fuel GMC SIERRA 2020 Service Manual

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
286 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) 0138.
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.
(Continued)
Warning (Continued)
.Keep sparks, flames, and
smoking materials away
from fuel.
. Do not use electronic
devices while pumping fuel.

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
292 Driving and Operating
the drive mode that is
appropriate for the road
conditions.
Caution
If the vehicle tires begin to spin
and the vehicle begins to slide
toward the water, remove your
foot from the accelerator pedal
and apply the brake pedal. Seek
help to have the vehicle towed up
the ramp.
Maintenance when Trailer
Towing
The vehicle needs service more
often when used to tow trailers. See
Maintenance Schedule0442. It is
especially important to check the
engine oil, axle lubricant, belts,
cooling system, and brake system
before and during each trip.
Check periodically to see that all
nuts and bolts on the trailer hitch
are tight.
Engine Cooling When Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. See Engine Overheating
0 351.
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

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 293
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.
Gross Combined Weight
Rating (GCWR)
GCWR is the total allowable weight
of the completely loaded vehicle
and trailer including any fuel,
passengers, cargo, equipment, and
accessories. Do not exceed the
GCWR for your vehicle. The GCWR
for the vehicle is on the Trailering
Information Label.
To check that the weight of the
vehicle and trailer are within the
GCWR for the vehicle, follow these
steps:
1. Start with the "curb weight" from the Trailering Information
Label.
2. Add the weight of the trailer loaded with cargo and ready
for the trip.
3. Add the weight of all passengers.
4. Add the weight of all cargo in the vehicle.
5. Add the weight of hitch hardware such as a draw bar,
ball, load equalizer bars,
or sway bars.
6. Add the weight of any accessories or aftermarket
equipment added to the
vehicle.
The resulting weight cannot exceed
the GCWR value on the Trailering
Information Label.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
304 Driving and Operating
Trailer Lamps
Always check that all trailer lamps
are working at the beginning of each
trip, and periodically on longer trips.
If equipped, the Trailering App will
monitor the RH turn/brake lamp
circuit, LH turn/brake lamp circuit,
running lamp circuit, and reverse
lamp circuits on the trailer. DIC
messages and Trailering App alerts
may be displayed if lighting circuit
issues are detected on the trailer.
Pressing START LIGHT TEST in the
Trailering App automatically
activates the trailer lamps. The
Trailering App is not a substitute for
manually inspecting your trailer
lamps. SeeTrailering App 0310.
Turn Signals When Towing a
Trailer
When properly connected, the trailer
turn signals will illuminate to indicate
the vehicle is turning, changing
lanes, or stopping. When towing a
trailer, the arrows on the instrument cluster will illuminate even if the
trailer is not properly connected or
the bulbs are burned out.
Tow/Haul Mode
For instructions on how to enter
Tow/Haul Mode, see
Driver Mode
Control 0238.
Tow/Haul assists when pulling a
heavy trailer or a large or 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 “Trailer Weight ”under Trailer
Towing 0292.
Tow/Haul Mode is most useful when
towing a heavy trailer or carrying a
large or heavy load:
. Through rolling terrain.
. In stop-and-go traffic.
. In busy parking lots.
Operating the vehicle in Tow/Haul
Mode when lightly loaded or not
towing will not cause damage; however, it is not recommended and
may result in unpleasant engine and
transmission driving characteristics,
heavy or light steering efforts, and
reduced fuel economy.Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for use with electric trailer brakes or
most electric over hydraulic trailer
brake systems. These instructions
apply to both types of electric trailer
brakes.
This symbol is on the Trailer Brake
Control Panel on vehicles with an
ITBC system. The power output to
the trailer brakes is proportional to
the amount of vehicle braking. This

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
314 Driving and Operating
.Vehicle Hitch Height: 10 cm
(3.9 in) –100 cm (39.3 in).
Measure from ground to top
of coupler.
. Vehicle Hitch Length: 10 cm
(3.9 in) –100 cm (39.3 in).
Measure from hitch receiver
to center of ball.
3. If trailer dimensions are out of range, this feature will be
unavailable. Select OK to
return.
4. Ensure rear trailer camera is connected.
5. Follow instructions to drive forward to complete calibration.
6. Return to the vehicle to complete the setup..
Status View
The Status view shows:
.Truck
. Connections
. Trailer
. Maintenance
. Cameras Upon entry, the most recent items
will be shown. Select MORE to view
all options.
Truck
1. Transmission Fluid
Temperature
2. Average Fuel Economy with Trailer Profile
Average Fuel Economy
Touch to view the average fuel
economy of the vehicle while the
Trailer Profile is active. Transmission Temperature
View the temperature of the
transmission fluid by looking at the
graphic. The graphic will indicate a
dangerous level if the temperature
is at 130 °C–150 °C (270 °F–300 °F).
Connections
1. Light Test Start Button
2. Trailer Electrical Diagnostics
Connections OK
If all of the trailer connections are
detected (Running Lights, Left Turn
Signal Light, Right Turn Signal

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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Driving and Operating 317
Cameras
1. Rear Trailer Not Connected/Preview, if equipped
2. Interior Trailer Not Connected/Preview,
if equipped
3. Transparent Trailer Not Set Up/Preview, if equipped
The Cameras Status view displays
status of trailer cameras.
Touch a connected camera to
preview the camera image.
Touch the Transparent Trailer option
to enter Transparent Trailer Setup if
setup is not complete.
Guest Trailer Status View
Touch the Guest Trailer Profile for
the status views.
The Guest Trailer Profile Status
view shows:
.Truck
. Trailer
. Connections
. Cameras, if equipped
The Trailer Status view displays
mileage information. Touch to edit,
and follow the on-screen prompts.
Mileage and fuel economy will reset
after the trailer disconnects. The
Cameras Status view displays
status of trailer cameras. Touch a
connected camera to preview the
camera image.
Checklist View
This view shows the recommended
steps to take before towing a trailer.
Touch the box next to each item if
that step has been completed. Touch
pto access a detailed
view of each step. Within each
detailed view, touch Next and
Previous to navigate between steps.
Touch Clear All to clear the
completed statuses from all items in
the current checklist.
The checklist is unique to the Trailer
Profile based on hitch type; for
example, the steps involve different
details between conventional,
gooseneck, and fifth-wheel hitch
types.
Custom Checklist Items
For each of the Trailer Profile
checklists, there is an option to
create custom items to view in the
checklist. The custom item will
appear at the bottom of the
checklist.
Guest Trailer and No Trailer
Connected
If Guest Trailer Profile is active or if
no trailer is connected, the checklist
will show all of the checklists

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
318 Driving and Operating
associated with Custom Trailer
Profiles in addition to default
checklists.
Trailers View
Touch the Trailers tab to view,
activate, create, edit, or delete
Trailer Profiles.
If a trailer is connected, touch the
Trailer Profile name to activate a
Trailer Profile.
There can be up to five Custom
Trailer Profiles on the vehicle.
The Custom Trailer Profiles and
Guest Trailer are in order of the
most frequently used.
All personalization features are
based on the settings for each
driver in vehicle personalization.
The list of Trailer Profiles is based
on vehicle personalization settings.
Guest Trailer
If the Guest Trailer Profile is the
active Trailer Profile, trailer
detection, connections status, theft,
and the Tow/Haul reminder alerts
can be sent. The system will nottrack total mileage or fuel economy,
but the system will track trip mileage
and fuel economy if the Guest
Trailer Profile is active. The Trailer
Tire Pressure Monitoring System or
maintenance reminders cannot be
set up for a Guest Trailer Profile.
The Guest Trailer Profile cannot be
edited.
Touch
pto learn more about the
Guest Trailer option.
No Trailer Connected
When there is no trailer connected,
Trailer Profiles cannot be activated
but most options can be edited.
Trailer Brake Gain Memory
The system can memorize the brake
gain setting of a Trailer Profile or a
Guest Trailer Profile. When a Trailer
Profile or Guest Trailer Profile is
selected, and a brake gain setting is
set for that Trailer Profile, a quick
notice will appear to indicate that
the system has recalled that
profile’s brake gain setting. If a Trailer Profile is already active
and the brake gain setting had been
set for that Trailer Profile, the quick
notice will trigger whenever the
ignition is turned on.
If there was an error in setting the
brake gain for a Trailer Profile, there
will be a notification. This pop-up
will not appear if the Guest Trailer
Profile is active or if there is no
trailer connected.
Trailer brake gain should be set for
a specific trailering condition and
must be adjusted anytime vehicle
loading, trailer loading, or road
surface conditions change.
Editing a Trailer Profile
Trailer Profile View
Touch to edit any of the following
options in the Trailer Profile view:
.
Trailer Name
. Towing Assistance Setup
. Tire Pressure Setup
. Trailer Maintenance
. Mileage

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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Driving and Operating 319
.Average Fuel Economy
. Reverse Lights Alert
. Electric Brakes Alert
Touch Save to save the new value
to the Trailer Profile. Touching Back
will still save the previously entered
information.
Trailer Name
Touch to edit the Trailer Profile’s
name. Use at least one character
and no spaces. Touch Save.
Towing Assistance Setup
A trailer should be connected to
complete this portion of profile
setup.
Touch to set up the Transparent
Trailer feature for the Trailer Profile.
See "Transparent Trailer Setup"
under "Towing Assistance" for
details on the setup.
Tire Pressure Setup
Touch to set up the Trailer Tire
Pressure Monitoring System
(TTPMS) for the Trailer Profile. See
“Trailer Tire Pressure Setup” previously in this section for details
on the setup. Also, touch Tire
Pressure Setup if the trailer tires
were rotated or if the tire pressure
sensors in the tires were replaced
for this Trailer Profile. The vehicle
will need to relearn the tire sensors
and their locations.
If TTPMS had been set up
previously, the Select Number of
Sensors screen will appear after
touching Tire Pressure Setup. If the
number of sensors has changed,
select the number and touch Next.
If a new number of sensors is
selected, the Relearn Sensors
pop-up will appear. Touch Cancel to
go back or touch Relearn to
overwrite the current sensors and
begin the relearning process. See
“Trailer Tire Pressure Setup”
previously in this section.
If number of sensors has not
changed, touch Next and the Learn
sensors screen will appear.
On the Learn Sensors screen.
Touch Relearn to overwrite the
current sensors and begin therelearning process. See
“Trailer Tire
Pressure Setup” previously in this
section.
On the Learn Sensors screen, touch
Next to go to the Edit
Recommended Tire Pressure
screen.
On the Edit Recommended Tire
Pressure screen, touch a number on
the keypad to change the
Recommended Tire Pressure for the
trailer ’s tires. This will change the
number at which the vehicle
displays alerts related to trailer tire
pressure. Touch Done to return to
the Trailer Profile view.
Trailer Maintenance
Touch to view a list of maintenance
reminders for the Trailer Profile.
Touch a reminder to view, reset,
delete, or edit it.
Reset Reminder
Touch Maintenance Complete in the
reminder view to reset the reminder.
On the pop-up, touch Reset to reset
the time and mileage values for the