fuel system GMC SIERRA 2015 Owner's Guide

Black plate (61,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-61
Return the tires to the
recommended cold tire inflation
pressure when high-speed driving
has ended. SeeVehicle Load Limits
on page 9-15 andTire Pressure on
page 10-59.
Tire Pressure Monitor
System
The Tire Pressure Monitor System
(TPMS) uses radio and sensor
technology to check tire pressure
levels. The TPMS sensors monitor
the air pressure in your tires and
transmit tire pressure readings to a
receiver located in the vehicle.
Each tire, including the spare (if
provided), should be checked
monthly when cold and inflated to
the inflation pressure recommended
by the vehicle manufacturer on the
vehicle placard or tire inflation
pressure label. (If your vehicle has
tires of a different size than the size
indicated on the vehicle placard or tire inflation pressure label, you
should determine the proper tire
inflation pressure for those tires.)
As an added safety feature, your
vehicle has been equipped with a
tire pressure monitoring system
(TPMS) that illuminates a low tire
pressure telltale when one or more
of your tires is significantly
under-inflated.
Accordingly, when the low tire
pressure telltale illuminates, you
should stop and check your tires as
soon as possible, and inflate them
to the proper pressure. Driving on a
significantly under-inflated tire
causes the tire to overheat and can
lead to tire failure. Under-inflation
also reduces fuel efficiency and tire
tread life, and may affect the
vehicle's handling and stopping
ability.
Please note that the TPMS is not a
substitute for proper tire
maintenance, and it is the driver's
responsibility to maintain correct tire
pressure, even if under-inflation hasnot reached the level to trigger
illumination of the TPMS low tire
pressure telltale.
Your vehicle has also been
equipped with a TPMS malfunction
indicator to indicate when the
system is not operating properly.
The TPMS malfunction indicator is
combined with the low tire pressure
telltale. When the system detects a
malfunction, the telltale will flash for
approximately one minute and then
remain continuously illuminated.
This sequence will continue upon
subsequent vehicle start-ups as
long as the malfunction exists.
When the malfunction indicator is
illuminated, the system may not be
able to detect or signal low tire
pressure as intended. TPMS
malfunctions may occur for a variety
of reasons, including the installation
of replacement or alternate tires or
wheels on the vehicle that prevent
the TPMS from functioning properly.
Always check the TPMS malfunction
telltale after replacing one or more
tires or wheels on your vehicle to

Black plate (101,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-101
2500/3500 Series vehicles, at least
every other engine oil change
lubricate the upper and lower
control arm ball joints. Control arm
ball joints on 1500 series vehicles
are maintenance-free.
2500/3500 Series vehicles equipped
with steering linkage, at least every
other engine oil change lubricate the
tie rod ball joints, idler arm pivot
shaft bearings, idler arm socket, and
pitman arm socket.
{Caution
Lubrication of applicable Steering/
Suspension points should not be
done unless temperature is -12°C
(10°F) or higher, or damage could
result.
Body Component Lubrication
Lubricate all key lock cylinders,
hood hinges, liftgate hinges, and the
steel fuel door hinge unless the
components are plastic. Applying
silicone grease on weatherstripswith a clean cloth will make them
last longer, seal better, and not stick
or squeak.
Underbody Maintenance
At least twice a year, spring and fall,
use plain water to flush dirt and
debris from the vehicle's underbody.
Your dealer or an underbody car
washing system can do this. If not
removed, rust and corrosion can
develop.
Sheet Metal Damage
If the vehicle is damaged and
requires sheet metal repair or
replacement, make sure the body
repair shop applies anti-corrosion
material to parts repaired or
replaced to restore corrosion
protection.
Original manufacturer replacement
parts will provide the corrosion
protection while maintaining the
vehicle warranty.
Finish Damage
Quickly repair minor chips and
scratches with touch-up materials
available from your dealer to avoid
corrosion. Larger areas of finish
damage can be corrected in your
dealer's body and paint shop.
Chemical Paint Spotting
Airborne pollutants can fall upon
and attack painted vehicle surfaces
causing blotchy, ring-shaped
discolorations, and small, irregular
dark spots etched into the paint
surface. Refer to
“Finish Care”
previously in this section.
Interior Care
To prevent dirt particle abrasions,
regularly clean the vehicle's interior.
Immediately remove any soils. Note
that newspapers or dark garments
that can transfer color to home
furnishings can also permanently
transfer color to the vehicle's
interior.

Black plate (3,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Service and Maintenance 11-3
Maintenance
Schedule
Owner Checks and Services
At Each Fuel Stop
.Check the engine oil level. See
Engine Oil on page 10-8.
Once a Month
.Check the tire inflation
pressures. See Tire Pressure on
page 10-59.
.Inspect the tires for wear. See
Tire Inspection on page 10-65.
.Check the windshield washer
fluid level. See Washer Fluid on
page 10-25.
Engine Oil Change
When the CHANGE ENGINE OIL
SOON message displays, have the
engine oil and filter changed within
the next 1 000 km/600 mi. If driven
under the best conditions, the
engine oil life system may not
indicate the need for vehicle service for up to a year. The engine oil and
filter must be changed at least once
a year and the oil life system must
be reset. Your trained dealer
technician can perform this work.
If the engine oil life system is reset
accidentally, service the vehicle
within 5 000 km/3,000 mi since the
last service. Reset the oil life
system when the oil is changed.
See
Engine Oil Life System on
page 10-11.
Passenger Compartment Air
Filter
The passenger compartment air
filter removes 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.
Inspect the passenger compartment
air filter every 36 000 km/
22,500 miles or two years,
whichever comes first. Replace if
necessary. More frequent
replacement may be needed if the
vehicle is driven in areas with heavy traffic, areas with poor air quality,
or areas with high dust levels.
Replacement may also be needed if
there is a reduction in air flow,
excessive window fogging, or odors.
Tire Rotation and Required
Services Every 12 000 km/
7,500 mi
Rotate the tires, if recommended for
the vehicle, and perform the
following services. See
Tire
Rotation on page 10-65.
.Check engine oil level and oil
life percentage. If needed,
change engine oil and filter, and
reset oil life system. See Engine
Oil on page 10-8 andEngine Oil
Life System on page 10-11.
.Check engine coolant level. See
Engine Coolant on page 10-18.
.Check windshield washer fluid
level. See Washer Fluid on
page 10-25.

Black plate (4,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
11-4 Service and Maintenance
.Visually inspect windshield wiper
blades for wear, cracking,
or contamination. SeeExterior
Care on page 10-96. Replace
worn or damaged wiper blades.
See Wiper Blade Replacement
on page 10-35.
.Check tire inflation pressures.
See Tire Pressure on
page 10-59.
.Inspect tire wear. See Tire
Inspection on page 10-65.
.Visually check for fluid leaks.
.Inspect engine air cleaner filter.
See Engine Air Cleaner/Filter on
page 10-15.
.Inspect brake system.
.Visually inspect steering,
suspension, and chassis
components for damaged, loose,
or missing parts or signs of wear
at least once a year. See
Exterior Care on page 10-96.
Lubricate the suspension and steering components at least
every other oil change.
(If equipped with grease fittings)
.Check restraint system
components. See
Safety System
Check on page 3-16.
.Visually inspect fuel system for
damage or leaks.
.Visually inspect exhaust system
and nearby heat shields for
loose or damaged parts.
.Lubricate body components. See
Exterior Care on page 10-96.
.Check starter switch. See Starter
Switch Check on page 10-33.
.Check automatic transmission
shift lock control function. See
Automatic Transmission Shift
Lock Control Function Check on
page 10-34.
.Check ignition transmission lock.
See Ignition Transmission Lock
Check on page 10-34.
.Check parking brake and
automatic transmission park
mechanism. See Park Brake and
P (Park) Mechanism Check on
page 10-34.
.Check accelerator pedal for
damage, high effort, or binding.
Replace if needed.
.Visually inspect gas strut for
signs of wear, cracks, or other
damage. Check the hold open
ability of the strut. See your
dealer if service is required.
.Inspect sunroof track and seal,
if equipped. See Sunroof on
page 2-22.
.Verify spare tire key lock
operation and lubricate as
needed. See Tire Changing on
page 10-76.

Black plate (6,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
11-6 Service and Maintenance
Footnotes—Maintenance
Schedule Additional Required
Services —Normal
(1) Or every two years, whichever
comes first. More frequent
replacement may be needed if the
vehicle is driven in areas with heavy
traffic, areas with poor air quality,
or areas with high dust levels.
Replacement may also be needed if
there is a reduction in air flow,
excessive window fogging, or odors. (2)
Check all fuel and vapor lines
and hoses for proper hook-up,
routing, and condition.
(3) Or every four years, whichever
comes first.
(4) Or every five years, whichever
comes first. See Cooling System on
page 10-17. (5)
Or every 10 years, whichever
comes first. Inspect for fraying,
excessive cracking, or damage;
replace, if needed.
(6) Or every three years, whichever
comes first.

Black plate (8,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
11-8 Service and Maintenance
Footnotes—Maintenance
Schedule Additional Required
Services —Severe
(1) Or every two years, whichever
comes first. More frequent
replacement may be needed if the
vehicle is driven in areas with heavy
traffic, areas with poor air quality,
or areas with high dust levels.
Replacement may also be needed if
there is a reduction in air flow,
excessive window fogging, or odors.
(2) Check all fuel and vapor lines
and hoses for proper hook-up,
routing, and condition.
(3) Or every four years, whichever
comes first.
(4) Do not directly power wash the
transfer case output seals. High
pressure water can overcome the
seals and contaminate the transfer
case fluid. Contaminated fluid will
decrease the life of the transfer
case and should be replaced. (5)
Extreme service. For vehicles
mainly driven off-road in four-wheel
drive or used in farming, mining,
forestry, Department of Natural
Resources (DNR), or snow plowing.
(6) Or every five years, whichever
comes first. See Cooling System on
page 10-17.
(7) Or every 10 years, whichever
comes first. Inspect for fraying,
excessive cracking, or damage;
replace, if needed.
(8) Or every three years, whichever
comes first.Special Application
Services
.Severe Commercial Use
Vehicles Only: Lubricate chassis
components every 5 000 km/
3,000 mi.
.Have underbody flushing service
performed. See "Underbody
Maintenance" in Exterior Care
on page 10-96.

Black plate (9,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Service and Maintenance 11-9
Additional
Maintenance and Care
Your vehicle is an important
investment and caring for it properly
may help to avoid future costly
repairs. To maintain vehicle
performance, additional
maintenance services may be
required.
It is recommended that your dealer
perform these services—their
trained dealer technicians know
your vehicle best. Your dealer can
also perform a thorough
assessment with a multi-point
inspection to recommend when your
vehicle may need attention.
The following list is intended to
explain the services and conditions
to look for that may indicate
services are required. Battery
The battery supplies power to start
the engine and operate any
additional electrical accessories.
.To avoid break-down or failure to
start the vehicle, maintain a
battery with full cranking power.
.Trained dealer technicians have
the diagnostic equipment to test
the battery and ensure that the
connections and cables are
corrosion-free.
Belts
.Belts may need replacing if they
squeak or show signs of
cracking or splitting.
.Trained dealer technicians have
access to tools and equipment
to inspect the belts and
recommend adjustment or
replacement when necessary. Brakes
Brakes stop the vehicle and are
crucial to safe driving.
.Signs of brake wear may include
chirping, grinding, or squealing
noises, or difficulty stopping.
.Trained dealer technicians have
access to tools and equipment
to inspect the brakes and
recommend quality parts
engineered for the vehicle.
Fluids
Proper fluid levels and approved
fluids protect the vehicle’s systems
and components. See
Recommended Fluids and
Lubricants on page 11-12 for GM
approved fluids.
.Engine oil and windshield
washer fluid levels should be
checked at every fuel fill.
.Instrument cluster lights may
come on to indicate that fluids
may be low and need to be
filled.

Black plate (14,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
13-14 Customer Information
In Canada, call 1-800-263-3777
(English) or 1-800-263-7854
(French), or write:
General Motors of Canada Limited
Customer Care Centre, Mail Code:
CA1-163-005
1908 Colonel Sam Drive
Oshawa, Ontario L1H 8P7Vehicle Data
Recording and
Privacy
The vehicle has a number of
computers that record information
about the vehicle’s performance and
how it is driven. For example, the
vehicle uses computer modules to
monitor and control engine and
transmission performance, to
monitor the conditions for airbag
deployment and deploy them in a
crash, and, if equipped, to provide
antilock braking to help the driver
control the vehicle. These modules
may store data to help the dealer
technician service the vehicle.
Some modules may also store data
about how the vehicle is operated,
such as rate of fuel consumption or
average speed. These modules may
retain personal preferences, such as
radio presets, seat positions, and
temperature settings.
Event Data Recorders
This vehicle is equipped with an
event data recorder (EDR). The
main purpose of an EDR is to
record, in certain crash or near
crash-like situations, such as an air
bag deployment or hitting a road
obstacle, data that will assist in
understanding how a vehicle’s
systems performed. The EDR is
designed to record data related to
vehicle dynamics and safety
systems for a short period of time,
typically 30 seconds or less. The
EDR in this vehicle is designed to
record such data as:
.How various systems in your
vehicle were operating;
.Whether or not the driver and
passenger safety belts were
buckled/fastened;
.How far (if at all) the driver was
depressing the accelerator and/
or brake pedal; and,
.How fast the vehicle was
traveling.

Black plate (4,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
14-4 OnStar
navigation system in the vehicle (if
equipped). After the call ends, press
the“Go” button on the navigation
screen to begin driving directions.
If directions are downloaded to the
navigation system, the route can
only be canceled through the
navigation system.
Destinations can also be
downloaded on the go. For
information about eNav or
Destination Download, see
www.onstar.com (U.S.) or
www.onstar.ca (Canada).
Connections
The required specific Onstar
subscription plan includes the
services that follow to help
customers stay connected.
For coverage maps, see
www.onstar.com (U.S.) or
www.onstar.ca (Canada). WiFi Connectivity (If Equipped)
The vehicle has a WiFi hotspot that
provides a high-speed, wireless
Internet connection to connect
multiple mobile devices (data plan
required).
1. To retrieve WiFi hotspot
information, press
=and select
or say “WiFi settings.”
2. The WiFi settings will display the WiFi network name/SSID,
passphrase, and level of
encryption.
3. To change the SSID or passphrase, press
Qor call
1-888-4-ONSTAR to connect
with an Advisor.
OnStar RemoteLink
®Mobile App
(If Equipped)
Download the OnStar RemoteLink
mobile app to select Apple
®,
Android™, and BlackBerry®or
Windows 7 or 8 mobile devices.
From the mobile device, check the
vehicle’s fuel level, oil life, or tire pressure (if the vehicle is equipped
with the tire pressure monitoring
system); or activate remote horn
and lights. Also remote start the
vehicle (if factory equipped) or
unlock the doors from anywhere
with a wireless connection (if
equipped with automatic locks).
With a required specific OnStar
subscription plan, a destination can
be sent to the vehicle. For OnStar
RemoteLink information and
compatibility, see www.onstar.com
(U.S.) or www.onstar.ca (Canada).
OnStar RemoteLink
®Key Fob
Services
This feature is included for five
years and allows for remote door
lock/unlock (if equipped with
automatic locks), remote start (if
factory equipped), or activation of
horn and lights from anywhere with
a wireless signal. Download the app
and start using it any time during the
trial period to get started.

Black plate (1,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
INDEX i-1
A
Accessories andModifications . . . . . . . . . . . . . . . . . 10-3
Accessory Power . . . . . . . . . . . . . . 9-29
Active Fuel Management
®. . . . . 9-32
Add-On Electrical Equipment . . . . . . . . . . . . . . . . . . . 9-88
Adding a Snow Plow or Similar Equipment . . . . . . . . . . . . 9-88
Additional Information OnStar
®. . . . . . . . . . . . . . . . . . . . . . 14-6
Additional Maintenance and Care . . . . . . . . . . . . . . . . . . . . . 11-9
Adjustable Throttle and Brake Pedal . . . . . . . . . . . . . . . . . . 9-23
Adjustments
Lumbar, Front Seats . . . . . . . . . . . 3-3
Air Cleaner/Filter, Engine . . . . . 10-15
Air Filter, Passenger Compartment . . . . . . . . . . . . . . . . . 8-5
Air Vents . . . . . . . . . . . . . . . . . . . . . . . 8-4 Airbag System
Check . . . . . . . . . . . . . . . . . . . . . . . . 3-29
How Does an Airbag
Restrain? . . . . . . . . . . . . . . . . . . . 3-22
Passenger Sensing System . . . . . . . . . . . . . . . . . . . . . . 3-24
What Makes an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . 3-22
What Will You See after an Airbag Inflates? . . . . . . . . . . . . . 3-22
When Should an Airbag
Inflate? . . . . . . . . . . . . . . . . . . . . . . 3-20
Where Are the Airbags? . . . . . . 3-18
Airbags Adding Equipment to theVehicle . . . . . . . . . . . . . . . . . . . . . . 3-28
Passenger Status Indicator . . . 5-17
Readiness Light . . . . . . . . . . . . . . 5-16
Servicing Airbag-Equipped Vehicles . . . . . . . . . . . . . . . . . . . . . 3-28
System Check . . . . . . . . . . . . . . . . 3-17
Alarm Vehicle Security . . . . . . . . . . . . . . 2-11
All-Season Tires . . . . . . . . . . . . . . 10-51
All-Terrain Tires . . . . . . . . . . . . . . . 10-52 Antilock Brake
System (ABS) . . . . . . . . . . . . . . . . 9-46
Warning Light . . . . . . . . . . . . . . . . . 5-21
Appearance Care Exterior . . . . . . . . . . . . . . . . . . . . . 10-96
Interior . . . . . . . . . . . . . . . . . . . . . 10-101
Assistance Program,
Roadside . . . . . . . . . . . . . . . . . . . . . 13-5
Assistance Systems for Driving . . . . . . . . . . . . . . . . . . . . . . . 9-59
Assistance Systems for
Parking and Backing . . . . . . . . . 9-56
Automatic Dimming Mirrors . . . . . . . . . . . . . . 2-17
Door Locks . . . . . . . . . . . . . . . . . . . . 2-9
Headlamp System . . . . . . . . . . . . . 6-3
Transmission . . . . . . . . . . . . . . . . . 9-33
Transmission Fluid . . 10-12, 10-15
Automatic Transmission Manual Mode . . . . . . . . . . . . . . . . . 9-36
Shift Lock ControlFunction Check . . . . . . . . . . . 10-34
Auxiliary Roof Mounted Lamp . . . . . . . . . . . 6-5
Axle, Front . . . . . . . . . . . . . . . . . . . . 10-30
Axle, Rear . . . . . . . . . . . . . . . . . . . . 10-31