2015 GMC SIERRA service

Black plate (24,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
3-24 Seats and Restraints
other parts. The service manual
for the vehicle covers the need
to replace other parts.
.The vehicle has a crash sensing
and diagnostic module which
records information after a
crash. SeeVehicle Data
Recording and Privacy on
page 13-14 andEvent Data
Recorders on page 13-14.
.Let only qualified technicians
work on the airbag systems.
Improper service can mean that
an airbag system will not work
properly. See your dealer for
service.
Passenger Sensing
System
The vehicle may have a passenger
sensing system for the front
outboard passenger position.
The passenger airbag status
indicator will light on the overhead
console when the vehicle is started.
United States
Canada and Mexico
The words ON and OFF, or the
symbol for on and off, will be visible
during the system check. When the
system check is complete, either the
word ON or OFF, or the symbol for
on or off, will be visible. See
Passenger Airbag Status Indicator
on page 5-17.
The passenger sensing system
turns off the front outboard
passenger frontal airbag under certain conditions. No other airbag
is affected by the passenger
sensing system.
The passenger sensing system
works with sensors that are part of
the front outboard passenger seat
and safety belt. The sensors are
designed to detect the presence of
a properly seated occupant and
determine if the front outboard
passenger frontal airbag should be
allowed to inflate or not.
According to accident statistics,
children are safer when properly
secured in a rear seat in the correct
child restraint for their weight
and size.
Whenever possible, children aged
12 and under should be secured in
a rear seating position.
Never put a rear-facing child seat in
the front. This is because the risk to
the rear-facing child is so great,
if the airbag deploys.

Black plate (26,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
3-26 Seats and Restraints
For some children, including
children in child restraints, and for
very small adults, the passenger
sensing system may or may not turn
off the front outboard passenger
frontal airbag, depending upon the
person's seating posture and body
build. Everyone in the vehicle who
has outgrown child restraints should
wear a safety belt
properly—whether or not there is
an airbag for that person.
{Warning
If the airbag readiness light ever
comes on and stays on, it means
that something may be wrong
with the airbag system. To help
avoid injury to yourself or others,
have the vehicle serviced right
away. See Airbag Readiness
Light on page 5-16 for more
information, including important
safety information.
If the On Indicator Is Lit for a
Child Restraint
The passenger sensing system is
designed to turn off the front
outboard passenger frontal airbag if
the system determines that an infant
is present in a child restraint. If a
child restraint has been installed
and the on indicator is lit:
1. Turn the vehicle off.
2. Remove the child restraint from the vehicle.
3. Remove any additional items from the seat such as blankets,
cushions, seat covers, seat
heaters, or seat massagers.
4. Reinstall the child restraint following the directions provided
by the child restraint
manufacturer and refer to
Securing Child Restraints (Rear
Seat) on page 3-45 orSecuring
Child Restraints (Front
Passenger Seat) on page 3-47.
Even if the child restraint is
equipped with a safety belt lock-off, make sure the safety
belt retractor is locked by pulling
the shoulder belt all the way out
of the retractor before tightening
the safety belt. When the
retractor lock is set, the belt can
be tightened but not pulled out of
the retractor.
5. If, after reinstalling the child restraint and restarting the
vehicle, the on indicator is still lit,
turn the vehicle off. Then slightly
recline the vehicle seatback and
adjust the seat cushion,
if adjustable, to make sure that
the vehicle seatback is not
pushing the child restraint into
the seat cushion.
Also make sure the child
restraint is not trapped under the
vehicle head restraint. If this
happens, adjust the head
restraint. See Head Restraints
on page 3-2.
6. Restart the vehicle.

Black plate (28,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
3-28 Seats and Restraints
Additional Factors Affecting
System Operation
Safety belts help keep the
passenger in position on the seat
during vehicle maneuvers and
braking, which helps the passenger
sensing system maintain the
passenger airbag status. See
“Safety Belts”and“Child Restraints”
in the Index for additional
information about the importance of
proper restraint use.
A thick layer of additional material,
such as a blanket or cushion,
or aftermarket equipment such as
seat covers, seat heaters, and seat
massagers can affect how well the
passenger sensing system
operates. We recommend that you
not use seat covers or other
aftermarket equipment except when
approved by GM for your specific
vehicle. See Adding Equipment to
the Airbag-Equipped Vehicle on
page 3-28 for more information
about modifications that can affect
how the system operates. The on indicator may be lit if an
object, such as a briefcase,
handbag, grocery bag, laptop,
or other electronic device, is put on
an unoccupied seat. If this is not
desired, remove the object from
the seat.
{Warning
Stowing of articles under the
passenger seat or between the
passenger seat cushion and
seatback may interfere with the
proper operation of the passenger
sensing system.
Servicing the
Airbag-Equipped Vehicle
Airbags affect how the vehicle
should be serviced. There are parts
of the airbag system in several
places around the vehicle. Your
dealer and the service manual have
information about servicing the
vehicle and the airbag system.
To purchase a service manual, see
Service Publications Ordering
Information on page 13-11.
{Warning
For up to 10 seconds after the
vehicle is turned off and the
battery is disconnected, an airbag
can still inflate during improper
service. You can be injured if you
are close to an airbag when it
inflates. Avoid yellow connectors.
They are probably part of the
airbag system. Be sure to follow
proper service procedures, and
make sure the person performing
work for you is qualified to do so.
Adding Equipment to the
Airbag-Equipped Vehicle
Adding accessories that change the
vehicle's frame, bumper system,
height, front end, or side sheet
metal, may keep the airbag system
from working properly. The

Black plate (29,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Seats and Restraints 3-29
operation of the airbag system can
also be affected by changing or
moving any parts of the front seats,
safety belts, the airbag sensing and
diagnostic module, steering wheel,
instrument panel, roof-rail airbag
modules, ceiling headliner or pillar
garnish trim, overhead console,
front sensors, side impact sensors,
or airbag wiring.
Your dealer and the service manual
have information about the location
of the airbag sensors, sensing and
diagnostic module, and airbag
wiring.
In addition, the vehicle may have a
passenger sensing system for the
front outboard passenger position,
which includes sensors that are part
of the passenger seat. The
passenger sensing system may not
operate properly if the original seat
trim is replaced with non-GM
covers, upholstery, or trim; or with
GM covers, upholstery, or trim
designed for a different vehicle. Any
object, such as an aftermarket seat
heater or a comfort-enhancing pador device, installed under or on top
of the seat fabric, could also
interfere with the operation of the
passenger sensing system. This
could either prevent proper
deployment of the passenger
airbag(s) or prevent the passenger
sensing system from properly
turning off the passenger airbag(s).
See
Passenger Sensing System on
page 3-24.
If the vehicle has rollover roof-rail
airbags, see Different Size Tires
and Wheels on page 10-70 for
additional important information.
If a snow plow is added to the
vehicle, the airbags should still work
properly. The airbag systems were
designed to work properly under a
wide range of conditions, including
snow plowing with vehicles that
have the optional snow plow prep
package (RPO VYU). Do not
change or defeat the snow plow's
“tripping mechanism.” If you do, it
can damage the snow plow and the
vehicle, and may cause an airbag
deployment. If you have to modify your vehicle
because you have a disability and
you have questions about whether
the modifications will affect the
vehicle's airbag system, or if you
have questions about whether the
airbag system will be affected if the
vehicle is modified for any other
reason, call Customer Assistance.
See
Customer Assistance Offices
on page 13-3.
Airbag System Check
The airbag system does not need
regularly scheduled maintenance or
replacement. Make sure the airbag
readiness light is working. See
Airbag Readiness Light on
page 5-16.
{Caution
If an airbag covering is damaged,
opened, or broken, the airbag
may not work properly. Do not
open or break the airbag
(Continued)

Black plate (30,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
3-30 Seats and Restraints
Caution (Continued)
coverings. If there are any
opened or broken airbag
coverings, have the airbag
covering and/or airbag module
replaced. For the location of the
airbags, seeWhere Are the
Airbags? on page 3-18. See your
dealer for service.
Replacing Airbag System
Parts after a Crash
{Warning
A crash can damage the airbag
systems in the vehicle.
A damaged airbag system may
not work properly and may not
protect you and your
passenger(s) in a crash, resulting
in serious injury or even death. To
help make sure the airbag
(Continued)
Warning (Continued)
systems are working properly
after a crash, have them
inspected and any necessary
replacements made as soon as
possible.
If an airbag inflates, you will need to
replace airbag system parts. See
your dealer for service.
If the airbag readiness light stays on
after the vehicle is started or comes
on when you are driving, the airbag
system may not work properly. Have
the vehicle serviced right away. See
Airbag Readiness Light on
page 5-16.
Child Restraints
Older Children
Older children who have outgrown
booster seats should wear the
vehicle safety belts.

Black plate (12,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
5-12 Instruments and Controls
Fuel Gauge
Standard Theme Shown
When the ignition is on, the fuel
gauge indicates about how much
fuel is left in the tank.
There is an arrow near the fuel
gauge pointing to the side of the
vehicle the fuel door is on.
When the indicator nears empty, the
low fuel light comes on. There still is
a little fuel left, but the vehicle
should be refueled soon. Here are four things that some
owners ask about. None of these
show a problem with the fuel gauge:
.At the service station, the fuel
pump shuts off before the gauge
reads full.
.It takes a little more or less fuel
to fill up than the gauge
indicated. For example, the
gauge may have indicated the
tank was half full, but it actually
took a little more or less than
half the tank's capacity to fill
the tank.
.The gauge moves a little while
turning a corner or speeding up.
.The gauge takes a few seconds
to stabilize after the ignition is
turned on, and goes back to
empty when the ignition is
turned off.
Engine Oil Pressure
Gauge
Metric, Standard Theme Shown

Black plate (13,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-13
English, Standard Theme Shown
The engine oil pressure gauge
shows the engine oil pressure
in kPa (kilopascals) or psi (pounds
per square inch) when the engine is
running.
Oil pressure can vary with engine
speed, outside temperature and oil
viscosity.
A reading outside the normal
operating range can be caused by a
dangerously low oil level or some
other problem causing low oil
pressure. Check the vehicle's oil as
soon as possible. See
“OIL PRESSURE LOW STOP
ENGINE” underEngine Oil
Messages on page 5-34 andEngine
Oil on page 10-8.
{Caution
Lack of proper engine oil
maintenance can damage the
engine. Driving with the engine
oil low can also damage the
engine. The repairs would not be
covered by the vehicle warranty.
Check the oil level as soon as
possible. Add oil if required, but if
the oil level is within the operating
range and the oil pressure is still
low, have the vehicle serviced.
Always follow the maintenance
schedule for changing engine oil.
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
Engine Coolant
Temperature Gauge
Metric, Standard Theme Shown

Black plate (15,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-15
{Caution
Do not drive the vehicle while the
transmission fluid is overheating,
or the transmission can be
damaged. This could lead to
costly repairs that would not be
covered by the warranty.
Voltmeter Gauge
Standard Theme Shown
When the ignition is on, this gauge
indicates the battery voltage. When the engine is running, this
gauge shows the condition of the
charging system. The gauge can
transition from a higher to lower or a
lower to higher reading. This is
normal. If the vehicle is operating
outside the normal operating range,
the charging system light comes on.
See
Charging System Light on
page 5-18 for more information. The
voltmeter gauge may also read
lower when in fuel economy mode.
This is normal.
Readings outside the normal
operating range can also occur
when a large number of electrical
accessories are operating in the
vehicle and the engine is left idling
for an extended period. This
condition is normal since the
charging system is not able to
provide full power at engine idle. As
engine speeds are increased, this
condition should correct itself as
higher engine speeds allow the
charging system to create maximum
power. The vehicle can only be driven for a
short time with the readings outside
the normal operating range. If the
vehicle must be driven, turn off all
accessories, such as the radio and
air conditioner and unplug all
chargers and accessories.
Readings outside the normal
operating range indicate a possible
problem in the electrical system.
Have the vehicle serviced as soon
as possible.
Safety Belt Reminders
Driver Safety Belt Reminder
Light
There is a driver safety belt
reminder light on the instrument
cluster.