2015 GMC SIERRA DENALI hood open

Black plate (11,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - CRC - 6/20/14
Keys, Doors, and Windows 2-11To remove the tailgate:
1. Raise the tailgate and support it
firmly. Pull out and hold the
cable retaining clip (1). Push the
cable (3) up and off of the
bolt (2). Repeat on the
other side. 2. With the tailgate about halfway
open, lift the right edge of the
tailgate from the lower pivot.
On vehicles with the tailgate
assist feature, raise the tailgate
nearly all the way to the closed
position prior to removing the
left edge.
3. Move the tailgate to the right and
away to release the left edge.
Reverse this procedure to reinstall
the tailgate. Make sure the tailgate
is secure. Vehicle Security This vehicle has theft-deterrent
features; however, they do not make
the vehicle impossible to steal.
Vehicle Alarm System
If equipped with the anti-theft alarm
system, the indicator light, on the
instrument panel near the
windshield, indicates the status of
the system.
Off: Alarm system is disarmed.
On Solid: Vehicle is secured
during the delay to arm the system.
Fast Flash: Vehicle is unsecured.
A door or the hood is open.

Black plate (12,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - CRC - 6/20/14
2-12 Keys, Doors, and Windows Slow Flash: Alarm system is
armed.
Arming the Alarm System 1. Turn off the vehicle.
2. Lock the vehicle with one of the
following: .
Use the Remote Keyless
Entry (RKE) transmitter. .
With a door open, press
Qon the interior of the door.
3. After 30 seconds the alarm
system will arm, and the
indicator light will begin to slowly
flash indicating the alarm system
is operating. Pressing
Q on the
RKE transmitter a second time
will bypass the 30-second delay
and immediately arm the alarm
system.
The theft-deterrent alarm system will
not arm if the doors are locked with
the key. If the driver door is opened without
first unlocking the RKE transmitter,
the horn will chirp and the lights will
flash to indicate pre-alarm. If the
vehicle is not started, or the door is
not unlocked by pressing
K on the
RKE transmitter during the
10-second pre-alarm, the alarm will
be activated.
If a door or the hood is opened
without first disarming the system,
the turn signals will flash and the
horn will sound for about
30 seconds. The alarm system will
then re-arm to monitor for the next
unauthorized event.
Disarming the Alarm System To disarm the alarm system or turn
off the alarm if it has been activated: .
Press
K on the RKE transmitter. .
Start the vehicle. To avoid setting off the alarm by
accident: .
Lock the vehicle after all
occupants have left the vehicle
and all doors are closed. .
Always unlock a door with the
RKE transmitter.
Unlocking the driver door with the
key will not disarm the system or
turn off the alarm.
How to Detect a Tamper
Condition If
K is pressed on the RKE
transmitter and the horn chirps three
times, an alarm occurred previously
while the alarm system was armed.
Immobilizer See Radio Frequency Statement on
page 13-12 .

Black plate (33,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-33
Door Ajar Messages DOOR OPEN This message displays and a chime
may sound if a door is not fully
closed. Stop and turn off the
vehicle, check the door for
obstructions, and close the door
again. Check to see if the message
still appears on the DIC.
HOOD OPEN This message displays and a chime
may sound if the hood is not fully
closed. Stop and turn off the
vehicle, check the hood for
obstructions, and close the hood
again. Check to see if the message
still appears on the DIC. Engine Cooling System
Messages A/C OFF DUE TO HIGH
ENGINE TEMP This message displays when the
engine coolant becomes hotter than
the normal operating temperature.
See Engine Coolant Temperature
Gauge on page 5-13 . To avoid
added strain on a hot engine, the air
conditioning compressor
automatically turns off. When the
coolant temperature returns to
normal, the air conditioning
compressor turns back on. You can
continue to drive your vehicle.
If this message continues to appear,
have the system repaired by your
dealer as soon as possible to avoid
damage to the engine. ENGINE OVERHEATING IDLE
ENGINE This message displays when the
engine coolant temperature is too
hot. Stop and allow the vehicle to
idle until it cools down. See Engine
Coolant Temperature Gauge on
page 5-13 .
When towing, use Tow/Haul mode
to prevent damage to the engine or
transmission. See Tow/Haul Mode
on page 9-39 .
ENGINE OVERHEATED STOP
ENGINE This message displays and a chime
may sound if the engine cooling
system reaches unsafe
temperatures for operation. Stop
and turn off the vehicle as soon as it
is safe to do so to avoid severe
damage. This message clears when
the engine has cooled to a safe
operating temperature.

Black plate (5,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Climate Controls 8-5.
Keep the path under the front
seats clear of objects to help
circulate the air inside of the
vehicle more effectively. .
Use of non-GM approved hood
deflectors can adversely affect
the performance of the system.
Check with your dealer before
adding equipment to the outside
of the vehicle.
Maintenance Passenger Compartment
Air Filter The filter reduces the dust, pollen,
and other airborne irritants from
outside air that is pulled into the
vehicle.
The filter should be replaced as part
of routine scheduled maintenance.
See Maintenance Schedule on
page 11-3 . To find out what type of
filter to use, see Maintenance
Replacement Parts on page 11-14 . 1. Open the lower glove box door
completely.
2. Remove the four screws from
around the lower glove box. The
door does not need to be
removed to access the screws.

Black plate (6,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
8-6 Climate Controls
3. Close the lower glove box door
and pull it from its frame to
remove the entire unit. 4. Release the two tabs holding the
service door. Open the service
door and remove the old filter.
5. Install the new air filter.
6. Close the service door and
secure the tabs.
7. Reverse the steps to reinstall the
glove box.
See your dealer if additional
assistance is needed. Service All vehicles have a label underhood
that identifies the refrigerant used in
the vehicle. The refrigerant system
should only be serviced by trained
and certified technicians. The air
conditioning evaporator should
never be repaired or replaced by
one from a salvage vehicle.
It should only be replaced by a new
evaporator to ensure proper and
safe operation.
During service, all refrigerants
should be reclaimed with proper
equipment. Venting refrigerants
directly to the atmosphere is harmful
to the environment and may also
create unsafe conditions based on
inhalation, combustion, frostbite,
or other health-based concerns.

Black plate (28,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-28 Driving and Operating
Engine Heater The engine heater can provide
easier starting and better fuel
economy during engine warm-up in
cold weather conditions at or below
− 18°C (0°F). Vehicles with an
engine heater should be plugged in
at least four hours before starting.
An internal thermostat in the
plug-end of the cord may exist,
which will prevent engine coolant
heater operation at temperatures
above − 18°C (0°F).
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
To Use the Engine Coolant
Heater
1. Turn off the engine. 2. Open the hood and unwrap the
electrical cord. The cord is
secured to the driver side fender
with a clip, next to the engine
compartment fuse block.
Carefully remove the wire tie
that bundles the electrical plug.
Do not cut the electrical cord.
Check the heater cord for
damage. If it is damaged, do not
use it. See your dealer for a
replacement. Inspect the cord for
damage yearly.
3. Plug the cord into a normal,
grounded 110-volt AC outlet.
{ Warning
Improper use of the heater cord
or an extension cord can damage
the cord and may result in
overheating and fire. .
Plug the cord into a
three-prong electrical utility
receptacle that is protected
(Continued) Warning (Continued) by a ground fault detection
function. An ungrounded
outlet could cause an electric
shock. .
Use a weatherproof,
heavy-duty, 15 amp-rated
extension cord if needed.
Failure to use the
recommended extension cord
in good operating condition,
or using a damaged heater or
extension cord, could make it
overheat and cause a fire,
property damage, electric
shock, and injury. .
Do not operate the vehicle
with the heater cord
permanently attached to the
(Continued)

Black plate (29,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-29Warning (Continued) vehicle. Possible heater cord
and thermostat damage could
occur. .
While in use, do not let the
heater cord touch vehicle
parts or sharp edges. Never
close the hood on the
heater cord. .
Before starting the vehicle,
unplug the cord, reattach the
cover to the plug, and
securely fasten the cord.
Keep the cord away from any
moving parts.
4. Before starting the engine, be
sure to unplug and store the
cord as it was before to keep it
away from moving engine parts.
If you do not, it could be
damaged. The length of time the heater should
remain plugged in depends on
several factors. Ask a dealer in the
area where you will be parking the
vehicle for the best advice on this.
Retained Accessory
Power (RAP) The following vehicle accessories
can be used for up to 10 minutes
after the engine is turned off: .
Audio System .
Power Windows .
OnStar System (if equipped) .
Sunroof (if equipped)
These features work when the key
is in ON/RUN or ACC/
ACCESSORY. Once the key is
turned from ON/RUN to LOCK/OFF,
the windows and sunroof continue
to work up to 10 minutes or until any
door is opened. The radio continues
to work for up to 10 minutes or until
the driver door is opened. Accessory Power Outlets (APOs)
The vehicle may have APOs in
several locations. See Power
Outlets on page 5-5 .
The APOs in the console or center
seat position are powered by RAP.
They will continue to work for up to
10 minutes after the key is turned
from ON/RUN to LOCK/OFF, or until
the driver door is opened.
The APOs on the center stack come
from the factory powered directly
from the vehicle battery, and supply
accessory power at all times,
regardless of ignition key position.
If electronic items are left plugged
into these APOs for long periods of
time with the vehicle off, the vehicle
battery could be drained. The
vehicle may not start if the battery is
allowed to drain for an extended
period of time.

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
{ CautionDo 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