. Such a
selection when unloaded may result
in unpleasant engine and transmission driving characteristics,
heavy or light steering, and reduced
fuel economy.
When selected, the Tow/Haul Mode
light will display in the instrument
cluster.
If the vehicle is turned off with Tow/
Haul Mode active and then restarted
within four hours or less, Tow/Haul
will remain active. Otherwise the
vehicle will start in Normal Mode.
Terrain Mode
Use for finer control during low
speed, off-road driving. When using
this mode it will mimic the
characteristics of four-wheel-drive
low (4
n) without the torque
capabilities.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
242 Driving and Operating
Terrain ModeDrive Select Expected Vehicle Behavior Ideal Terrain
L1 Significant deceleration when
off throttle and significant
ability to modulate throttle;
will bring vehicle to a stop in
most cases.
Rock crawling downhill
Active Braking During Lift Throttle
will reduce the back and forth
between the accelerator and brake
pedals.
Vehicle Hold Features:
. When the vehicle comes to a
stop on an incline grade in
forward gear or on a decline
grade in reverse gear, Vehicle
Hold is engaged until the
accelerator pedal is pressed.
. When the vehicle is in forward
gear on a decline, the vehicle is
allowed to creep down the hill
when the brake pedal is
released without pressing the accelerator pedal. The vehicle
will also creep forward on flat
ground.
. If the driver seat belt is removed
and the driver door is opened
while the vehicle is being held,
EPB will be engaged.
. EPB will engage if the vehicle is
held for an extended period.
Terrain Mode is only available on
vehicles equipped with the single
speed transfer case.
Terrain Mode can only be
active when:
. Vehicle speed is less than
80 km/h (50 mph).
. The transfer case is in 4
m. Frequent use of this mode may
cause brake wear due to the light
braking.
The vehicle will automatically exit
the mode if the brakes get too hot.
Terrain Mode can be turned back on
after the brakes have cooled.
When Terrain Mode is selected:
.
Auto Engine Start/Stop will be
disabled.
. The Terrain Mode indicator
displays on the instrument
cluster.
Limited-Slip Differential
If equipped, the limited-slip
differential 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 allows the drive wheel
with the most traction to move the
vehicle. For vehicles with the
limited-slip differential, driven under
severe conditions, the rear axle fluid
should be changed. See
Maintenance Schedule 0442.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 285
Filling the Tank (Chassis
Cab Model)
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
An arrow on the fuel gauge
indicates which side of the vehicle
the fuel door is on. SeeFuel Gauge
0 132.
{Warning
Fuel vapors and fuel fires burn
violently and can cause injury or
death.
Follow these guidelines to help
avoid injuries to you and others:
. Read and follow all the
instructions on the fuel
pump island.
. Turn off the engine when
refueling.
. Keep sparks, flames, and
smoking materials away
from fuel.
(Continued)
Warning (Continued)
.Do not leave the fuel pump
unattended.
. Avoid using electronic
devices while refueling.
. Do not re-enter the vehicle
while pumping fuel.
. Keep children away from
the fuel pump and never let
children pump fuel.
. Before touching the fill
nozzle, touch a metallic
object to discharge static
electricity from your body.
. Fuel can spray out if the fuel
cap is opened too quickly.
This spray can happen if the
tank is nearly full, and is
more likely in hot weather.
Open the fuel cap slowly
and wait for any hiss noise
to stop, then unscrew the
cap all the way. Turn the fuel cap counterclockwise
to remove. Fully insert and latch the
fill nozzle, begin fueling. If the
vehicle is a dual fuel tank chassis
cab model, and it runs out of fuel,
refuel the front fuel tank first to
ensure a quick restart.
{Warning
Overfilling the fuel tank by more
than three clicks of a standard fill
nozzle may cause:
. Vehicle performance issues,
including engine stalling and
damage to the fuel system.
. Fuel spills.
. Under certain conditions,
fuel fires.
Be careful not to spill fuel. Wait
five seconds after you have finished
pumping before removing the fill
nozzle. Clean fuel from painted
surfaces as soon as possible. See
Exterior Care 0429. Reinstall the
cap by turning it clockwise until it
clicks.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 287
Trailer Towing
General Towing
Information
Only use towing equipment that has
been designed for the vehicle.
Contact your dealer or trailering
dealer for assistance with preparing
the vehicle to tow a trailer. Read the
entire section before towing a trailer.
To tow a disabled vehicle, see
Towing the Vehicle0424. To tow
the vehicle behind another vehicle
such as a motor home, see
Recreational Vehicle Towing 0424.
Driving Characteristics
and Towing Tips
{Warning
You can lose control when towing
a trailer if the correct equipment is
not used or the vehicle is not
driven properly. For example,
if the trailer is too heavy or the
(Continued)
Warning (Continued)
trailer brakes are inadequate for
the load, the vehicle may not stop
as expected. You and others
could be seriously injured. The
vehicle may also be damaged,
and the repairs would not be
covered by the vehicle warranty.
Pull a trailer only if all the steps in
this section have been followed.
Ask your dealer for advice and
information about towing a trailer
with the vehicle.
Driving with a Trailer
Trailering is different than just
driving the vehicle by itself.
Trailering means changes in
handling, acceleration, braking,
durability, and fuel economy.
Successful, safe trailering takes
correct equipment, and it has to be
used properly.
The following information has many
time-tested, important trailering tips
and safety rules. Many of these are important for your safety and that of
your passengers. Read this section
carefully before pulling a trailer.
When towing a trailer:
.
Become familiar with and follow
all state and local laws that
apply to trailer towing. These
requirements vary from state to
state.
. State laws may require the use
of extended side view mirrors.
Even if not required, you should
install extended side view
mirrors if your visibility is limited
or restricted while towing.
. Do not tow a trailer during the
first 800 km (500 mi) of vehicle
use to prevent damage to the
engine, axle, or other parts.
. It is recommended to perform
the first oil change before heavy
towing.
. During the first 800 km (500 mi)
of trailer towing, do not drive
over 80 km/h (50 mph) and do
not make starts at full throttle.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
290 Driving and Operating
The vehicle can tow in D (Drive).
Shift the transmission to a lower
gear if the transmission shifts too
often under heavy loads and/or hilly
conditions.
When towing at higher altitudes,
engine coolant will boil at a lower
temperature than at lower altitudes.
If the engine is turned off
immediately after towing at high
altitude on steep uphill grades, the
vehicle could show signs similar to
engine overheating. To avoid this,
let the engine run, preferably on
level ground, with the transmission
in P (Park) for a few minutes before
turning the engine off. If the
overheat warning comes on, see
Engine Overheating0351.
Viewing Systems
If equipped, the viewing systems on
the vehicle can improve visibility
while hitching, backing, and driving
with a trailer. See Driver Assistance
Systems 0256.
Parking on Hills
{Warning
To prevent serious injury or death,
always park your vehicle and
trailer on a level surface when
possible.
When parking your vehicle and your
trailer on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn
the wheels into the curb if
facing downhill or into traffic if
facing uphill.
2. Have someone place chocks under the trailer wheels.
3. Gradually release the brake pedal to allow the chocks to
absorb the load of the trailer.
4. Reapply the brake pedal. Then apply the parking brake and
shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
.Start the engine.
. Shift into a gear.
. Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Launching and Retrieving
a Boat
Backing the Trailer into the Water
{Warning
.Have all passengers get out
of the vehicle before
backing onto the sloped part
of the ramp. Lower the
driver and passenger side
windows before backing
onto the ramp. This will
(Continued)