2020 GMC SIERRA change time

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
186 Driving and Operating
Lane Change Alert (LCA) . . . . . 274
Lane Departure Warning(LDW) (2500/3500
Series) . . . . . . . . . . . . . . . . . . . . . . 276
Lane Keep Assist (LKA) (1500
Series) . . . . . . . . . . . . . . . . . . . . . . 278
Fuel
Top Tier Fuel . . . . . . . . . . . . . . . . . 280
Recommended Fuel (Except6.2L V8 Engine) . . . . . . . . . . . . . 280
Recommended Fuel (6.2L V8 Engine) . . . . . . . . . . . . . . . . . . 281
Prohibited Fuels . . . . . . . . . . . . . . 281
Fuels in Foreign Countries . . . 281
Fuel Additives . . . . . . . . . . . . . . . . 282
E85 or FlexFuel . . . . . . . . . . . . . . 282
Filling the Tank (Pickup Model) . . . . . . . . . . . . . . . . . . . . . . 283
Filling the Tank (Chassis Cab Model) . . . . . . . . . . . . . . . . . . . . . . 285
Filling a Portable Fuel Container . . . . . . . . . . . . . . . . . . . 286
Trailer Towing
General TowingInformation . . . . . . . . . . . . . . . . . . 287
Driving Characteristics and Towing Tips . . . . . . . . . . . . . . . . . 287
Trailer Towing . . . . . . . . . . . . . . . . 292
Towing Equipment . . . . . . . . . . . . 296 Trailer Sway Control (TSC) . . . 308
Trailering App . . . . . . . . . . . . . . . . 310
Conversions and Add-Ons
Add-On Electrical
Equipment . . . . . . . . . . . . . . . . . . 322
Adding a Snow Plow or Similar Equipment . . . . . . . . . . . . . . . . . . 323
Pickup Conversion to Chassis Cab . . . . . . . . . . . . . . . . 326
Driving Information
Driving for Better Fuel
Economy
Driving habits can affect fuel
mileage. Here are some driving tips
to get the best fuel economy
possible:
. Set the climate controls to the
desired temperature after the
engine is started, or turn them
off when not required.
. Avoid fast starts and accelerate
smoothly.
. Brake gradually and avoid
abrupt stops.
. Avoid idling the engine for long
periods of time.
. When road and weather
conditions are appropriate, use
cruise control.
. Always follow posted speed
limits or drive more slowly when
conditions require.
. Keep vehicle tires properly
inflated.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 231
Shifting Into N (Neutral)
To shift into N (Neutral):1. Start the vehicle.
2. Shift the transmission to N (Neutral).
3. Shift the transfer case to 2
m.
4. Apply the parking brake and/or brake pedal.
5. Press 2
mfive times in
10 seconds until the N (Neutral)
graphic starts flashing in the
instrument cluster. When the
shift is complete, the graphic
stops flashing. If the parking
brake and/or brake pedal is not
applied within 20 seconds, the
transfer case will remain in the
original state.
6. If the transmission is not shifted into N (Neutral) or the
vehicle has not slowed to
5 km/h (3 mph) within
20 seconds, the transfer case
will remain in its original state.
This will be indicated in the
instrument cluster. Shifting Out of N (Neutral)
To shift out of N (Neutral):
1. Turn the ignition on with the engine off. See Ignition
Positions (Keyless Access)
0 208 or
Ignition Positions (Key Access)
0 210.
2. Set the parking brake. See Electric Parking Brake 0233.
3. Shift the transmission to N (Neutral).
4. Shift the transfer case to 2
m.
Transfer case shifts out of
N (Neutral) can only be made
into 2
m. When the shift to 2mis
complete, the graphic in the
instrument cluster will stop
flashing. If the transfer case
cannot complete a shift, the
graphic will return to the
previously selected setting. Single Speed Transfer Case
If equipped, the transfer case
controls are used to shift into and
out of four-wheel drive.
To shift the transfer case, press the
desired button. The graphic in the
instrument cluster will flash while a
shift is in progress. The graphic
displayed will change to indicate the
setting requested.
When the shift is complete the
graphic will stop flashing. The DIC
message turns off once the shift is
complete. If the transfer case

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
232 Driving and Operating
cannot complete a shift request, it
will go back to its last chosen
setting.
The settings are:
2
m(Two-Wheel Drive High) :Use
for driving on most streets and
highways. The front axle is not
engaged. This setting provides the
best fuel economy.
4
m(Four-Wheel Drive High) : Use
this setting when extra traction is
needed, such as when driving on
snowy or icy roads, when
off-roading, or when plowing snow.
AUTO (Automatic Four-Wheel
Drive)
Use when road surface conditions
are variable. When driving in AUTO,
the front axle is engaged, and the
vehicle's power is sent to the front
and rear wheels automatically
based on driving conditions. This
setting provides slightly lower fuel
economy than 2
m. Shifts between 2
m, 4m, and AUTO
Any of these shifts can be made at
normal driving speed.
The actual 4x4 shift request is only
made after the button is released.
The 4x4 graphic will remain flashing
until the shift request has
completed. A DIC message
displays.
Once the 4x4 shift has completed,
the DIC message disappears, the
4x4 graphic stops flashing, and the
current setting is indicated.
The actual 4x4 shift request is only
made after the button is released.
The 4x4 graphic will remain flashing
until the shift request has
completed.
A DIC message displays. Once the
4x4 shift has completed, the DIC
message disappears, the 4x4
graphic stops flashing, and the
current setting is indicated.Brakes
Electric Brake Boost
Vehicles equipped with electric
brake boost have hydraulic brake
circuits that are electronically
controlled when the brake pedal is
applied during normal operation.
The system performs routine tests
and turns off within a few minutes
after the vehicle is shutdown. Noise
may be heard during this time. If the
brake pedal is pressed during the
tests or when the electric brake
boost system is off, a noticeable
change in pedal force and travel
may be felt. This is normal.
Antilock Brake
System (ABS)
The Antilock Brake System (ABS)
helps prevent a braking skid and
maintain steering while
braking hard.
ABS performs a system check when
the vehicle is first driven.
A momentary motor or clicking noise

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 233
may be heard while this test is going
on, and the brake pedal may move
slightly. This is normal.
If there is a problem with ABS, this
warning light stays on. SeeAntilock
Brake System (ABS) Warning Light
0 141.
ABS does not change the time
needed to get a foot on the brake
pedal and does not always
decrease stopping distance. If you
get too close to the vehicle ahead,
there will not be enough time to
apply the brakes if that vehicle
suddenly slows or stops. Always
leave enough room ahead to stop,
even with ABS.
Using ABS
Do not pump the brakes. Just hold
the brake pedal down firmly.
Hearing or feeling ABS operate is
normal.
Braking in Emergencies
ABS allows steering and braking at
the same time. In many
emergencies, steering can help
even more than braking.
Electric Parking Brake
The vehicle has an Electric Parking
Brake (EPB). The EPB can always
be activated, even if the ignition is off. To prevent draining the battery,
avoid repeated cycles of the EPB
when the engine is not running.
The system has a
Yor PARK
Electric Parking Brake light, and a
8
Service Parking Brake light. See
Electric Parking Brake Light 0141
and
Service Electric Parking Brake Light
0 141. There are also parking
brake-related Driver Information
Center (DIC) messages.
Before leaving the vehicle, check for
the
Yor PARK light to ensure that
the parking brake is applied.
EPB Apply
To apply the EPB:
1. Be sure the vehicle is at a complete stop.
2. Press the EPB switch momentarily.
The
Yor PARK light will flash and
then stay on once the EPB is fully
applied. If the
Yor PARK light
flashes continuously, then the EPB

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
238 Driving and Operating
If HDC is to be used for more than
three minutes or on grades steeper
than 25%, the transfer case should
be put into Four-Wheel Drive Low (4
n) to reduce the possibility of brake
overheating.
Noise from the Electronic Brake
Control Module (EBCM) is normal
when HDC is active.
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
30 and 60 km/h (19 and 37 mph);
however, vehicle speed cannot be
set or maintained in this range. HDC
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. HDC may disable
after an extended period of use. If this happens, HDC will require
time to cool down. The length of
time HDC remains active depends
on road conditions, grade, set
speed, vehicle loading, and outside
temperature.
When enabled, if the vehicle speed
is above 30 km/h (19 mph) and
below 60 km/h (37 mph), a DIC
message will display.
Driver Mode Control
This feature adds a sportier feel,
provides a more comfortable ride,
or assists in different weather
conditions or terrain. Depending on
the option package, available
features, and mode selected; the
suspension, steering, and
powertrain will change settings to
achieve the desired mode
characteristics. If the vehicle is
equipped with magnetic ride control,
selecting the various Driver Modes
enhances the ride performance for
the road conditions and the
selected mode.
Mode availability is dependent upon
vehicle trim level, region, and
optional features.
Not all drive modes are available
on. 1500 series vehicles may have
Normal, Sport, Off Road, Terrain,
and Tow Haul. 2500/3500 series
vehicles may have Normal, Off
Road, and Tow/Haul.
Mode Activation
To activate and deactivate Tow/Haul
turn the Drive Mode knob to the left.
For activation of modes other than
Tow/Haul, turn the Drive Mode knob
to the right.

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 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
246 Driving and Operating
used, ACC can be turned back on.
Disabling the TCS or StabiliTrak/
ESC system will disengage and
prevent engagement of ACC.
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.
(Continued)
Warning (Continued)
.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