
Black plate (21,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
In Brief 1-21
The low tire pressure warning light
alerts to a significant loss in
pressure of one of the vehicle's
tires. If the warning light comes on,
stop as soon as possible and inflate
the tires to the recommended
pressure shown on the Tire and
Loading Information label. See
Vehicle Load Limits on page 9-15.
The warning light will remain on until
the tire pressure is corrected.
The low tire pressure warning light
may come on in cool weather when
the vehicle is first started, and then
turn off as the vehicle is driven. This
may be an early indicator that the
tire pressures are getting low and
the tires need to be inflated to the
proper pressure.
The TPMS does not replace normal
monthly tire maintenance. Maintain
the correct tire pressures.
SeeTire Pressure Monitor System
on page 10-61.Engine Oil Life System
The engine oil life system calculates
engine oil life based on vehicle use
and displays a DIC message when
it is necessary to change the engine
oil and filter. The oil life system
should be reset to 100% only
following an oil change.
Resetting the Oil Life System
1. Display OIL LIFE REMAINING
on the DIC. See Driver
Information Center (DIC) on
page 5-27.
2. Press and hold
Vfor several
seconds. The oil life will change
to 100%.
The oil life system can also be reset
as follows:
1. Turn the ignition to ON/RUN with the engine off.
2. Fully press the accelerator pedal slowly three times within
five seconds. 3. Display the OIL LIFE
REMAINING on the DIC. If the
display shows 100%, the system
is reset.
See Engine Oil Life System on
page 10-11.
E85 or FlexFuel
Vehicles with a yellow fuel cap can
use either unleaded gasoline or
ethanol fuel containing up to 85%
ethanol (E85). See E85 or FlexFuel
on page 9-65. For all other vehicles,
use only the unleaded gasoline
described under Fuel on page 9-63.
Driving for Better Fuel
Economy
Driving habits can affect fuel
mileage. Here are some driving tips
to get the best fuel economy
possible.
.Avoid fast starts and accelerate
smoothly.
.Brake gradually and avoid
abrupt stops.

Black plate (29,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-29
Fuel Range and Instantaneous
Fuel Economy: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. It also shows if the
Active Fuel Management is active
and in V4 mode, or inactive and in
V8 mode. See Active Fuel
Management
®on page 9-32.
The Instantaneous Fuel Economy
display shows the approximate
current fuel economy in either liters
per 100 kilometers (L/100 km) or
miles per gallon (mpg). This number
reflects only the approximate fuel
economy that the vehicle has right
now and changes frequently as
driving conditions change. Timer and Fuel Used:
This display
can be used as a timer. To start the
timer, press
Vwhile 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
Vbriefly while
this display is active and the timer is
running.
This also shows the number of
liters (L) or gallons (gal) of fuel used
since the last reset of this
menu item.
Press and hold
Vwhile this display
is active to reset the timer and fuel
used. Each of these items can be
reset individually by pressing
p
while this display is active.
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.
See
Engine Oil Messages on
page 5-34. The oil should be
changed as soon as possible. See
Engine Oil on page 10-8. In addition
to the engine oil life system
monitoring the oil life, additional
maintenance is recommended in the
Maintenance Schedule. See
Maintenance Schedule on
page 11-3.
The Oil Life display must be reset
after each oil change. It will not
reset itself. Do not to 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 and
hold
Vfor several seconds while
the Oil Life display is active. See
Engine Oil Life System on
page 10-11.

Black plate (34,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
5-34 Instruments and Controls
Engine Oil Messages
CHANGE ENGINE OIL SOON
This message displays when the
engine oil needs to be changed.
When you change the engine oil, be
sure to reset the CHANGE ENGINE
OIL SOON message. SeeEngine
Oil Life System on page 10-11 for
information on how to reset the
message. See Engine Oil on
page 10-8 andMaintenance
Schedule on page 11-3.
ENGINE OIL LOW ADD OIL
On some vehicles, this message
displays when the engine oil level
may be too low. Check the oil level
before filling to the recommended
level. If the oil is not low and this
message remains on, take the
vehicle to your dealer for service.
See Engine Oil on page 10-8.
ENGINE OIL HOT IDLE
ENGINE
This message displays when the
engine oil becomes hotter than the
normal operating temperature. Stop
and allow the vehicle to idle until it
cools down. See Engine Coolant
Temperature Gauge on page 5-13.
OIL PRESSURE LOW STOP
ENGINE
This message displays if low oil
pressure levels occur. Stop the
vehicle as soon as safely possible
and do not operate it until the cause
of the low oil pressure has been
corrected. Check the oil as soon as
possible and have the vehicle
serviced by your dealer. See Engine
Oil on page 10-8.
Engine Power Messages
ENGINE POWER IS REDUCED
This message displays and a chime
may sound when the cooling system
temperature gets too hot and the engine further enters the engine
coolant protection mode. See
Engine Overheating on page 10-21
for more information.
This message also displays when
the vehicle's engine power is
reduced. Reduced engine power
can affect the vehicle's ability to
accelerate. If this message is on,
but there is no reduction in
performance, proceed to your
destination. The performance may
be reduced the next time the vehicle
is driven. The vehicle may be driven
at a reduced speed while this
message is on, but acceleration and
speed may be reduced. Anytime
this message stays on, the vehicle
should be taken to your dealer for
service as soon as possible.

Black plate (64,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-64 Driving and Operating
{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.
Some gasolines, mainly high octane
racing gasolines, can contain an
octane-enhancing additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). Do not use
gasolines and/or fuel additives with
MMT as they can reduce spark plug
life and affect emission control
system performance. The
malfunction indicator lamp may turn
on. If this occurs, see your dealer
for service.
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 may not pass a smog-check
test. See Malfunction Indicator
Lamp on page 5-18. 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 may not be
covered by the vehicle warranty.
Fuels in Foreign
Countries
If planning to drive in countries
outside the U.S. or Canada, the
proper fuel might be hard to find.
Check regional auto club or fuel
retail brand websites for availability
in the country where driving. Never
use leaded gasoline, fuel containing
methanol, manganese, or any other
fuel not recommended. Costly
repairs caused by use of improper
fuel would not be covered by the
vehicle warranty.
Fuel Additives
To keep fuel systems clean, TOP
TIER Detergent Gasoline is
recommended. See Fuel on
page 9-63.
If TOP TIER Detergent Gasoline is
not available, one bottle of Fuel
System Treatment PLUS added to
the fuel tank at every engine oil
change can help. Fuel System
Treatment PLUS is the only

Black plate (9,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-9
Checking Engine Oil
It is a good idea to check the engine
oil level at each fuel fill. In order to
get an accurate reading, the vehicle
must be on level ground. The
engine oil dipstick handle is a loop.
SeeEngine Compartment Overview
on page 10-5 for the location of the
engine oil dipstick.
If a low oil message displays on the
DIC, it is important to park on level
ground to accurately measure the
oil level on the dipstick. Idling the
vehicle on steep grades for a long
time can influence the level sensing
accuracy.
Obtaining an accurate oil level
reading is essential:
1. If the engine has been running recently, turn off the engine and
allow several minutes for the oil
to drain back into the oil pan.
Checking the oil level too soon
after engine shutoff will not
provide an accurate oil level
reading.{Warning
The engine oil dipstick handle
may be hot; it could burn you.
Use a towel or glove to touch the
dipstick handle.
2. Pull out the dipstick and wipe it with a clean paper towel or cloth,
then push it back in all the way.
Remove it again, keeping the tip
down, and check the level.
When to Add Engine Oil
If the oil is below the cross-hatched
area at the tip of the dipstick, add
1 L (1 qt) of the recommended oil
and then recheck the level. See
“Selecting the Right Engine Oil” in
this section for an explanation of what kind of oil to use. For engine
oil crankcase capacity, see
Capacities and Specifications on
page 12-2.
{Caution
Do not add too much oil. Oil
levels above or below the
acceptable operating range
shown on the dipstick are harmful
to the engine. If you find that you
have an oil level above the
operating range, i.e., the engine
has so much oil that the oil level
gets above the cross-hatched
area that shows the proper
operating range, the engine could
be damaged. You should drain
out the excess oil or limit driving
of the vehicle and seek a service
professional to remove the
excess amount of oil.
See Engine Compartment Overview
on page 10-5 for the location of the
engine oil fill cap.

Black plate (10,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-10 Vehicle Care
Add enough oil to put the level
somewhere in the proper operating
range. Push the dipstick all the way
back in when through.
Selecting the Right Engine Oil
Selecting the right engine oil
depends on both the proper oil
specification and viscosity grade.
SeeRecommended Fluids and
Lubricants on page 11-12.
Specification
Use and ask for licensed engine oils
with the dexos1
®approved
certification mark. Engine oils
meeting the requirements for the
vehicle should have the dexos1
approved certification mark. This
certification mark indicates that the
oil has been approved to the dexos1
specification. See
www.gmdexos.com.
{Caution
Failure to use the recommended
engine oil can result in engine
damage not covered by the
vehicle warranty. Check with your
dealer or service provider on
whether the oil is approved to the
dexos1 specification.
Viscosity Grade
Use SAE 0W-20 viscosity grade for
the 5.3L and 6.2L V8 engines. Use
SAE 5W-30 viscosity grade for the
6.0L V8 engine.
Cold Temperature Operation: In an
area of extreme cold, where the
temperature falls below −29°C
(−20°F), an SAE 0W-30 oil may be
used in the 6.0L engine. An oil of this viscosity grade will provide
easier cold starting for the engine at
extremely low temperatures.
When selecting an oil of the
appropriate viscosity grade, always
select an oil of the correct
specification. See
“Specification”
earlier in this section.Engine Oil Additives/Engine
Oil Flushes
Do not add anything to the oil. The
recommended oils with the dexos
specification and displaying the
dexos certification mark are all that
is needed for good performance and
engine protection.
Engine oil system flushes are not
recommended and could cause
engine damage not covered by the
vehicle warranty.
What to Do with Used Oil
Used engine oil contains certain
elements that can be unhealthy for
your skin and could even cause
cancer. Do not let used oil stay on

Black plate (12,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-12 Vehicle Care
The oil life system can also be reset
as follows:
1. Turn the ignition to ON/RUN withthe engine off.
2. Fully press the accelerator pedal slowly three times within
five seconds.
3. Display the OIL LIFE REMAINING on the DIC. If the
display shows 100%, the system
is reset.
If the vehicle has a CHANGE
ENGINE OIL SOON message and it
comes back on when the vehicle is
started and/or the OIL LIFE
REMAINING is near 0%, the engine
oil life system has not been reset.
Repeat the procedure.Automatic Transmission
Fluid (6 Speed
Transmission)
When to Check and Change
Automatic Transmission Fluid
It is usually not necessary to check
the transmission fluid level. The only
reason for fluid loss is a
transmission leak or overheated
transmission. If a small leak is
suspected, then use the following
checking procedures to check the
fluid level. However, if there is a
large leak, then it may be necessary
to have the vehicle towed to a
dealer service department and have
it repaired before driving the vehicle
further.
{Caution
Use of the incorrect automatic
transmission fluid may damage
the vehicle, and the damage may (Continued)
Caution (Continued)
not be covered by the vehicle
warranty. Always use the
automatic transmission fluid listed
inRecommended Fluids and
Lubricants on page 11-12.
Change the fluid and filter at the
scheduled maintenance intervals
listed in Maintenance Schedule on
page 11-3. Be sure to use the
transmission fluid listed in
Recommended Fluids and
Lubricants on page 11-12.
How to Check Automatic
Transmission Fluid
{Caution
Too much or too little fluid can
damage the transmission. Too
much can mean that some of the
fluid could come out and fall on
hot engine parts or exhaust
(Continued)

Black plate (19,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-19
Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
coolant. If using this mixture,
nothing else needs to be added.
This mixture:
.Gives freezing protection down
to−37°C (−34°F), outside
temperature.
.Gives boiling protection up to
129°C (265°F), engine
temperature.
.Protects against rust and
corrosion.
.Will not damage aluminum parts.
.Helps keep the proper engine
temperature.
{Caution
If improper coolant mixture,
inhibitors, or additives are used in
the vehicle cooling system, the
engine could overheat and be
damaged. Too much water in the
(Continued)
Caution (Continued)
mixture can freeze and crack
engine cooling parts. The repairs
would not be covered by the
vehicle warranty. Use only the
proper mixture of engine coolant
for the cooling system. See
Recommended Fluids and
Lubricants on page 11-12.
Never dispose of engine coolant by
putting it in the trash, or by pouring
it on the ground, or into sewers,
streams, or bodies of water. Have
the coolant changed by an
authorized service center, familiar
with legal requirements regarding
used coolant disposal. This will help
protect the environment and your
health.
Checking Coolant
The coolant surge tank is in the
engine compartment on the
passenger side of the vehicle. See
Engine Compartment Overview on
page 10-5.
The vehicle must be on a level
surface when checking the coolant
level.
Check to see if coolant is visible in
the coolant surge tank. If the coolant
inside the coolant surge tank is
boiling, do not do anything else until
it cools down. If coolant is visible
but the coolant level is not at or
above the FULL COLD mark, add a
50/50 mixture of clean, drinkable
water and DEX-COOL coolant at the
coolant surge tank, but be sure the
cooling system is cool before this
is done.