towing tips GMC SIERRA 2021 Owner's Manual

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
212 Driving and Operating
Filling a Portable Fuel Container . . . . . . . 288
Trailer Towing
General Towing Information . . . . . . . . . . 288
Driving Characteristics andTowing Tips . . . . . . . . . . . . . . . . . . . . . . . . . 288
Trailer Towing . . . . . . . . . . . . . . . . . . . . . . . . . 293
Towing Equipment . . . . . . . . . . . . . . . . . . . . 296
Trailer Sway Control (TSC) . . . . . . . . . . . . 306
Trailering App . . . . . . . . . . . . . . . . . . . . . . . . . 307
Conversions and Add-Ons
Add-On Electrical Equipment . . . . . . . . . . . 318
Adding a Snow Plow or Similar Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
Pickup Conversion to Chassis Cab . . . . . 320
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.
.Combine several trips into a single trip.
.Replace the vehicle's tires with the same
TPC Spec number molded into the tire's
sidewall near the size.
.Follow recommended scheduled
maintenance.
Distracted Driving
Distraction comes in many forms and can
take your focus from the task of driving.
Exercise good judgment and do not let other
activities divert your attention away from
the road. Many local governments have
enacted laws regarding driver distraction.
Become familiar with the local laws in
your area.
To avoid distracted driving, keep your eyes
on the road, keep your hands on the
steering wheel, and focus your attention on
driving.
.Do not use a phone in demanding driving
situations. Use a hands-free method to
place or receive necessary phone calls.
.Watch the road. Do not read, take notes,
or look up information on phones or
other electronic devices.
.Designate a front seat passenger to
handle potential distractions.
.Become familiar with vehicle features
before driving, such as programming
favorite radio stations and adjusting
climate control and seat settings. Program
all trip information into any navigation
device prior to driving.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 223
pressures (4). For more information on
tires and inflation seeTires0360 and
Tire Pressure 0367.
There is also important loading
information on the vehicle Certification/
Tire label. It may show the Gross
Vehicle Weight Rating (GVWR) and the
Gross Axle Weight Rating (GAWR) for
the front and rear axles. See
“Certification/Tire Label” later in this
section.
“Steps for Determining Correct Load Limit–
1.
Locate the statement "The combined
weight of occupants and cargo
should never exceed XXX kg or
XXX lbs." on your vehicle’s placard.
2.Determine the combined weight of
the driver and passengers that will
be riding in your vehicle.
3.Subtract the combined weight of the
driver and passengers from XXX kg
or XXX lbs.
4.The resulting figure equals the
available amount of cargo and
luggage load capacity. For example, if the "XXX" amount equals 1400 lbs.
and there will be five 150 lb
passengers in your vehicle, the
amount of available cargo and
luggage load capacity is 650 lbs.
(1400-750 (5 x 150) = 650 lbs.)
5.Determine the combined weight of
luggage and cargo being loaded on
the vehicle. That weight may not
safely exceed the available cargo and
luggage load capacity calculated in
Step 4.
6.If your vehicle will be towing a
trailer, load from your trailer will be
transferred to your vehicle. Consult
this manual to determine how this
reduces the available cargo and
luggage load capacity of your
vehicle.”
See Trailer Towing 0293 for important
information on towing a trailer, towing
safety rules, and trailering tips.
Example 1
1. Vehicle Capacity Weight for Example 1
= (453 kg) (1,000 lb)
2. Subtract Occupant Weight @ 68 kg (150 lb) × 2 = 136 kg (300 lb)
3. Available Occupant and Cargo Weight = 317 kg (700 lb)

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
236 Driving and Operating
Retained Accessory Power (RAP)
When the ignition is turned from on to off,
the following features (if equipped) will
continue to function for up to 10 minutes,
or until the driver door is opened. These
features will also work when the ignition is
in RUN or ACC/ACCESSORY:
.Infotainment System
.Power Windows (during RAP this
functionality will be lost when any door
is opened)
.Sunroof (during RAP this functionality will
be lost when any door is opened)
.Auxiliary Power Outlet
.Audio System
.OnStar System
Shifting Into Park
{Warning
It can be dangerous to get out of the
vehicle if the shift lever is not fully in
P (Park) with the parking brake firmly set.
The vehicle can roll. If you have left the
engine running, the vehicle can move
suddenly. You or others could be injured.(Continued)
Warning (Continued)
To be sure the vehicle will not move,
even when you are on fairly level ground,
use the steps that follow. With
four-wheel drive, if the transfer case is in
N (Neutral), the vehicle will be free to
roll, even if the shift lever is in P (Park).
Be sure the transfer case is in a drive
gear. If towing a trailer, seeDriving
Characteristics and Towing Tips 0288.
1. Hold the brake pedal down, then set the parking brake. See Electric Parking Brake
0 247.
2. Move the shift lever into the P (Park) position by pulling the shift lever toward
you and moving it up as far as it will go.
3. Be sure the transfer case (if equipped) is in a drive gear –not in N (Neutral).
4. Turn the ignition off. For Key Access, push the ignition key in, towards the
steering column and then turn the
ignition off.
5. For Key Access, remove the key and take it with you. If you can leave the vehicle
with the ignition key in your hand, the
vehicle is in P (Park). For Keyless Access, take the Remote
Keyless Entry (RKE) transmitter with you.Leaving the Vehicle with the Engine
Running
{Warning
It can be dangerous to leave the vehicle
with the engine running. The vehicle
could move suddenly if the shift lever is
not fully in P (Park) with the parking
brake firmly set.
If you have four-wheel drive and the
transfer case is in N (Neutral), the vehicle
will be free to roll, even if the shift lever
is in P (Park). So be sure the transfer case
is in a drive gear
–not in N (Neutral).
And, if you leave the vehicle with the
engine running, it could overheat and
even catch fire. You or others could be
injured. Do not leave the vehicle with the
engine running unless you have to.
If you have to leave the vehicle with the
engine running, be sure the vehicle is in
P (Park) and the parking brake is firmly set
before you leave it. After moving the shift
lever into P (Park), hold the regular brake

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 239
If parking on a hill and pulling a trailer, see
Driving Characteristics and Towing Tips
0288.
Automatic Transmission
If equipped, there is an electronic shift lever
position indicator within the instrument
cluster. This display comes on when the
ignition is in ACC/ACCESSORY, on or
service mode.
There are several different positions for the
shift lever.
See Driver Mode Control 0251 and “Range
Selection Mode” underManual Mode 0241.
P : This position locks the rear wheels. Use
P (Park) when starting the engine because
the vehicle cannot move easily. When parked on a hill, especially when the
vehicle has a heavy load, you might notice
an increase in the effort to shift out of
P (Park). See
“Torque Lock” underShifting
Into Park 0236.
{Warning
It is dangerous to get out of the vehicle
if the shift lever is not fully in P (Park)
with the parking brake firmly set. The
vehicle can roll.
Do not leave the vehicle when the engine
is running. If you have left the engine
running, the vehicle can move suddenly.
You or others could be injured. To be
sure the vehicle will not move, even
when you are on fairly level ground,
always set the parking brake and move
the shift lever to P (Park). See Shifting
Into Park 0236 and
Driving Characteristics and Towing Tips
0 288.
{Warning
If equipped with four-wheel drive, the
vehicle will be free to roll if the transfer
case is in N (Neutral), even when the shift
lever is in P (Park). You or someone else
could be seriously injured. Be sure the
transfer case is in a drive gear —2
m, 4m,
or 4
n— or set the parking brake before
placing the transfer case in N (Neutral).
See Four-Wheel Drive 0242.
R : Use this gear to back up.
Caution
Shifting to R (Reverse) while the vehicle is
moving forward could damage the
transmission. The repairs would not be
covered by the vehicle warranty. Shift to
R (Reverse) only after the vehicle is
stopped.
To rock the vehicle back and forth to get
out of snow, ice, or sand without damaging
the transmission, see If the Vehicle Is Stuck
0 221.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
248 Driving and Operating
3. Press the EPB switch momentarily.
The EPB is released when the red parking
brake status light is off.
If the amber service parking brake warning
light is on, release the EPB by pressing and
holding the EPB switch. Continue to hold the
switch until the red parking brake status
light is off. If either light stays on after
release is attempted, see your dealer.
Caution
Driving with the parking brake on can
overheat the brake system and cause
premature wear or damage to brake
system parts. Make sure that the parking
brake is fully released and the brake
warning light is off before driving.
If you are towing a trailer and parking on a
hill, see Driving Characteristics and Towing
Tips 0288.
Automatic EPB Release
The EPB will automatically release if the
vehicle is running, placed into gear, and an
attempt is made to drive away. Avoid rapid
acceleration when the EPB is applied, to
preserve parking brake lining life.
Brake Assist
Brake Assist detects rapid brake pedal
applications due to emergency braking
situations and provides additional braking to
activate the Antilock Brake System (ABS) if
the brake pedal is not pushed hard enough
to activate ABS normally. Minor noise, brake
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 Driving
0 213.
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.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
288 Driving and Operating
{Warning
If a fire starts while you are refueling, do
not remove the fill nozzle. Shut off the
flow of fuel by shutting off the pump or
by notifying the station attendant. Leave
the area immediately.
Caution
If a new fuel cap is needed, get the right
type of cap from your dealer. The wrong
type of fuel cap may not fit properly,
may turn on the malfunction indicator
lamp, and could damage the fuel system
and emissions system. SeeMalfunction
Indicator Lamp (Check Engine Light) 0115.
Filling a Portable Fuel Container
{Warning
Never fill a portable fuel container while
it is in the vehicle. Static electricity
discharge from the container can ignite
the fuel vapor. You or others could be
badly burned and the vehicle could be
damaged. To help avoid injury to you
and others:
.Dispense fuel only into approved
containers.
.Do not fill a container while it is
inside a vehicle, in a vehicle's trunk, in
a pickup bed, or on any surface other
than the ground.
.Bring the fill nozzle in contact with
the inside of the fill opening before
operating the nozzle. Maintain contact
until filling is complete.
.Keep sparks, flames, and smoking
materials away from fuel.
.Avoid using electronic devices while
pumping fuel.
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
Vehicle 0394. To tow the vehicle behind
another vehicle such as a motor home, see
Recreational Vehicle Towing 0395.
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 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
(Continued)

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 289
Warning (Continued)
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.
.Vehicles can tow in D (Drive). Tow/Haul
Mode is recommended for heavier trailers.
SeeTow/Haul Mode 0242. If the
transmission downshifts too often, a
lower gear may be selected using Manual
Mode. See Manual Mode 0241.
If equipped, the following driver assistance
features should be turned off when towing
a trailer:
.Adaptive Cruise Control (ACC)
.Super Cruise Control
.Lane Keep Assist (LKA)
.Park Assist
.Automatic Parking Assist (APA)
.Reverse Automatic Braking (RAB)
If equipped, the following driver assistance
features should be turned to alert or off
when towing a trailer:
.Automatic Emergency Braking (AEB)
.Intelligent Brake Assist (IBA)
.Front Pedestrian Braking (FPB)
If equipped with Lane Change Alert (LCA),
the LCA detection zones that extend back
from the side of the vehicle do not move
further back when a trailer is towed. Use
caution while changing lanes when towing a
trailer.
If equipped with Rear Cross Traffic Alert
(RCTA), use caution while backing up when
towing a trailer, as the RCTA detection zones
that extend out from the back of the vehicle
do not move further back when a trailer is
towed.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
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Driving and Operating 293
Trailer Towing
If equipped with a diesel engine, see the
Duramax diesel supplement.
Caution
Towing a trailer improperly can damage
the vehicle and result in costly repairs
not covered by the vehicle warranty. To
tow a trailer correctly, follow the
directions in this section and see your
dealer for important information about
towing a trailer with the vehicle.
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.
Trailer Weight
{Warning
Never exceed the towing capacity for
your vehicle.
Safe trailering requires monitoring the
weight, speed, altitude, road grades, outside
temperature, and how frequently the vehicle
is used to tow a trailer.
Trailer Weight Ratings
When towing a trailer, the combined weight
of the vehicle, vehicle contents, trailer, and
trailer contents must be below all of the
maximum weight ratings for the vehicle,
including:
.GCWR: Gross Combined Weight Rating
.GVWR: Gross Vehicle Weight Rating
.Maximum Trailer Weight Rating
.GAWR-RR: Gross Axle Weight Rating-Rear
.Maximum Trailer Tongue Weight Rating
See “Weight-Distributing Hitch and
Adjustment” underTowing Equipment 0296
to determine if equalizer bars are required
to obtain the maximum trailer weight
rating. See
“Trailer Brakes” underTowing
Equipment 0296 to determine if brakes are
required based on your trailer's weight.
The only way to be sure the weight is not
exceeding any of these ratings is to weigh
the tow vehicle and trailer combination,
fully loaded for the trip, getting individual
weights for each of these items.
A trailering information label on the B-pillar
shows tow rating information for the
vehicle.
{Warning
You and others could be seriously injured
or killed if the trailer is too heavy or the
trailer brakes are inadequate for the load.
The vehicle may be damaged, and the
repairs would not be covered by the
vehicle warranty.
Only tow a trailer if all the steps in this
section have been followed. Ask your
dealer for advice and information about
towing a trailer.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./Cana-
da/Mexico-14632426) - 2021 - CRC - 11/5/20
Index 451
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145
DoorAjar Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Delayed Locking . . . . . . . . . . . . . . . . . . . . . . . . 22
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Power Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Drive Belt Routing, Engine . . . . . . . . . . . . . . . 427
Driver
Teen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Driver Assistance Systems . . . . . . . . . . . . . . . 265
Driver Information Center (DIC) . . . . . . 124, 125
Driver Mode Control . . . . . . . . . . . . . . . . . . . . . . 251
Driver Mode Control Light . . . . . . . . . . . . . . . . 121
Driving Assistance Systems . . . . . . . . . . . . . . . . . . . . 274
Better Fuel Economy . . . . . . . . . . . . . . . . . . . 212
Characteristics and Towing Tips . . . . . . . . 288
Defensive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
Hill and Mountain Roads . . . . . . . . . . . . . . 219
If the Vehicle is Stuck . . . . . . . . . . . . . . . . . 221
Impaired . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
Loss of Control . . . . . . . . . . . . . . . . . . . . . . . . 215
Off-Road . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Off-Road Recovery . . . . . . . . . . . . . . . . . . . . . 214
Vehicle Load Limits . . . . . . . . . . . . . . . . . . . . 222
Wet Roads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 Dual Automatic Climate Control
System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
E
E85 or FlexFuel . . . . . . . . . . . . . . . . . . . . . . . . . . 284
Electric Brake Boost . . . . . . . . . . . . . . . . . . . . . . 246
Electric Parking Brake . . . . . . . . . . . . . . . . . . . . 247
Electric Parking Brake Light . . . . . . . . . . . . . . . 117
Electrical Equipment, Add-On . . . . . . . . . . . . .318
Electrical System
Engine Compartment Fuse Block . . . . . . . 353
Fuses and Circuit Breakers . . . . . . . . . . . . . 353
Instrument Panel Fuse Block . . . . . . 357, 358
Overload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352
Electronic Stability Control (ESC) Off Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Emergency
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . 334
Check Light (Malfunction Indicator) . . . . . 115
Compartment Overview . . . . . . . . . . . . . . . . 325
Coolant Temperature Gauge . . . . . . . . . . . . 112
Coolant Temperature Warning Light . . . . 121
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . 335
Drive Belt Routing . . . . . . . . . . . . . . . . . . . . . 427 Engine (cont'd)
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238
Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 340
Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 332
Oil Pressure Gauge . . . . . . . . . . . . . . . . . . . . . 111
Oil Pressure Light . . . . . . . . . . . . . . . . . . . . . . 122
Overheated Protection
Operating Mode . . . . . . . . . . . . . . . . . . . . . 340
Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
Power Messages . . . . . . . . . . . . . . . . . . . . . . . . 131
Running While Parked . . . . . . . . . . . . . . . . . 238
Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
Engine Air Filter Life System . . . . . . . . . . . . . 333
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Equipment, Towing . . . . . . . . . . . . . . . . . . . . . . 296
Event Data Recorders . . . . . . . . . . . . . . . . . . . . 438
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Extended Parking . . . . . . . . . . . . . . . . . . . . . . . . 238
Extender, Seat Belt . . . . . . . . . . . . . . . . . . . . . . . 59
Exterior Cargo Lamps . . . . . . . . . . . . . . . . . . . . 144
Exterior Lamp Controls . . . . . . . . . . . . . . . . . . . 139
Exterior Lamps Off Reminder . . . . . . . . . . . . . 141
Exterior Lighting Battery Saver . . . . . . . . . . .147