2020 GMC SIERRA On star

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 185
Driving and
Operating
Driving Information
Driving for Better FuelEconomy . . . . . . . . . . . . . . . . . . . . 186
Distracted Driving . . . . . . . . . . . . 187
Defensive Driving . . . . . . . . . . . . . 187
Drunk Driving . . . . . . . . . . . . . . . . . 188
Control of a Vehicle . . . . . . . . . . . 188
Braking . . . . . . . . . . . . . . . . . . . . . . . 188
Steering . . . . . . . . . . . . . . . . . . . . . . 188
Off-Road Recovery . . . . . . . . . . . 190
Loss of Control . . . . . . . . . . . . . . . 190
Off-Road Driving . . . . . . . . . . . . . 191
Driving on Wet Roads . . . . . . . . 196
Hill and Mountain Roads . . . . . 197
Winter Driving . . . . . . . . . . . . . . . . 197
If the Vehicle Is Stuck . . . . . . . . 199
Vehicle Load Limits . . . . . . . . . . . 200
Truck-Camper Loading Information . . . . . . . . . . . . . . . . . . 206
Starting and Operating
New Vehicle Break-In . . . . . . . . . 208
Ignition Positions (KeylessAccess) . . . . . . . . . . . . . . . . . . . . . 208 Ignition Positions (Key
Access) . . . . . . . . . . . . . . . . . . . . . 210
Starting the Engine . . . . . . . . . . . 212
Stop/Start System . . . . . . . . . . . . 213
Engine Heater . . . . . . . . . . . . . . . . 215
Retained Accessory Power (RAP) . . . . . . . . . . . . . . . . 217
Shifting Into Park . . . . . . . . . . . . . 217
Shifting out of Park . . . . . . . . . . . 218
Parking over Things That Burn . . . . . . . . . . . . . . . . . . . 219
Active Fuel Management . . . . . 219
Extended Parking . . . . . . . . . . . . 219
Engine Exhaust
Engine Exhaust . . . . . . . . . . . . . . 220
Running the Vehicle While Parked . . . . . . . . . . . . . . . . . . . . . . 220
Automatic Transmission
Automatic Transmission . . . . . . 221
Manual Mode . . . . . . . . . . . . . . . . . 224
Tow/Haul Mode . . . . . . . . . . . . . . . 226
Drive Systems
Four-Wheel Drive . . . . . . . . . . . . . 227
Brakes
Electric Brake Boost . . . . . . . . . . 232
Antilock BrakeSystem (ABS) . . . . . . . . . . . . . . . 232
Electric Parking Brake . . . . . . . . 233 Brake Assist . . . . . . . . . . . . . . . . . . 234
Hill Start Assist (HSA) . . . . . . . . 235
Ride Control Systems
Traction Control/Electronic
Stability Control . . . . . . . . . . . . . 235
Hill Descent Control (HDC) . . . 237
Driver Mode Control . . . . . . . . . . 238
Limited-Slip Differential . . . . . . . 242
Locking Rear Axle . . . . . . . . . . . . 243
Cruise Control
Cruise Control . . . . . . . . . . . . . . . . 243
Adaptive Cruise Control (1500 Series) . . . . . . . . . . . . . . . . . . . . . . 245
Driver Assistance Systems
Driver Assistance Systems . . . 256
Assistance Systems forParking or Backing . . . . . . . . . . 257
Assistance Systems for Driving . . . . . . . . . . . . . . . . . . . . . . 268
Forward Collision Alert (FCA) System . . . . . . . . . . . . . . . . . . . . . . 268
Automatic Emergency Braking (AEB) . . . . . . . . . . . . . . . 270
Front Pedestrian Braking (FPB) System (1500
Series) . . . . . . . . . . . . . . . . . . . . . . 272
Side Blind Zone Alert (SBZA) . . . . . . . . . . . . . . . . 274

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 191
Defensive drivers avoid most skids
by taking reasonable care suited to
existing conditions, and by not
overdriving those conditions. But
skids are always possible.
If the vehicle starts to slide, follow
these suggestions:
.Ease your foot off the
accelerator pedal and steer the
way you want the vehicle to go.
The vehicle may straighten out.
Be ready for a second skid if it
occurs.
. Slow down and adjust your
driving according to weather
conditions. Stopping distance
can be longer and vehicle
control can be affected when
traction is reduced by water,
snow, ice, gravel, or other
material on the road. Learn to
recognize warning clues —such
as enough water, ice, or packed
snow on the road to make a
mirrored surface —and slow
down when you have any doubt. .
Try to avoid sudden steering,
acceleration, or braking,
including reducing vehicle speed
by shifting to a lower gear. Any
sudden changes could cause
the tires to slide.
Remember: Antilock brakes help
avoid only the braking skid.
Off-Road Driving
Four-wheel-drive vehicles can be
used for off-road driving. Vehicles
without four-wheel drive and
vehicles not equipped with All
Terrain (AT) or On-Off Road (OOR)
tires must not be driven off-road
except on a level, solid surface. For
contact information about the
original equipment tires, see the
warranty manual.
One of the best ways for successful
off-road driving is to control the
speed.
{Warning
When driving off-road, bouncing
and quick changes in direction
can easily throw you out of
position. This could cause you to
lose control and crash. You and
your passengers should always
wear seat belts.
Before Driving Off-Road
. Have all necessary maintenance
and service work completed.
. Fuel the vehicle, fill fluid levels,
and check inflation pressure in
all tires, including the spare,
if equipped.
. Read all the information about
four-wheel-drive vehicles in this
manual.
. Remove any underbody air
deflector, if equipped. Re-attach
the air deflector after off-road
driving.
. Know the local laws that apply to
off-road driving.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
194 Driving and Operating
Warning (Continued)
descending a hill and use a low
gear to keep vehicle speed under
control.
If a brake fade condition is detected,
a DIC warning message is
displayed. Adjust brake pedal use
and shift to a lower transmission
gear to reduce braking.
If the brakes continue to fade to a
severe condition, additional DIC
messages are displayed. The brake
system warning light will illuminate,
and the vehicle speed may be
limited. See Brake System Warning
Light 0140.
If the vehicle stalls on a hill:
1. Apply the brakes to stop the vehicle, and then apply the
parking brake. 2. Shift into P (Park) and then
restart the engine.
.If driving uphill when the
vehicle stalls, shift to
R (Reverse), release the
parking brake, and back
straight down.
. Never try to turn the vehicle
around. If the hill is steep
enough to stall the vehicle,
it is steep enough to cause
it to roll over.
. If you cannot make it up the
hill, back straight down
the hill.
. Never back down a hill in
N (Neutral) using only the
brake. The vehicle can roll
backward quickly and you
could lose control.
. If driving downhill when the
vehicle stalls, shift to a
lower gear, release the
parking brake, and drive
straight down the hill. 3. If the vehicle cannot be
restarted after stalling, set the
parking brake, shift into
P (Park), and turn the
vehicle off.
3.1. Leave the vehicle and
seek help.
3.2. Stay clear of the path the vehicle would take if it
rolled downhill.
. Avoid turns that take the vehicle
across the incline of the hill.
A hill that can be driven straight
up or down might be too steep to
drive across. Driving across an
incline puts more weight on the
downhill wheels, which could
cause a downhill slide or a
rollover.
. Surface conditions can be a
problem. Loose gravel, muddy
spots, or even wet grass can
cause the tires to slip sideways,
downhill. If the vehicle slips
sideways, it can hit something
that will trip it —a rock, a rut,
etc. —and roll over.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 195
.Hidden obstacles can make the
steepness of the incline more
severe. If a rock is driven across
with the uphill wheels, or if the
downhill wheels drop into a rut
or depression, the vehicle can tilt
even more.
. If an incline must be driven
across, and the vehicle starts to
slide, turn downhill. This should
help straighten out the vehicle
and prevent the side slipping.
{Warning
Getting out of the vehicle on the
downhill side when stopped
across an incline is dangerous.
If the vehicle rolls over, you could
be crushed or killed. Always get
out on the uphill side of the
vehicle and stay well clear of the
rollover path.
Driving in Mud, Sand, Snow,
or Ice
Use a low gear when driving in mud
—the deeper the mud, the lower
the gear. Keep the vehicle moving
to avoid getting stuck.
Traction changes when driving on
sand. On loose sand, such as on
beaches or sand dunes, the tires
tend to sink into the sand. This
affects steering, accelerating, and
braking. Drive at a reduced speed
and avoid sharp turns or abrupt
maneuvers.
Traction is reduced on hard packed
snow and ice and it is easy to lose
control. Reduce vehicle speed when
driving on hard packed snow
and ice.
{Warning
Driving on frozen lakes, ponds,
or rivers can be dangerous. Ice
conditions vary greatly and the
vehicle could fall through the ice;
(Continued)
Warning (Continued)
you and your passengers could
drown. Drive your vehicle on safe
surfaces only.
Driving in Water
{Warning
Driving through rushing water can
be dangerous. Deep water can
sweep your vehicle downstream
and you and your passengers
could drown. If it is only shallow
water, it can still wash away the
ground from under your tires.
Traction could be lost, and the
vehicle could roll over. Do not
drive through rushing water.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
196 Driving and Operating
Caution
Do not drive through standing
water if it is deep enough to cover
the wheel hubs, axles, or exhaust
pipe. Deep water can damage the
axle and other vehicle parts.
If the standing water is not too deep,
drive through it slowly. At faster
speeds, water can get into the
engine and cause it to stall. Stalling
can occur if the exhaust pipe is
under water. Do not turn off the
ignition when driving through water.
If the exhaust pipe is under water,
the engine will not start. When going
through water, the brakes get wet
and it may take longer to stop. See
“Driving on Wet Roads” later in this
section.
After Off-Road Driving
Remove any brush or debris that
has collected on the underbody or
chassis, or under the hood. These
accumulations can be a fire hazard.
Re-install underbody air deflector
and air dam if removed. After operation in mud or sand,
have the brake linings cleaned and
checked. These substances can
cause glazing and uneven braking.
Check the body structure, driveline,
steering, suspension, wheels, tires,
and exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
More frequent maintenance service
is required. See the
Maintenance
Schedule 0442.
Driving on Wet Roads
Rain and wet roads can reduce
vehicle traction and affect your
ability to stop and accelerate.
Always drive slower in these types
of driving conditions and avoid
driving through large puddles and
deep-standing or flowing water.
{Warning
Wet brakes can cause crashes.
They might not work as well in a
quick stop and could cause
pulling to one side. You could
lose control of the vehicle.
After driving through a large
puddle of water or a car/vehicle
wash, lightly apply the brake
pedal until the brakes work
normally.
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be
very cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water
can build up under the vehicle's
tires so they actually ride on the
water. This can happen if the road is

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 199
If it takes time for help to arrive,
when running the engine, push the
accelerator pedal slightly so the
engine runs faster than the idle
speed. This keeps the battery
charged to restart the vehicle and to
signal for help with the headlamps.
Do this as little as possible, to
save fuel.
If the Vehicle Is Stuck
Slowly and cautiously spin the
wheels to free the vehicle when
stuck in sand, mud, ice, or snow.
See“Rocking the Vehicle to Get It
Out” later in this section.
The Traction Control/Electronic
Stability Control can often help to
free a stuck vehicle. See Traction
Control/Electronic Stability Control
0 235. If TC/ESC cannot free the
vehicle, see “Rocking the Vehicle to
Get it Out” following.
{Warning
If the vehicle's tires spin at high
speed, they can explode, and you
or others could be injured. The
vehicle can overheat, causing an
engine compartment fire or other
damage. Spin the wheels as little
as possible and avoid going
above 56 km/h (35 mph).
For information about using tire
chains on the vehicle, see Tire
Chains 0404.
Rocking the Vehicle to Get
It Out
Caution
Do not hold the steering wheel at
full rotation for more than
15 seconds and/or at an elevated
RPM. Damage may occur to the
power steering system and there
may be loss of power steering
assist. Turn the steering wheel left and
right to clear the area around the
front wheels. Then make sure the
wheels are pointed straight ahead.
For four-wheel-drive vehicles, shift
into Four-Wheel Drive High. Turn
the TCS off. Shift back and forth
between R (Reverse) and a forward
gear, spinning the wheels as little as
possible. To prevent transmission
wear, wait until the wheels stop
spinning before shifting gears.
Slowly spinning the wheels in the
forward and reverse directions
causes a rocking motion that could
free the vehicle. If that does not get
the vehicle out after a few tries, it
might need to be towed out. See
Towing the Vehicle
0424. Recovery
hooks can be used, if the vehicle
has them.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
208 Driving and Operating
Starting and
Operating
New Vehicle Break-In
Caution
The vehicle does not need an
elaborate break-in. But it will
perform better in the long run if
you follow these guidelines:. Keep the vehicle speed at
88 km/h (55 mph) or less for
the first 805 km (500 mi).
. Do not drive at any one
constant speed, fast or slow,
for the first 805 km (500 mi).
Do not make full-throttle
starts. Avoid downshifting to
brake or slow the vehicle.
. Avoid making hard stops for
the first 322 km (200 mi) or
so. During this time the new
brake linings are not yet
broken in. Hard stops with
new linings can mean
(Continued)
Caution (Continued)
premature wear and earlier
replacement. Follow this
breaking-in guideline every
time you get new brake
linings.
. Do not tow a trailer during
break-in. See Trailer Towing
0 292 for the trailer towing
capabilities of the vehicle
and more information.
Following break-in, engine speed
and load can be gradually
increased.
Ignition Positions
(Keyless Access)
Vehicles equipped with Keyless
Access have pushbutton starting.
The Remote Keyless Entry (RKE)
transmitter must be in the vehicle for
the system to operate. If the
pushbutton start is not working, the
vehicle may be near a strong radio
antenna signal causing interference
to the Keyless Access system. See
Remote Keyless Entry (RKE)
System Operation (Key Access)
0 13 or