2013 GMC SIERRA service indicator

Black plate (44,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-44 Driving and Operating
{WARNING
Shifting the transfer case to
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). You or someone else
could be seriously injured. Be
sure to set the parking brake
before placing the transfer case in
N (Neutral). SeeParking Brake on
page 9‑51.
N (Neutral): Shift the vehicle's
transfer case to N (Neutral) only
when towing the vehicle. See
Recreational Vehicle Towing on
page 10‑87 orTowing the Vehicle
on page 10‑87 for more information.
If the SERVICE 4 WHEEL DRIVE
message stays on, you should take
the vehicle to your dealer for
service. See “SERVICE 4 WHEEL
DRIVE” underTransmission
Messages on page 5‑44. Shifting Into Two-Wheel
Drive High
Turn the knob to the Two-Wheel
Drive High position. This can be
done at any speed, except when
shifting from Four-Wheel Drive Low.
See
“Shifting Out of Four-Wheel
Drive Low” for more information.
Shifting Into Four-Wheel
Drive Low
When Four-Wheel Drive Low is
engaged, vehicle speed should be
kept below 72 km/h (45 mph).
Extended high-speed operation in
Four-Wheel Drive Low may damage
or shorten the life of the drivetrain.
To shift to the Four-Wheel Drive
Low position, the ignition must be in
ON/RUN and the vehicle must be
stopped or moving less than 5 km/h
(3 mph) with the transmission in
N (Neutral). The preferred method
for shifting into Four-Wheel Drive
Low is to have the vehicle moving
1.6 to 3.2 km/h (1 to 2 mph). Turn the
knob to the Four-Wheel Drive Low
position. You must wait for the Four-Wheel Drive Low indicator light
to stop flashing and remain on
before shifting the transmission
in gear.
Notice:
Shifting the transmission
into gear before the requested
mode indicator light has stopped
flashing could damage the
transfer case. To help avoid
damaging the vehicle, always wait
for the mode indicator lights to
stop flashing before shifting the
transmission into gear.
It is typical for the vehicle to exhibit
significant engagement noise and
bump when shifting between
Four-Wheel Drive Low and
Four-Wheel Drive High ranges or
from transfer case N (Neutral) with
the engine running.
If the knob is turned to the
Four-Wheel Drive Low position
when the vehicle is in gear and/or
moving more than 5 km/h (3 mph),
the Four-Wheel Drive Low indicator
light will flash for 30 seconds and
not complete the shift. After

Black plate (47,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-47
You can choose among five driving
settings:
Indicator lights in the dial show
which setting you are in. The
indicator lights will come on briefly
when you turn on the ignition and
one will stay on. If the lights do not
come on, you should take the
vehicle to your dealer for service.
An indicator light will flash while
shifting the transfer case. It will
remain illuminated when the shift is
complete. If for some reason the
transfer case cannot make a
requested shift, it will return to the
last chosen setting.
2
m(Two-Wheel Drive High):This
setting is used for driving in most
street and highway situations. The
front axle is not engaged in
Two-Wheel Drive. This setting also
provides the best fuel economy.
AUTO (Automatic Four-Wheel
Drive): This setting is ideal for use
when road surface traction
conditions are variable. When
driving the vehicle in AUTO, the front axle is engaged, but the
vehicle's power is sent only to the
front and rear wheels automatically
based on driving conditions. Driving
in this mode results in slightly lower
fuel economy than Two-Wheel
Drive High.
4
m(Four-Wheel Drive High):
Use
the Four-Wheel Drive High position
when extra traction is needed, such
as on snowy or icy roads or in most
off-road situations. This setting also
engages the front axle to help drive
the vehicle. This is the best setting
to use when plowing snow.
4
n(Four-Wheel Drive Low): This
setting also engages the front axle
and delivers extra torque. You may
never need this setting. It sends
maximum power to all four wheels.
You might choose Four-Wheel Drive
Low if you are driving off-road in
deep sand, deep mud, deep snow,
and while climbing or descending
steep hills. If the vehicle has StabiliTrak
®,
shifting into Four-Wheel Drive Low
will turn Traction Control and
StabiliTrak off. See StabiliTrak
®
System on page 9‑53.
{WARNING
Shifting the transfer case to
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). You or someone else
could be seriously injured. Be
sure to set the parking brake
before placing the transfer case in
N (Neutral). SeeParking Brake on
page 9‑51.
N (Neutral): Shift the vehicle's
transfer case to N (Neutral) only
when towing the vehicle. See
Recreational Vehicle Towing on
page 10‑87 orTowing the Vehicle
on page 10‑87 for more information.

Black plate (48,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-48 Driving and Operating
If the SERVICE 4 WHEEL DRIVE
message stays on, you should take
the vehicle to your dealer for
service. See“SERVICE 4 WHEEL
DRIVE” underTransmission
Messages on page 5‑44.
Shifting Into Four-Wheel Drive
High or AUTO (Automatic
Four-Wheel Drive)
Turn the knob to the Four-Wheel
Drive High or AUTO position. This
can be done at any speed, except
when shifting from Four-Wheel
Drive Low. The indicator light will
flash while shifting. It will remain on
when the shift is completed.
Shifting Into Two-Wheel
Drive High
Turn the knob to the Two-Wheel
Drive High position. This can be
done at any speed, except when
shifting from Four-Wheel Drive Low.
The indicator light will flash while
shifting. It will remain on when the
shift is completed. Shifting Into Four-Wheel
Drive Low
When Four-Wheel Drive Low is
engaged, vehicle speed should be
kept below 72 km/h (45 mph).
Extended high-speed operation in
Four-Wheel Drive Low may damage
or shorten the life of the drivetrain.
To shift to the Four-Wheel Drive
Low position, the ignition must be in
ON/RUN and the vehicle must be
stopped or moving less than 5 km/h
(3 mph) with the transmission in
N (Neutral). The preferred method
for shifting into Four-Wheel Drive
Low is to have the vehicle moving
1.6 to 3.2 km/h (1 to 2 mph). Turn the
knob to the Four-Wheel Drive Low
position. You must wait for the
Four-Wheel Drive Low indicator light
to stop flashing and remain on
before shifting the transmission
into gear.
Notice:
Shifting the transmission
into gear before the requested
mode indicator light has stopped
flashing could damage the transfer case. To help avoid
damaging the vehicle, always wait
for the mode indicator lights to
stop flashing before shifting the
transmission into gear.
It is typical for the vehicle to exhibit
significant engagement noise and
bump when shifting between
Four-Wheel Drive Low and
Four-Wheel Drive High ranges or
from N (Neutral) with the engine
running.
If the knob is turned to the
Four-Wheel Drive Low position
when the vehicle is in gear and/or
moving more than 5 km/h (3 mph),
the Four-Wheel Drive Low indicator
light will flash for 30 seconds and
not complete the shift. After
30 seconds the transfer case will
shift to Four-Wheel Drive
High mode. With the vehicle moving
less than 5 km/h (3 mph), and the
transmission in N (Neutral), attempt
the shift again.

Black plate (66,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-66 Driving and Operating
Recommended Fuel
For all vehicles except those with
the 6.2L V8 engine (VIN Code 2),
use regular unleaded gasoline with
a posted octane rating of 87 or
higher. If the octane rating is less
than 87, an audible knocking noise,
commonly referred to as spark
knock, might be heard when driving.
If this occurs, use a gasoline rated
at 87 octane or higher as soon as
possible. If heavy knocking is heard
when using gasoline rated at
87 octane or higher, the engine
needs service.
If the vehicle has the 6.2L V8 engine
(VIN Code 2), use premium
unleaded gasoline with a posted
octane rating of 91 or higher. You
can also use regular unleaded
gasoline rated at 87 octane or
higher, but the vehicle's acceleration
could be slightly reduced, and a
slight audible knocking noise,
commonly referred to as spark
knock, might be heard. If the octane
is less than 87, you might notice aheavy knocking noise when you
drive. If this occurs, use a gasoline
rated at 87 octane or higher as soon
as possible. Otherwise, you could
damage the engine. If heavy
knocking is heard when using
gasoline rated at 87 octane or
higher, the engine needs service.
Gasoline Specifications
At a minimum, gasoline should meet
ASTM specification D 4814. Some
gasolines contain an
octane-enhancing additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). We recommend
against the use of gasolines
containing MMT. See
Fuel Additives
on page 9‑67.
California Fuel
Requirements
If the vehicle is certified to meet
California Emissions Standards, it is
designed to operate on fuels that
meet California specifications. See
the underhood emission control label. If this fuel is not available in
states adopting California Emissions
Standards, the vehicle will operate
satisfactorily on fuels meeting
federal specifications, but emission
control system performance might
be affected. The malfunction
indicator lamp could turn on and the
vehicle might fail a smog‐check test.
See
Malfunction Indicator Lamp on
page 5‑21. If this occurs, return to
your authorized dealer for diagnosis.
If it is determined that the condition
is caused by the type of fuel used,
repairs might not be covered by the
vehicle warranty.
Fuels in Foreign
Countries
Never use leaded gasoline or any
other fuel not recommended in the
previous text on fuel. Costly repairs
caused by use of improper fuel
would not be covered by the vehicle
warranty.

Black plate (67,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
Driving and Operating 9-67
To check the fuel availability, ask an
auto club, or contact a major oil
company that does business in the
country where you will be driving.
Fuel Additives
To provide cleaner air, all gasolines
in the United States are now
required to contain additives that
help prevent engine and fuel system
deposits from forming, allowing the
emission control system to work
properly. In most cases, nothing
should have to be added to the fuel.
However, some gasolines contain
only the minimum amount of
additive required to meet U.S.
Environmental Protection Agency
regulations. To help keep fuel
injectors and intake valves clean
and avoid problems due to dirty
injectors or valves, look for gasoline
that is advertised as TOP TIER
Detergent Gasoline. Look for the
TOP TIER label on the fuel pump to
ensure gasoline meets enhanced
detergency standards developed by
the auto companies. A list ofmarketers providing TOP TIER
Detergent Gasoline can be found at
www.toptiergas.com.
For customers who do not use TOP
TIER Detergent Gasoline regularly,
one bottle of GM Fuel System
Treatment PLUS, added to the fuel
tank at every engine oil change, can
help clean deposits from fuel
injectors and intake valves. GM Fuel
System Treatment PLUS is the only
gasoline additive recommended by
General Motors. It is available at
your dealer.
Gasolines containing oxygenates,
such as ethers and ethanol, and
reformulated gasolines might be
available in your area. We
recommend that you use these
gasolines, if they comply with the
specifications described earlier.
However, E85 (85% ethanol) and
other fuels containing more than
15% ethanol must not be used in
vehicles that were not designed for
those fuels.
Notice:
This vehicle was not
designed for fuel that contains
methanol. 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.
Some gasolines that are not
reformulated for low emissions can
contain an octane-enhancing
additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT); ask the attendant
where you buy gasoline whether the
fuel contains MMT. We recommend
against the use of such gasolines.
Fuels containing MMT can reduce
spark plug life and affect emission
control system performance. The
malfunction indicator lamp might
turn on. If this occurs, return to your
dealer for service.

Black plate (68,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
9-68 Driving and Operating
Fuel E85 (85% Ethanol)
Vehicles that have a yellow fuel cap
can use either unleaded gasoline or
ethanol fuel containing up to 85%
ethanol (E85). For all other vehicles,
use only the unleaded gasoline
described underRecommended
Fuel on page 9‑66.
We encourage the use of E85 in
vehicles that are designed to use it.
The ethanol in E85 is a “renewable”
fuel, meaning it is made from
renewable sources such as corn
and other crops.
Many service stations will not have
an 85% ethanol fuel (E85) pump
available. The U.S. Department of
Energy has an alternative fuels
website (www.afdc.energy.gov/afdc/
locator/stations/) that can help you
find E85 fuel. Those stations that do
have E85 should have a label
indicating ethanol content. Do not
use the fuel if the ethanol content is
greater than 85%. At a minimum, E85 should meet
ASTM Specification D 5798 or
CGSB Specification 3.512. Filling
the tank with fuel mixtures that do
not meet ASTM or CGSB
specifications can affect driveability
and could cause the malfunction
indicator lamp to come on. As the
outside temperature approaches
freezing, ethanol fuel distributors
should supply winter grade ethanol,
the same as with unleaded
gasoline.
It is best not to alternate repeatedly
between gasoline and E85. If you
do switch fuels, it is recommended
that you add as much fuel as
possible
—do not add less than
11 L (3 gal) when refueling. You
should drive the vehicle immediately
after refueling for at least 11 km
(7 mi) to allow the vehicle to adapt
to the change in ethanol
concentration.
E85 has less energy per liter
(gallon) than gasoline, so you will
need to refill the fuel tank more often when using E85 than when
you are using gasoline. See
Filling
the Tank on page 9‑68.
Notice: Some additives are not
compatible with E85 fuel and can
harm the vehicle's fuel system.
Do not add anything to E85.
Damage caused by additives
would not be covered by the
vehicle warranty.
Notice: This vehicle was not
designed for fuel that contains
methanol. 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.
Filling the Tank
If the vehicle has a diesel engine,
see the Duramax diesel supplement
for more information.

Black plate (20,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-20 Vehicle Care
3. Fill the coolant surge tank withthe proper mixture to the FULL
COLD mark.
4. With the coolant surge tank pressure cap off, start the
engine and let it run until the
engine coolant temperature
gauge indicates approximately
90°C (195°F).
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper mixture to the coolant surge tank
until the level reaches the FULL
COLD mark.
5. Replace the pressure cap tightly.
6. Verify coolant level after the engine is shut off and the
coolant is cold. If necessary,
repeat coolant fill procedure
Steps 1 through 6.
Notice: If the pressure cap is not
tightly installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured.
Engine Overheating
If the vehicle has the Duramax®
Diesel engine, see the Duramax
Diesel Supplement for more
information.
The vehicle has several indicators
to warn of engine overheating.
There is a coolant temperature
gauge on the vehicle's instrument
panel. See Engine Coolant
Temperature Gauge on page 5‑15. In addition, there are ENGINE
OVERHEATED STOP ENGINE,
ENGINE OVERHEATED IDLE
ENGINE, and ENGINE POWER IS
REDUCED messages in the Driver
Information Center (DIC) on the
instrument panel. See
Engine
Cooling System Messages on
page 5‑39 andEngine Power
Messages on page 5‑40.
If the decision is made not to lift the
hood when this warning appears,
get service help right away. See
Roadside Assistance Program
(Mexico) on page 13‑7 orRoadside
Assistance Program (U.S. and
Canada) on page 13‑11.
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.
Then check to see if the engine
cooling fans are running. If the
engine is overheating, both fans
should be running. If they are not,
do not continue to run the engine
and have the vehicle serviced.

Black plate (24,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-24 Vehicle Care
Adding Washer Fluid
The vehicle has a low washer fluid
message on the DIC that comes on
when the washer fluid is low. The
message is displayed for
15 seconds at the start of each
ignition cycle. When the WASHER
FLUID LOW ADD FLUID message
displays, washer fluid will need to
be added to the windshield washer
fluid reservoir.
Open the cap with the washer
symbol on it. Add washer fluid until
the tank is full. SeeEngine
Compartment Overview on
page 10‑5 for reservoir location. Notice
.When using concentrated
washer fluid, follow the
manufacturer instructions for
adding water.
.Do not mix water with
ready-to-use washer fluid.
Water can cause the solution
to freeze and damage the
washer fluid tank and other
parts of the washer system.
.Fill the washer fluid tank only
three-quarters full when it is
very cold. This allows for
fluid expansion if freezing
occurs, which could damage
the tank if it is
completely full.
.Do not use engine coolant
(antifreeze) in the windshield
washer. It can damage the
windshield washer system
and paint.
Brakes
This vehicle has front disc brakes
and could have rear drum brakes or
rear disc brakes.
Disc brake pads have built-in wear
indicators that make a high-pitched
warning sound when the brake pads
are worn and new pads are needed.
The sound can come and go or be
heard all the time the vehicle is
moving, except when applying the
brake pedal firmly.
{WARNING
The brake wear warning sound
means that soon the brakes will
not work well. That could lead to
a crash. When the brake wear
warning sound is heard, have the
vehicle serviced.
Notice: Continuing to drive with
worn-out brake pads could result
in costly brake repair.