
Black plate (19,1)GMC Sierra Owner Manual - 2011
Instruments and Controls 5-19
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 5‑24 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
When the engine is started, a chime
sounds for several seconds to
remind a driver to fasten the safety
belt, unless the driver safety belt is
already buckled.
The safety belt light flashes for
several seconds, then comes on
solid for several more.
This chime and light sequence
are repeated if the driver remains
unbuckled and the vehicle is in
motion. If the driver safety belt is
already buckled, neither the chime
nor the light comes on.

Black plate (20,1)GMC Sierra Owner Manual - 2011
5-20 Instruments and Controls
Passenger Safety Belt
Reminder Light
For vehicles equipped with the
passenger safety belt reminder
light, several seconds after the
engine is started, a chime sounds
for several seconds to remind the
front passenger to buckle their
safety belt. The passenger safety
belt light, located on the overhead
console, comes on and stays on for
several seconds, flashes for several
more seconds and then comes on
solid for several more.
This chime and light sequence is
repeated if the passenger remains
unbuckled and the vehicle is in
motion.
If the passenger safety belt is
buckled, neither the chime nor the
light comes on.
The front passenger safety belt
warning light and chime may turn
on if an object is put on the seat
such as a briefcase, handbag,
grocery bag, laptop or other
electronic device. To turn off the
warning light and or chime, remove
the object from the seat or buckle
the safety belt.
Airbag Readiness Light
The system checks the airbag's
electrical system for possible
malfunctions. If the light stays
on it indicates there is an electrical
problem. The system check
includes the airbag sensor, the
pretensioners, the airbag modules,
the wiring, and the crash sensing
and diagnostic module. For more
information on the airbag system,
seeAirbag System on page 3‑29.
The airbag readiness light comes
on solid for a few seconds when the
engine is started. If the light does
not come on then, have it fixed
immediately.

Black plate (21,1)GMC Sierra Owner Manual - 2011
Instruments and Controls 5-21
{WARNING
If the airbag readiness light stays
on after the vehicle is started or
comes on while driving, it means
the airbag system might not be
working properly. The airbags in
the vehicle might not inflate in a
crash, or they could even inflate
without a crash. To help avoid
injury, have the vehicle serviced
right away.
If there is a problem with the airbag
system, a Driver Information Center
(DIC) message can also come on.
See Airbag System Messages on
page 5‑48 for more information.
Airbag On-Off Light
If the vehicle has an airbag on-off
switch, it also has a passenger
airbag status indicator located in the
overhead console.
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, will light for several
seconds as a system check. Then, after several more seconds,
the status indicator ON or OFF,
or either the on or off symbol, will
light to let you know the status of
the right front passenger frontal
airbag.
When the right front passenger
airbag is manually turned off using
the airbag on-off switch in the glove
box, the indicator light OFF or the
off symbol will come on and stay on
as a reminder that the airbag has
been turned off. This light will go off
when the airbag has been turned
on. See
Airbag On-Off Switch on
page 3‑37 for more information,
including important safety
information.

Black plate (22,1)GMC Sierra Owner Manual - 2011
5-22 Instruments and Controls
United StatesCanada and Mexico
{WARNING
If the right front passenger airbag
is turned off for a person who is
not in a risk group identified by
the national government, that
person will not have the extra
protection of an airbag. In a
crash, the airbag will not be able
to inflate and help protect the
person sitting there.(Continued)
WARNING (Continued)
Do not turn off the passenger
airbag unless the person sitting
there is in a risk group identified
by the national government.
SeeAirbag On-Off Switch on
page 3‑37 for more on this,
including important safety
information.
{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)

Black plate (23,1)GMC Sierra Owner Manual - 2011
Instruments and Controls 5-23
WARNING (Continued)
To help avoid injury to yourself or
others, have the vehicle serviced
right away. SeeAirbag Readiness
Light on page 5‑20 for more
information, including important
safety information.
If the word ON or the on symbol
is lit, it means that the right front
passenger frontal airbag is enabled
(may inflate). See Airbag On-Off
Switch on page 3‑37 for more
information, including important
safety information.
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. See Airbag On-Off Switch
on page 3‑37.
The passenger airbag status
indicator is on the overhead
console. See Passenger Sensing
System on page 3‑40 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.

Black plate (24,1)GMC Sierra Owner Manual - 2011
5-24 Instruments and Controls
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.
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 5‑20 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 5‑41 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.
For vehicles with a Hybrid, see
the Hybrid Supplement for more
information.

Black plate (25,1)GMC Sierra Owner Manual - 2011
Instruments and Controls 5-25
Malfunction
Indicator Lamp
A computer system called OBD II
(On-Board Diagnostics-Second
Generation) monitors operation of
the fuel, ignition, and emission
control systems. It ensures that
emissions are at acceptable levels
for the life of the vehicle, helping to
produce a cleaner environment.
This light should come on when the
ignition is on, 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.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, after a while, 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.

Black plate (26,1)GMC Sierra Owner Manual - 2011
5-26 Instruments and Controls
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, when
it is safe to do so, stop the vehicle.
Find a safe place to 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. The following may correct an
emissions system malfunction:
.Make sure the fuel cap is
fully installed. See
Filling
the Tank on page 9‑88.
The diagnostic system can
determine if the fuel cap has
been left off or improperly
installed. A loose or missing fuel
cap allows fuel to evaporate into
the atmosphere. A few driving
trips with the cap properly
installed should turn the light off.
.Make sure the electrical system
is not wet. The system could
be wet if the vehicle was driven
through a deep puddle of water.
The condition is usually
corrected when the electrical
system dries out. A few driving
trips should turn the light off.
.Make sure to fuel the vehicle
with quality fuel. Poor fuel quality
causes the engine not to run as
efficiently as designed and can
cause: stalling after start-up,
stalling when the vehicle is
changed into gear, misfiring,
hesitation on acceleration,
or stumbling on acceleration.
These conditions might go away
once the engine is warmed up.
If one or more of these
conditions occurs, change the
fuel brand used. It will require at
least one full tank of the proper
fuel to turn the light off.
See Recommended Fuel on
page 9‑84.
If none of the above have made
the light turn off, your dealer can
check the vehicle. The dealer
has the proper test equipment
and diagnostic tools to fix any
mechanical or electrical problems
that might have developed.