add fuel GMC SIERRA 2020 Owner's Manual

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
78 Seats and Restraints
The vehicle has a feature that may
automatically unlock the doors, turn
on the interior lamps and hazard
warning flashers, and shut off the
fuel system after the airbags inflate.
The feature may also activate,
without airbag inflation, after an
event that exceeds a predetermined
threshold. After turning the ignition
off and then on again, the fuel
system will return to normal
operation; the doors can be locked,
the interior lamps can be turned off,
and the hazard warning flashers can
be turned off using the controls for
those features. If any of these
systems are damaged in the crash
they may not operate as normal.
{Warning
A crash severe enough to inflate
the airbags may have also
damaged important functions in
the vehicle, such as the fuel
system, brake and steering
systems, etc. Even if the vehicle
appears to be drivable after a(Continued)
Warning (Continued)
moderate crash, there may be
concealed damage that could
make it difficult to safely operate
the vehicle.
Use caution if you should attempt
to restart the engine after a crash
has occurred.
In many crashes severe enough to
inflate the airbag, windshields are
broken by vehicle deformation.
Additional windshield breakage may
also occur from the front outboard
passenger airbag.
. Airbags are designed to inflate
only once. After an airbag
inflates, you will need some new
parts for the airbag system.
If you do not get them, the
airbag system will not be there
to help protect you in another
crash. A new system will include
airbag modules and possibly
other parts. The service manual
for the vehicle covers the need
to replace other parts. .
The vehicle has a crash sensing
and diagnostic module which
records information after a
crash. See Vehicle Data
Recording and Privacy 0474
and
Event Data Recorders 0475.
. Let only qualified technicians
work on the airbag systems.
Improper service can mean that
an airbag system will not work
properly. See your dealer for
service.
Passenger Sensing
System
The vehicle has a passenger
sensing system for the front
outboard passenger position. The
passenger airbag status indicator
will light on the overhead console
when the vehicle is started.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Instruments and Controls 139
Caution
Modifications to the engine,
transmission, exhaust, intake,
or fuel system, or the use of
replacement tires that do not
meet the original tire
specifications, can cause this light
to come on. This could lead to
costly repairs not covered by the
vehicle warranty. This could also
affect the vehicle’s ability to pass
an Emissions Inspection/
Maintenance test. See
Accessories and Modifications
0329.
If the light is flashing : A
malfunction has been detected that
could damage the emission control
system and increase vehicle
emissions. Diagnosis and service
may be required.
To help prevent damage, reduce
vehicle speed and avoid hard
accelerations and uphill grades. If towing a trailer, reduce the
amount of cargo being hauled as
soon as possible.
If the light continues to flash, find a
safe place to park. Turn the vehicle
off and wait at least 10 seconds
before restarting the engine. If the
light is still flashing, follow the
previous guidelines and see your
dealer for service as soon as
possible.
If the light is on steady :
A
malfunction has been detected.
Diagnosis and service may be
required.
Check the following:
. If fuel has been added to the
vehicle using the capless funnel
adapter, make sure that it has
been removed. See “Filling the
Tank with a Portable Gas Can”
under Filling the Tank (Pickup
Model) 0283 or
Filling the Tank (Chassis Cab
Model) 0285. The diagnostic
system can detect if the adapter
has been left installed in the
vehicle, allowing fuel to evaporate into the atmosphere.
A few driving trips with the
adapter removed may turn off
the light.
. Poor fuel quality can cause
inefficient engine operation and
poor driveability, which may go
away once the engine is warmed
up. If this occurs, change the
fuel brand. It may require at
least one full tank of the proper
fuel to turn the light off. See
Recommended Fuel (Except
6.2L V8 Engine) 0280 or
Recommended Fuel (6.2L
V8 Engine) 0281.
If the light remains on, see your
dealer.
Emissions Inspection and
Maintenance Programs
If the vehicle requires an Emissions
Inspection/Maintenance test, the
test equipment will likely connect to
the vehicle's Data Link
Connector (DLC).

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
146 Instruments and Controls
For vehicles with the Tire Pressure
Monitor System (TPMS), this light
comes on briefly when the engine is
started. It provides information
about tire pressures and the TPMS.
When the Light Is On Steady
This indicates that one or more of
the tires are significantly
underinflated.
A Driver Information Center (DIC)
tire pressure message may also
display. Stop as soon as possible,
and inflate the tires to the pressure
value shown on the Tire and
Loading Information label. SeeTire
Pressure 0387.
When the Light Flashes First and
Then Is On Steady
If the light flashes for about a minute
and then stays on, there may be a
problem with the TPMS. If the
problem is not corrected, the light
will come on at every ignition cycle.
See Tire Pressure Monitor
Operation 0390.Engine Oil Pressure Light
(Uplevel Cluster)
Caution
Lack of proper engine oil
maintenance can damage the
engine. Driving with the engine oil
low can also damage the engine.
The repairs would not be covered
by the vehicle warranty. Check
the oil level as soon as possible.
Add oil if required, but if the oil
level is within the operating range
and the oil pressure is still low,
have the vehicle serviced. Always
follow the maintenance schedule
for changing engine oil.
This light should come on briefly as
the engine is started. If it does not
come on, have the vehicle serviced
by your dealer.
If the light comes on and stays on, it
means that oil is not flowing through
the engine properly. The vehicle
could be low on oil and might have
some other system problem. See
your dealer.
Low Fuel Warning Light
This light is near the fuel gauge and
comes on briefly when the ignition is
turned on as a check to show it is
working.
It also comes on when the fuel tank
is low on fuel. The light turns off
when fuel is added. If it does not,
have the vehicle serviced.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Instruments and Controls 149
recent driving history and the
amount of fuel remaining in the fuel
tank. Fuel range cannot be reset.
Tire Pressure
Turn the trip odometer reset stem
until a vehicle with the approximate
pressures of all four tires displays.
Tire pressure is displayed in either
kilopascal (kPa) or in pounds per
square inch (psi).
SeeTire Pressure Monitor System
0 389 and
Tire Pressure Monitor Operation
0 390.
Remaining Oil Life
Turn the trip odometer reset stem
until REMAINING OIL LIFE
displays. An estimate of the oil's
remaining useful life is shown.
REMAINING OIL LIFE 99% means
99% of the current oil life remains.
When the remaining oil life is low,
the CHANGE ENGINE OIL SOON
message will appear on the display.
The oil should be changed as soon
as possible. See Engine Oil0339.
In addition to the engine oil life system monitoring the oil life,
additional maintenance is
recommended. See
Maintenance
Schedule 0442.
The Oil Life display must be reset
after each oil change. It will not
reset itself. Do not reset the Oil Life
display at any time other than when
the oil has just been changed.
It cannot be reset accurately until
the next oil change. To reset the
engine oil life system, see Engine
Oil Life System 0341.
Air Filter Life
Turn the trip odometer reset stem
until AIR FILTER LIFE displays.
This displays an estimate of the
engine air filter ’s remaining useful
life and the state of the system.
Engine Air Filter Life 95% means
95% of the current air filter life
remains. Messages will display
based on the engine air filter life and
the state of the system.
When the REPLACE AT NEXT OIL
CHANGE message displays, the
engine air filter should be replaced
at the time of the next oil change. When the REPLACE SOON
message displays, the engine air
filter should be replaced at the
earliest convenience.
The Air Filter Life display must be
reset after the engine air filter
replacement. To reset, see
Engine
Air Filter Life System 0343.
Brake Pad Life
This displays an estimate of the
remaining life of the front and rear
brake pads. Messages will display
based on brake pad wear and the
state of the system. Reset the Brake
Pad Life display after replacing the
brake pads. See Brake Pad Life
System 0356.
Driver Information Center
(DIC) (Midlevel and
Uplevel)
The DIC displays are shown in the
center of the instrument cluster in
the Info app. See Instrument Cluster
0 127. The displays show the status
of many vehicle systems.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Instruments and Controls 151
economy that the vehicle has right
now, and will change as driving
conditions change.
Press the thumbwheel while this
display is active to reset the trip
odometer and the average fuel
economy.
Fuel Range :Shows the
approximate distance the vehicle
can be driven without refueling.
LOW will be displayed when the
vehicle is low on fuel. The fuel
range estimate is based on an
average of the vehicle's fuel
economy over recent driving history
and the amount of fuel remaining in
the fuel tank.
Timer : This display can be used as
a timer. To start the timer, press the
thumbwheel while this display is
active. The display will show the
amount of time that has passed
since the timer was last reset. To
stop the timer, press the
thumbwheel briefly while this display
is active and the timer is running.
Press the thumbwheel while this
display is active to reset the timer. Oil Life :
Shows an estimate of the
oil's remaining useful life.
If REMAINING OIL LIFE 99% is
displayed, that means 99% of the
current oil life remains.
When the remaining oil life is low,
the CHANGE ENGINE OIL SOON
message will appear on the display.
The oil should be changed as soon
as possible. See Engine Oil0339.
In addition to the engine oil life
system monitoring the oil life,
additional maintenance is
recommended. See Maintenance
Schedule 0442.
The Oil Life display must be reset
after each oil change. It will not
reset itself. Do not reset the Oil Life
display at any time other than when
the oil has just been changed.
It cannot be reset accurately until
the next oil change. To reset the
engine oil life system, press the
thumbwheel while the Oil Life
display is active. See Engine Oil
Life System 0341.
Tire Pressure : Shows the
approximate pressures of all four
tires. Tire pressure is displayed in either kilopascal (kPa) or in pounds
per square inch (psi). If the pressure
is low, the value for that tire is
shown in amber. See
Tire Pressure
Monitor System 0389 and
Tire Pressure Monitor Operation
0 390.
Air Filter Life : Shows an estimate
of the engine air filter ’s remaining
useful life and the state of the
system. Engine Air Filter Life 95%
means 95% of the current air filter
life remains. Messages will display
based on the engine air filter life and
the state of the system. When the
REPLACE AT NEXT OIL CHANGE
message displays, the engine air
filter should be replaced at the time
of the next oil change. When the
REPLACE SOON message
displays, the engine air filter should
be replaced at the earliest
convenience.
The Air Filter Life display must be
reset after the engine air filter
replacement. To reset, see Engine
Air Filter Life System 0343.

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 203
Example 3
1. Vehicle Capacity Weight forExample 3 = 453 kg
(1,000 lb)
2. Subtract Occupant Weight @ 91 kg (200 lb) × 5 =
453 kg (1,000 lb)
3. Available Cargo Weight = 0 kg (0 lb)
Refer to the Tire and Loading
Information label for specific
information about the vehicle's
capacity weight and seating
positions. The combined weight of the driver, passengers, and
cargo should never exceed the
vehicle's capacity weight.
Certification/Tire Label
A vehicle-specific Certification/
Tire label is label is attached to
the center pillar (B-pillar). The
label may show the size of the
vehicle's original tires and the
inflation pressures needed to
obtain the gross weight capacity
of the vehicle. This is called
Gross Vehicle Weight
Rating (GVWR). The GVWRincludes the weight of the
vehicle, all occupants, fuel, and
cargo.
The Certification/Tire label also
may show the maximum weights
for the front and rear axles,
called Gross Axle Weight
Rating (GAWR). To determine
the actual loads on the front and
rear axles, weigh the vehicle at
a weigh station. Your dealer can
help with this. Be sure to spread
the load equally on both sides of
the centerline.
The Certification/Tire label also
contains important information
about the Front Axle Reserve
Capacity. See
Adding a Snow
Plow or Similar Equipment
0 323.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 229
automatically based on driving
conditions. This setting provides
slightly lower fuel economy than 2
m.
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.
4
n(Four-Wheel Drive Low) : This
setting engages the front axle and
delivers extra torque. Choose 4
n
when driving off-road in deep sand,
deep mud, or deep snow, and while
climbing or descending steep hills.
While driving in 4
n, keep vehicle
speed below 72 km/h (45 mph).
Shifting into 4
nwill turn Traction
Control and StabiliTrak/ESC off.
See Traction Control/Electronic
Stability Control 0235.
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
to indicate that the 4x4 transfer case
has been requested to shift to the
new desired state.
Once the 4x4 shift has completed,
the DIC message disappears, the
4x4 graphic stops flashing, and the
current setting is indicated.
When a shift to 2
mis completed
successfully while in P (Park), the
parking brake will engage. To
resume driving, shift the
transmission to the desired gear
and manually release the parking
brake or press the accelerator pedal
to begin driving. See Electric
Parking Brake 0233.
If equipped, use 4
n, AUTO, or 4mto
provide additional traction when
parking on a steep grade with poor
traction such as ice, snow, mud,
or gravel. Shifting Into 4
n
1. The ignition must be on and
the vehicle must be stopped or
moving less than 5 km/h
(3 mph) with the transmission
in N (Neutral). It is best for the
vehicle to be moving
1.6 to 3.2 km/h (1 to 2 mph).
2. Press 4
n. 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 to indicate that the 4x4
transfer case has been
requested to shift to the new
desired state.
Once the 4x4 shift has
completed, the DIC message
disappears, the 4x4 graphic
stops flashing and the current
setting is indicated.
If vehicle speed is higher when shift
request occurs, a DIC message
displays. Reduce vehicle speed.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
282 Driving and Operating
Fuel Additives
TOP TIER Detergent Gasoline is
highly recommended for use with
your vehicle. If your country does
not have TOP TIER Detergent
Gasoline, add ACDelco Fuel
System Treatment Plus−Gasoline to
the vehicle’s gasoline fuel tank at
every oil change or 15 000 km
(9,000 mi), whichever occurs first.
TOP TIER Detergent Gasoline and
ACDelco Fuel System Treatment
Plus−Gasoline will help keep your
vehicle’s engine fuel deposit free
and performing optimally.
E85 or FlexFuel
Vehicles with a yellow fuel sticker
on the fuel door can use either
unleaded gasoline or fuel containing
up to 85% ethanol (E85). All other
vehicles should use only the
unleaded gasoline as described in
Recommended Fuel (Except 6.2L
V8 Engine) 0280 or
Recommended Fuel (6.2L
V8 Engine) 0281. The use of E85 or FlexFuel is
encouraged when the vehicle is
designed to use it. E85 or FlexFuel
is made from renewable sources.
To help locate fuel stations that
carry E85 or FlexFuel, the U.S.
Department of Energy has an
alternative fuel website. See
www.afdc.energy.gov/afdc/locator/
stations.
E85 or FlexFuel should meet ASTM
Specification D 5798 or CAN/
CGSB–3.512 in Canada. Do not use
the fuel if the ethanol content is
greater than 85%. Fuel mixtures that
do not meet ASTM or CGSB
specifications can affect driveability
and could cause the malfunction
indicator lamp to come on.
The starting characteristics of E85
or FlexFuel make it unsuitable for
use when temperatures fall below
−18 °C (0 °F). Use gasoline or add
gasoline to the E85 or FlexFuel.
Because E85 or FlexFuel has less
energy per liter (gallon) than
gasoline, the vehicle will need to be refilled more often. See
Filling the
Tank (Pickup Model) 0283 or
Filling the Tank (Chassis Cab
Model) 0285.
The only GM approved aftermarket
additive is ACDelco Fuel System
Treatment Plus-FlexFuel. Follow the
instructions on the bottle for proper
use. This product is available at
your GM dealer.
Caution
Some additives are not
compatible with E85 or FlexFuel
and can harm the vehicle's fuel
system. Use only additives
approved by GM for E85 or
FlexFuel vehicles. Damage
caused by unapproved additives
would not be covered by the
vehicle warranty.

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.