service indicator GMC SIERRA 1500 2012 Owners Manual

Black plate (4,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
iv Introduction
Using this Manual
To quickly locate information
about the vehicle, use the Index in
the back of the manual. It is an
alphabetical list of what is in the
manual and the page number where
it can be found.
Danger, Warnings, and
Cautions
Warning messages found on vehicle
labels and in this manual describe
hazards and what to do to avoid or
reduce them.
Dangerindicates a hazard with a
high level of risk which will result in
serious injury or death.
Warning orCaution indicates a
hazard that could result in injury or
death.
{WARNING
These mean there is something
that could hurt you or other
people.
Notice: This means there is
something that could result in
property or vehicle damage. This
would not be covered by the
vehicle's warranty.
A circle with a slash through it is a
safety symbol which means “Do
Not,” “Do not do this,” or“Do not let
this happen.”
Symbols
The vehicle has components and
labels that use symbols instead of
text. Symbols are shown along with
the text describing the operation or
information relating to a specific
component, control, message,
gauge, or indicator.
M: This symbol is shown when
you need to see your owner manual
for additional instructions or
information.
*: This symbol is shown when
you need to see a service manual
for additional instructions or
information.

Black plate (31,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Seats and Restraints 3-31
To turn off the right front passenger
airbag, insert the ignition key into
the switch, push in, and move the
switch to the off position.
The word OFF or the off symbol will
come on in the passenger airbag
status indicator located in the
overhead console to let you know
that the right front passenger airbag
is off, after the system check is
completed. The airbag off light will
come on and stay on to let you
know that the right front passenger's
airbag is off. SeeAirbag On-Off
Light on page 5‑19.
{WARNING
If the airbag readiness light
ever comes on and stays on, it
means that something may be
wrong with the airbag system.
For example, the right front
passenger airbag could inflate
even though the airbag on-off
switch is turned off.
(Continued)
WARNING (Continued)
To help avoid injury to yourself or
others, have the vehicle serviced
right away. SeeAirbag Readiness
Light on page 5‑18 for more
information, including important
safety information.
United States
Canada and Mexico
To turn the right front passenger
airbag on again, insert the ignition
key into the switch, push in, and
move the switch to the on position.
The right front passenger frontal
airbag is now enabled (may inflate).
See Airbag On-Off Light on
page 5‑19 for more information.

Black plate (34,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
3-34 Seats and Restraints
The passenger sensing system is
designed to turn on (may inflate) the
right front passenger frontal airbag
anytime the system senses that a
person of adult size is sitting
properly in the right front
passenger seat.
When the passenger sensing
system has allowed the airbag to be
enabled, the on indicator will light
and stay lit to remind you that the
airbag is active.
For some children, including
children in child restraints, and for
very small adults, the passenger
sensing system may or may not
turn off the right front passenger
frontal airbag, depending upon the
person's seating posture and body
build. Everyone in your 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 5‑18 for more
information, including important
safety information.
If the On Indicator is Lit for 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
(Center Front Seat Position) on
page 3‑58 orSecuring Child
Restraints (Right Front Seat
Position) on page 3‑58 or
Securing Child Restraints (Rear
Seat Position) on page 3‑55.
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.

Black plate (36,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
3-36 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.
If the shoulder portion of the belt is
pulled out all the way, the child
restraint locking feature will be
engaged. This may unintentionally
cause the passenger sensing
system to turn the airbag off for
some adult size occupants. If this
happens, let the belt go back all the
way and start again.
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 3‑37 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 13‑16.
{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
(Continued)

Black plate (63,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Seats and Restraints 3-63
WARNING (Continued)
To help avoid injury to yourself or
others, have the vehicle serviced
right away. SeeAirbag Readiness
Light on page 5‑18 for more
information, including important
safety information.
If the vehicle does not have a rear
seat that will accommodate a
rear-facing child restraint, a
rear-facing child restraint should not
be installed in the vehicle, even if
the airbag is off.
If the child restraint has the
LATCH system, see Lower Anchors
and Tethers for Children (LATCH
System) on page 3‑47 for how and
where to install the child restraint
using LATCH. If a child restraint is
secured using a safety belt and it
uses a top tether, see Lower
Anchors and Tethers for Children
(LATCH System) on page 3‑47 for
top tether anchor locations. Do not secure a child restraint in a
position without a top tether anchor
if a national or local law requires
that the top tether be anchored, or if
the instructions that come with the
child restraint say that the top strap
must be anchored.
In Canada, the law requires that
forward-facing child restraints have
a top tether, and that the tether be
attached.
You will be using the lap-shoulder
belt to secure the child restraint in
this position. Follow the instructions
that came with the child restraint.
1. Move the seat as far back as it
will go before securing the
forward-facing child restraint. If you have no other choice but
to install a rear-facing child
restraint in this seat, make sure
the airbag is off once the child
restraint has been installed.
When the airbag off switch
has turned off the right front
passenger frontal airbag, the off
indicator in the airbag off light
should light and stay lit when
you start the vehicle. See
Airbag
On-Off Light on page 5‑19.
2. Put the child restraint on the seat.
3. Pick up the latch plate, and run the lap and shoulder portions of
the vehicle's safety belt through
or around the restraint. The child
restraint instructions will show
you how.

Black plate (21,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-21
If, after several seconds, both status
indicator lights remain on, or if there
are no lights at all, there may be a
problem with the lights or the airbag
on-off switch. See your dealer for
service.
Passenger Airbag Status
Indicator
If the vehicle has one of the
indicators pictured in the following
illustrations, then the vehicle has a
passenger sensing system for the
right front passenger position unless
there is an airbag off switch located
in the glove box. If there is an
airbag off switch, the vehicle does
not have a passenger system
system. SeeAirbag On-Off Switch
on page 3‑29.
The passenger airbag status
indicator is on the overhead
console. See Passenger Sensing
System on page 3‑32 for important
safety information. In addition, if the vehicle has a
passenger sensing system for the
right front passenger position, the
label on the vehicle's sun visor
refers to
“ADVANCED AIRBAGS”.
United States
Canada and Mexico
When the vehicle is started, the
passenger airbag status indicator
will light ON and OFF, or the symbol for on and off, for several seconds
as a system check. Then, after
several more seconds, the status
indicator will light either ON or OFF,
or either the on or off symbol to let
you know the status of the right front
passenger frontal airbag.
If the word ON or the on symbol is
lit on the passenger airbag status
indicator, it means that the right
front passenger frontal airbag is
enabled (may inflate).
If the word OFF or the off symbol is
lit on the airbag status indicator, it
means that the passenger sensing
system has turned off the right front
passenger frontal airbag.

Black plate (22,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
5-22 Instruments and Controls
If, after several seconds, both status
indicator lights remain on, or if there
are no lights at all, there may be a
problem with the lights or the
passenger sensing system. See
your dealer for service.
{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. SeeAirbag Readiness
Light on page 5‑18 for more
information, including important
safety information.
Charging System Light
This light comes on briefly when the
ignition key is turned to START, but
the engine is not running, as a
check to show it is working.
If it does not, have the vehicle
serviced by your dealer.
The light should go out once
the engine starts. If it stays on,
or comes on while driving, there
could be a problem with the
charging system. A charging system
message in the Driver Information
Center (DIC) can also appear. See
Battery Voltage and Charging
Messages on page 5‑39 for more
information. This light could indicate
that there are problems with a
generator drive belt, or that there
is an electrical problem. Have it checked right away. If the vehicle
must be driven a short distance with
the light on, turn off accessories,
such as the radio and air
conditioner.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.Malfunction
Indicator Lamp
A computer system called OBD II
(On-Board Diagnostics-Second
Generation) monitors the operation
of the vehicle to ensure emissions
are at acceptable levels, to produce
a cleaner environment. This light
comes on when the vehicle is
placed in ON/RUN, as a check to
show it is working. If it does not,
have the vehicle serviced by your
dealer. See
Ignition Positions on
page 9‑26.

Black plate (23,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-23
If the malfunction indicator lamp
comes on and stays on while the
engine is running, this indicates that
there is an OBD II problem and
service is required.
Malfunctions often are indicated by
the system before any problem is
apparent. Being aware of the light
can prevent more serious damage
to the vehicle. This system assists
the service technician in correctly
diagnosing any malfunction.
Notice:If the vehicle is
continually driven with this light
on, the emission controls might
not work as well, the vehicle fuel
economy might not be as good,
and the engine might not run as
smoothly. This could lead to
costly repairs that might not be
covered by the vehicle warranty. Notice:
Modifications made
to the engine, transmission,
exhaust, intake, or fuel system
of the vehicle or the replacement
of the original tires with other
than those of the same Tire
Performance Criteria (TPC) can
affect the vehicle's emission
controls and can cause this light
to come on. Modifications to
these systems could lead to
costly repairs not covered by
the vehicle warranty. This could
also result in a failure to pass a
required Emission Inspection/
Maintenance test. See
Accessories and Modifications on
page 10‑3.
This light comes on during a
malfunction in one of two ways:
Light Flashing: A misfire condition
has been detected. A misfire
increases vehicle emissions and
could damage the emission control
system on the vehicle. Diagnosis
and service might be required. To prevent more serious damage to
the vehicle:
.Reduce vehicle speed.
.Avoid hard accelerations.
.Avoid steep uphill grades.
.If towing a trailer, reduce the
amount of cargo being hauled as
soon as it is possible.
If the light continues to flash, stop
and park the vehicle. Turn the
vehicle off, wait at least 10 seconds,
and restart the engine. If the light is
still flashing, follow the previous
steps and see your dealer for
service as soon as possible.
Light On Steady: An emission
control system malfunction has
been detected on the vehicle.
Diagnosis and service might be
required.

Black plate (26,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
5-26 Instruments and Controls
Antilock Brake System
(ABS) Warning Light
For vehicles with the Antilock Brake
System (ABS), this light comes on
briefly when the engine is started.
If it does not, have the vehicle
serviced by your dealer. If the
system is working normally the
indicator light then goes off.
If the ABS light stays on, turn the
ignition off. If the light comes on
while driving, stop as soon as it is
safely possible and turn the ignition
off. Then start the engine again to
reset the system. If the ABS light
stays on, or comes on again while
driving, the vehicle needs service.
If the regular brake system warning
light is not on, the vehicle still has
brakes, but not antilock brakes.If the regular brake system warning
light is also on, the vehicle does not
have antilock brakes and there is a
problem with the regular brakes.
See
Brake System Warning Light on
page 5‑25.
For vehicles with a Driver
Information Center (DIC), see Brake
System Messages on page 5‑40 for
all brake‐related DIC messages.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Four-Wheel-Drive Light
For vehicles equipped with the
four-wheel-drive light, it comes on
when a vehicle with a manual transfer case is shifted into
four-wheel drive and the front axle
engages.
Some delay between the shifting
and the light coming on is normal.
See
Four-Wheel Drive on page 9‑40
for more information.
Tow/Haul Mode Light
For vehicles with the Tow/Haul
Mode feature, this light comes on
when the Tow/Haul Mode has been
activated.
For more information, see Tow/Haul
Mode on page 9‑39.

Black plate (27,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-27
StabiliTrak®OFF Light
This light comes on briefly while
starting the engine.
If it does not, have the vehicle
serviced by your dealer. If the
system is working normally, the
indicator light then goes off.
Press and release the Traction
Control System (TCS)/StabiliTrak
button to turn off TCS, and a
message displays in the DIC.
Press and briefly hold the TCS/
StabiliTrak button to turn off the
StabiliTrak system; the StabiliTrak
Off light comes on and a message
appears in the Driver Information
Center (DIC).If the StabiliTrak/TCS system is
off, the system does not assist in
controlling the vehicle. Turn on the
StabiliTrak/TCS system and the
indicator light turns off.
See
StabiliTrak
®System on
page 9‑55, and Ride Control System
Messages on page 5‑44 for more
information.
Traction Control System
(TCS)/StabiliTrak®Light
The TCS/StabiliTrak light comes on
briefly when the engine is started.
If the light does not come on or
stays on, have the vehicle serviced
by the dealer. If the system is
working normally, the indicator light
turns off. If the light comes on and stays
on while driving, and a message
displays in the Driver Information
Center (DIC), have the vehicle
serviced by the dealer. See
Ride
Control System Messages on
page 5‑44 for more information.
If the light flashes while driving, this
means that StabiliTrak or TCS is
assisting in controlling the vehicle.
See StabiliTrak
®System on
page 9‑55 for more information.
Tire Pressure Light
For vehicles with the Tire Pressure
Monitor System (TPMS), this light
comes on briefly when the engine
is started. It provides information
about tire pressures and the TPMS.