2012 GMC SIERRA 1500 air condition

Black plate (59,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Seats and Restraints 3-59
{WARNING
A child in a rear-facing child
restraint can be seriously
injured or killed if the right front
passenger airbag inflates. This
is because the back of the
rear-facing child restraint would
be very close to the inflating
airbag. A child in a forward-facing
child restraint can be seriously
injured or killed if the right front
passenger airbag inflates and the
passenger seat is in a forward
position.
The vehicle may have a
passenger sensing system which
is designed to turn off the right
front passenger frontal airbag
under certain conditions.
Even if the passenger sensing
system, if equipped, has turned
off the right front passenger
frontal airbag, no system is(Continued)
WARNING (Continued)
fail-safe. No one can
guarantee that an airbag will
not deploy under some unusual
circumstance, even though it is
turned off.
Secure rear-facing child restraints
in a rear seat, even if the
airbag is off. If you secure a
forward-facing child restraint in
the right front seat, always move
the front passenger seat as far
back as it will go. It is better to
secure the child restraint in a
rear seat.
SeePassenger Sensing System
on page 3‑32 for additional
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 you secure a child
restraint 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 seat 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.

Black plate (17,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-17
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.
SeeCharging System Light on
page 5‑22 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.
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
panel cluster.
When the vehicle is started, this
light flashes and a chime may come
on to remind the driver to fasten
their safety belt. Then the light stays
on solid until the belt is buckled.
This cycle my continue several
times if the driver remains or
becomes unbuckled while the
vehicle is moving.
If the driver safety belt is buckled,
neither the light nor the chime
comes on.

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 (41,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-41
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.
LEFT REAR DOOR OPEN
(Crew Cab)
This message displays and a chime
may sound if the driver side rear
door is not fully closed and the
vehicle is shifted out of P (Park).
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.
PASSENGER DOOR OPEN
This message displays and a chime
may sound if the front passenger
door is not fully closed and the
vehicle is shifted out of P (Park).
Stop and turn off the vehicle, checkthe door for obstructions, and close
the door again. Check to see if the
message still appears on the DIC.
RIGHT REAR DOOR OPEN
(Crew Cab)
This message displays and a chime
may sound if the passenger side
rear door is not fully closed and the
vehicle is shifted out of P (Park).
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.
Engine Cooling System
Messages
Notice:
If you drive the vehicle
while the engine is overheating,
severe engine damage may
occur. If an overheat warning
appears on the instrument panel
cluster and/or DIC, stop the
vehicle as soon as possible.
See Engine Overheating on
page 10‑22 for more information.
ENGINE HOT A/C (Air
Conditioning) TURNED OFF
This message displays when the
engine coolant becomes hotter than
the normal operating temperature.
SeeEngine Coolant Temperature
Gauge on page 5‑16. 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 OVERHEATED 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 5‑16.

Black plate (45,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-45
STABILITRAK OFF may also
display when the stability control
has been automatically disabled.
There are several conditions that
can cause this message to appear.
.One condition is overheating,
which could occur if StabiliTrak
activates continuously for an
extended period of time.
.The message also displays if the
brake system warning light is on.
SeeBrake System Warning
Light on page 5‑25.
.The message could display if the
stability system takes longer
than usual to complete its
diagnostic checks due to driving
conditions.
.The message displays if an
engine or vehicle related
problem has been detected and
the vehicle needs service. See
your dealer. The message turns off as soon as
the conditions that caused the
message to be displayed are no
longer present.
Airbag System Messages
SERVICE AIR BAG
This message displays if there is a
problem with the airbag system.
Have your dealer inspect the
system for problems. See
Airbag
Readiness Light on page 5‑18 and
Airbag System on page 3‑21 for
more information.
Anti-theft Alarm System
Messages
SERVICE THEFT DETERRENT
SYSTEM
This message displays when there
is a problem with the theft-deterrent
system. The vehicle may or may not
restart so you may want to take the
vehicle to your dealer before turning off the engine. See
Immobilizer
Operation on page 2‑13 for more
information.
Starting the Vehicle
Messages
FAST IDLE ON
If your vehicle has this feature, this
message displays when the fast idle
feature is on. See Fast Idle System
on page 9‑29 for more information.
Tire Messages
SERVICE TIRE MONITOR
SYSTEM
If the vehicle has the Tire Pressure
Monitor System (TPMS), this
message displays if a part on the
system is not working properly.
The tire pressure light also flashes
and then remains on during the
same ignition cycle. See Tire
Pressure Light on page 5‑27.

Black plate (46,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
5-46 Instruments and Controls
Several conditions may cause this
message to appear. SeeTire
Pressure Monitor Operation on
page 10‑62 for more information.
If the warning comes on and stays
on, there may be a problem with the
TPMS. See your dealer.
TIRE LEARNING ACTIVE
If the vehicle has the Tire Pressure
Monitor System (TPMS), this
message displays when the system
is re-learning the tire positions on
your vehicle. The tire positions must
be re-learned after rotating the tires
or after replacing a tire or sensor.
See Tire Inspection on page 10‑65,
Tire Rotation on page 10‑65, Tire
Pressure Monitor System on
page 10‑60, and Tire Pressure on
page 10‑58 for more information.
TIRE LOW ADD AIR TO TIRE
If the vehicle has the Tire Pressure
Monitor System (TPMS), this
message displays when the
pressure in one or more of the
vehicle's tires is low. This message also displays LEFT FRT (left front),
RIGHT FRT (right front), LEFT RR
(left rear), or RIGHT RR (right rear)
to indicate the location of the low
tire. The low tire pressure warning
light will also come on. See
Tire
Pressure Light on page 5‑27. You
can receive more than one tire
pressure message at a time. To
read the other messages that may
have been sent at the same time,
press the set/reset button or the
trip odometer reset stem. If a tire
pressure message appears on the
DIC, stop as soon as you can. Have
the tire pressures checked and set
to those shown on the Tire Loading
Information label. See Tires on
page 10‑50, Vehicle Load Limits on
page 9‑16, and Tire Pressure on
page 10‑58. The DIC also shows
the tire pressure values. See Driver
Information Center (DIC) on
page 5‑30.
Transmission Messages
SERVICE 4 WHEEL DRIVE
If the vehicle has four-wheel
drive, this message may display
if a problem occurs with the
four-wheel-drive system. If this
message appears, stop as soon as
possible and turn off the vehicle.
Make sure the key is in the LOCK/
OFF position for at least one minute
and then restart the vehicle and
check for the message on the DIC
display. If the message is still
displayed or appears again
when you begin driving, the
four-wheel-drive system needs
service. See your dealer.

Black plate (47,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Instruments and Controls 5-47
TRANSMISSION HOT IDLE
ENGINE
Notice:Do not drive the vehicle
while the transmission fluid is
overheating and the transmission
temperature warning is displayed
on the instrument panel cluster
and/or DIC, or the transmission
can be damaged. This could lead
to costly repairs that would not
be covered by the warranty.
This message displays and a chime
may sound if the transmission fluid
in the vehicle gets hot. Driving with
the transmission fluid temperature
high can cause damage to the
vehicle. Stop the vehicle and let it
idle to allow the transmission to
cool. This message clears and
the chime stops when the fluid
temperature reaches a safe level.
Vehicle Reminder
Messages
CHECK TRAILER WIRING
On vehicles with the Integrated
Trailer Brake Control (ITBC) system,
this message may display and a
chime may sound when one of the
following conditions exists:
.A trailer with electric brakes
becomes disconnected from the
vehicle.
‐ If the disconnect occurs while
the vehicle is stopped, this
message clears itself after a
short time.
‐ If the disconnect occurs while
the vehicle is moving, this
message stays on until the
ignition is turned off.
.There is a short in the wiring to
the electric trailer brakes.
When this message displays, power
is no longer available to the trailer
brakes. As soon as it is safe to do so,
carefully pull the vehicle over to the
side of the road and turn the ignition
off. Check the wiring connection to
the trailer and turn the ignition back
on. This message clears if the trailer
is reconnected. This message also
clears if you acknowledge it. If this
message still displays, either the
vehicle or the trailer needs service.
See your dealer.
See
“Integrated Trailer Brake
Control System” underTowing
Equipment on page 9‑94 for more
information.
ICE POSSIBLE DRIVE
WITH CARE
This message displays when ice
conditions are possible.
TRAILER CONNECTED
On vehicles with the Integrated
Trailer Brake Control (ITBC) system,
this message displays briefly when
a trailer with electric brakes is first
connected to the vehicle.