2020 GMC SIERRA diesel fuel system

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
148 Instruments and Controls
For vehicles with cruise control, the
cruise control light is white when the
cruise control is on and ready, and
turns green when the cruise control
is set and active.
The light turns off when the cruise
control is turned off. SeeCruise
Control 0243.
Door Ajar Light
This light comes on when a door is
open or not securely latched. Before
driving, check that all doors are
properly closed.
Information Displays
Driver Information Center
(DIC) (Base Level)
The DIC displays are shown in the
center of the instrument cluster. The
displays show the status of many
vehicle systems. The trip odometer
reset stem in the instrument cluster
is used to access the DIC menu
items.
If the vehicle has a diesel engine,
see the Duramax diesel supplement
for more information.
DIC Menu Items
Turn the trip odometer reset stem to
scroll through the following menu
items:
.
Digital Speedometer
. Trip 1/2
. Fuel Range
. Tire Pressure
. Remaining Oil Life
. Air Filter Life .
Brake Pad Life
Digital Speedometer
The speedometer shows how fast
the vehicle is moving in either
kilometers per hour (km/h) or miles
per hour (mph). The speedometer
cannot be reset.
Trip 1 or 2 and Average Fuel
Economy
Turn the trip odometer reset stem
until TRIP 1 or TRIP 2 displays. The
current distance traveled, in either
kilometers (km) or miles (mi), since
the last reset for the trip odometer is
shown, as well as the average fuel
economy. The trip odometer and the
average fuel economy can be reset
by pressing and holding the trip
odometer reset stem.
Fuel Range
This display shows the approximate
distance the vehicle can be driven
without refueling. The fuel range
estimate is based on an average of
the vehicle's fuel economy over

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
280 Driving and Operating
system does not need service.
Clean the outside of the windshield
behind the rearview mirror.
LKA assistance and/or LDW alerts
may occur due to tar marks,
shadows, cracks in the road,
temporary or construction lane
markings, or other road
imperfections. This is normal system
operation; the vehicle does not need
service. Turn LKA off if these
conditions continue.Fuel
Top Tier Fuel
GM recommends the use of TOP
TIER Detergent Gasoline to keep
the engine clean, reduce engine
deposits, and maintain optimal
vehicle performance. Look for the
TOP TIER Logo or see
www.toptiergas.com for a list of TOP
TIER Detergent Gasoline marketers
and applicable countries.
Recommended Fuel
(Except 6.2L V8 Engine)
For diesel engine vehicles, see
“Fuel for Diesel Engines”in the
Duramax diesel supplement.
If the vehicle has a yellow fuel cap
or a yellow sticker on the fuel door,
E85 or FlexFuel can be used. If the
vehicle does not have a yellow fuel
cap or yellow sticker, do not use
gasoline with ethanol levels greater
than 15% by volume. See E85 or
FlexFuel 0282.
Use regular unleaded gasoline
meeting ASTM specification D4814
with a posted octane rating of 87 —
(R+M)/2 —or higher. Do not use
gasoline with a posted octane rating
of less than 87, as this may cause
engine knock and will lower fuel
economy.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 283
Caution
Do not use fuel containing
methanol. It can corrode metal
parts in the fuel system and also
damage plastic and rubber parts.
That damage would not be
covered under the vehicle
warranty.
To help keep the engine running
efficiently, fill the tank with gasoline,
up to E15, after filling the tank with
E85 one or two times.
Filling the Tank (Pickup
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. See Fuel 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.
. 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.
(Continued)
Warning (Continued)
.Before touching the fill
nozzle, touch a metallic
object to discharge static
electricity from your body.
. Fuel can spray out if the fill
nozzle is inserted too
quickly. This spray can
happen if the tank is nearly
full, and is more likely in hot
weather. Insert the fill nozzle
slowly and wait for any hiss
noise to stop before
beginning to flow fuel.

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
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 - 4/10/19
Vehicle Care 353
vehicle to be driven to a safe place
in an emergency. Driving extended
distances and/or towing a trailer in
the overheat protection mode
should be avoided.
Caution
After driving in the overheated
engine protection operating
mode, the engine oil will be
severely degraded. Any repairs
performed before the engine is
cool may cause engine damage.
Allow the engine to cool before
attempting any repair. Repair the
cause of coolant loss, change the
oil, and reset the oil life system.
SeeEngine Oil 0339.
Engine Fan
If the vehicle has the Duramax
diesel engine, see the Duramax
diesel supplement.
All Engines Except 6.6L
V8 Engine (L8T)
The vehicle has electric cooling
fan(s). The fans may be heard
spinning at low speed during most
everyday driving. The fans may turn
off if no cooling is required. Under
heavy vehicle loading, trailer towing,
high outside temperatures,
or operation of the air conditioning
system, the fans may change to
high speed and an increase in fan
noise may be heard. This is normal
and indicates that the cooling
system is functioning properly. The
fans will change to low speed when
additional cooling is no longer
required.
The electric engine cooling fans
may run after the engine has been
turned off. This is normal and no
service is required.
6.6L V8 Engine (L8T) Only
The vehicle has a clutched engine
cooling fan. When the clutch is
engaged, the fan spins faster to
provide more air to cool the engine.
In most everyday driving conditions,
the fan is spinning slower and the
clutch is not fully engaged. This
improves fuel economy and reduces
fan noise. Under heavy vehicle
loading, trailer towing, and/or high
outside temperatures, the fan speed
increases as the clutch more fully
engages, so an increase in fan
noise may be heard. This is normal
and should not be mistaken as the
transmission slipping or making
extra shifts. It is merely the cooling
system functioning properly. The fan
will slow down when additional
cooling is not required and the
clutch partially disengages.
This fan noise may be heard when
starting the engine. It will go away
as the fan clutch partially
disengages.