service GMC SIERRA 1500 2012 Service Manual

Black plate (11,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Infotainment System 7-11
Satellite Radio
XM™Satellite Radio Service
XM is a satellite radio service based
in the 48 contiguous United States
and 10 Canadian provinces. XM
Satellite Radio has a wide variety of
programming and commercial-free
music, coast to coast, and in
digital-quality sound. A service
fee is required to receive the XM
service. If the service needs to be
reactivated, the radio will display
“No Subscription Please Renew
on channel XM1.” For more
information, contact XM at
www.xmradio.com or
1-800-929-2100 in the U.S.,
and www.xmradio.ca or
1-877-438-9677 in Canada.
4(Information) (XM Satellite Radio
Service): For vehicles with XM,
press
4to display additional text
information related to the current
XM channel. If information is
available, the song title information
displays on the top line of the display and artist information
displays on the bottom line.
When information is not available,
“NO INFO”
displays.
Finding a Channel
BAND:Press to switch between
AM, FM, or XM™, if equipped.
f(Tune): Turn to manually select
an XM channel.
©SEEK: Press to go to the
previous XM channel.
¨SEEK: Press to go to the next
XM channel.
sREV: Press to go to the
previous XM category.
\FWD: Press to go to the next
XM category.
FAV (Favorites): Press to select
different favorites pages for stored
radio stations.
CAT (Category): The CAT button is
used to find XM channels when the
radio is in the XM mode.
Finding a Category (CAT)
Station
To find XM channels in a category:
1. Press the CAT button to display the category tabs. Continue
pressing the CAT button until the
desired category name displays.
.Radios with CD and DVD
can also navigate the
category list by pressing the
\FWD or thesREV
buttons.
2. Press either of the two softkeys below the desired category tab
to immediately tune to the first
XM station in that category.
To go to the previous or next XM
station in the selected category,
do one of the following:
.Turn thefknob.
.Press the softkey below the
right or left arrows in the
category tab.
.Press©SEEK or¨SEEK.

Black plate (13,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Infotainment System 7-13
XM Radio Messages
XL (Explicit Language
Channels):These channels, or
any others, can be blocked at a
customer's request, by calling
1-800-929-2100 in the U.S. and
1-877-438-9677 in Canada.
XM Updating: The encryption code
in the receiver is being updated, and
no action is required. This process
should take no longer than
30 seconds.
No XM Signal: The system is
functioning correctly, but the vehicle
is in a location that is blocking the
XM signal. When the vehicle is
moved into an open area, the signal
should return.
Loading XM: The audio system is
acquiring and processing audio and
text data. No action is needed. This
message should disappear shortly.
Channel Off Air: This channel is
not currently in service. Tune in to
another channel. Channel Unauth:
This channel is
blocked or cannot be received with
your XM subscription package.
Channel Unavail: This previously
assigned channel is no longer
assigned. Tune to another station.
If this station was one of the
presets, choose another station for
that preset button.
No Artist Info: No artist
information is available at this time
on this channel. The system is
working properly.
No Title Info: No song title
information is available at this time
on this channel. The system is
working properly.
No CAT Info: No category
information is available at this time
on this channel. The system is
working properly.
No Information: No text or
informational messages are
available at this time on this
channel. The system is working
properly. No Subscription Please Renew:
The XM subscription needs to
be reactivated. Contact XM at
www.xmradio.com or call
1-800-929-2100 in the U.S.
and www.xmradio.ca or call
1-877-438-9677 in Canada.
CAT Not Found:
There are no
channels available for the selected
category. The system is working
properly.
XM Theftlocked: The XM receiver
in the vehicle could have previously
been in another vehicle. For security
purposes, XM receivers cannot be
swapped between vehicles. If this
message is received after having
the vehicle serviced, check with
your dealer.
XM Radio ID: If tuned to channel 0,
this message alternates with the
XM Radio eight‐digit radio ID label.
This label is needed to activate the
service.

Black plate (14,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
7-14 Infotainment System
Unknown:If this message is
received when tuned to channel 0,
there could be a receiver fault.
Consult with your dealer.
Check Antenna: If this message
does not clear within a short period
of time, the receiver or antenna
could have a fault. Consult with your
dealer.
Check XM Receivr: If this
message does not clear within a
short period of time, the receiver
could have a fault. Consult with your
dealer.
XM Not Available: If this message
does not clear within a short period
of time, the receiver could have a
fault. Consult with your dealer.
Radio Reception
Frequency interference and static
can occur during normal radio
reception if items such as cell phone
chargers, vehicle convenience
accessories, and external electronic
devices are plugged into the
accessory power outlet. If there is interference or static, unplug the
item from the accessory power
outlet.
AM
The range for most AM stations is
greater than for FM, especially at
night. The longer range can cause
station frequencies to interfere
with each other. For better radio
reception, most AM radio stations
boost the power levels during the
day, and then reduce these levels
during the night. Static can also
occur when things like storms and
power lines interfere with radio
reception. When this happens, try
reducing the treble on the radio.
FM Stereo
FM signals only reach about
16 to 65 km (10 to 40 mi). Although
the radio has a built-in electronic
circuit that automatically works to
reduce interference, some static
can occur, especially around tall
buildings or hills, causing the sound
to fade in and out.
XM™
Satellite Radio Service
XM Satellite Radio Service gives
digital radio reception from coast to
coast in the 48 contiguous United
States, and in Canada. Just as
with FM, tall buildings or hills can
interfere with satellite radio signals,
causing the sound to fade in and
out. In addition, traveling or standing
under heavy foliage, bridges,
garages, or tunnels may cause loss
of the XM signal for a period of time.
Cellular Phone Usage
Cellular phone usage may cause
interference with the vehicle's radio.
This interference may occur when
making or receiving phone calls,
charging the phone's battery,
or simply having the phone on. This
interference causes an increased
level of static while listening to the
radio. If static is received while
listening to the radio, unplug the
cellular phone and turn it off.

Black plate (53,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Infotainment System 7-53
Receiving a Call
When an incoming call is received,
the audio system mutes and a ring
tone is heard in the vehicle.
.Pressb/gto answer the call.
.Pressc/xto ignore a call.
Call Waiting
Call waiting must be supported on
the cell phone and enabled by the
wireless service carrier.
.Pressb/gto answer an
incoming call when another call
is active. The original call is
placed on hold.
.Pressb/gagain to return to
the original call.
.To ignore the incoming call, no
action is required.
.Pressc/xto disconnect the
current call and switch to the call
on hold.
Three‐Way Calling
Three‐way calling must be
supported on the cell phone and
enabled by the wireless service
carrier.
1. While on a call, press
b/g.
2. Say “Three‐way call.”
3. Use the dial or call command to dial the number of the third party
to be called.
4. Once the call is connected, press
b/gto link all callers
together.
Ending a Call
Pressc/xto end a call.
Muting a Call
During a call, all sounds from inside
the vehicle can be muted so that the
person on the other end of the call
cannot hear them.
.To mute a call, pressb/g, and
then say “Mute call.”
.To cancel mute, pressb/g,
and then say “Un‐mute call.”
Transferring a Call
Audio can be transferred between
the Bluetooth system and the cell
phone.
The cell phone must be paired and
connected with the Bluetooth
system before a call can be
transferred. The connection process
can take up to two minutes after the
ignition is turned to ON/RUN.

Black plate (6,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-6 Driving and Operating
.Try to avoid sudden steering,
acceleration, or braking,
including reducing vehicle speed
by shifting to a lower gear. Any
sudden changes could cause
the tires to slide.
Remember: Antilock brakes help
avoid only the braking skid.
Off-Road Driving
Four-wheel-drive vehicles can be
used for off-road driving. Vehicles
without four-wheel drive and
vehicles not equipped with All
Terrain (AT) or On-Off Road (OOR)
tires must not be driven off-road
except on a level, solid surface. To
contact the tire manufacturer for
more information about the original
equipment tires, see the Limited
Warranty and Owner Assistance
Information manual.
Controlling the vehicle is the key to
successful off-road driving. One of
the best ways to control the vehicle
is to control the speed.
{WARNING
When driving off-road, bouncing
and quick changes in direction
can easily throw you out of
position. This could cause you to
lose control and crash. You and
your passengers should always
wear safety belts.
Before Driving Off-Road
.Have all necessary maintenance
and service work completed.
.Fuel the vehicle, fill fluid levels,
and check inflation pressure in
all tires, including the spare,
if equipped.
.Read all the information about
four-wheel-drive vehicles in this
manual.
.Make sure all underbody
shields, if equipped, are properly
attached.
.Know the local laws that apply to
off-road driving. To gain more ground clearance if
needed, it may be necessary to
remove the front fascia lower
air dam.
Notice:
Operating the vehicle
for extended periods without
the front fascia lower air dam
installed can cause improper air
flow to the engine. Re‐attach the
front fascia air dam after off-road
driving.
Loading the Vehicle for
Off-Road Driving
{WARNING
.Unsecured cargo on the
load floor can be tossed
about when driving over
rough terrain. You or your
passengers can be struck by
flying objects. Secure the
cargo properly.
(Continued)

Black plate (11,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-11
After operation in mud or sand,
have the brake linings cleaned and
checked. These substances can
cause glazing and uneven braking.
Check the body structure, steering,
suspension, wheels, tires, and
exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
More frequent maintenance
service is required. Refer to the
Maintenance Schedule for more
information.
Driving on Wet Roads
Rain and wet roads can reduce
vehicle traction and affect your
ability to stop and accelerate.
Always drive slower in these types
of driving conditions and avoid
driving through large puddles and
deep‐standing or flowing water.
{WARNING
Wet brakes can cause crashes.
They might not work as well in a
quick stop and could cause
pulling to one side. You could
lose control of the vehicle.
After driving through a large
puddle of water or a car/vehicle
wash, lightly apply the brake
pedal until the brakes work
normally.
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be
very cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water
can build up under the vehicle's
tires so they actually ride on the
water. This can happen if the road
is wet enough and you are going
fast enough. When the vehicle is
hydroplaning, it has little or no
contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.Allow extra following distance.
.Pass with caution.
.Keep windshield wiping
equipment in good shape.
.Keep the windshield washer fluid
reservoir filled.

Black plate (12,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-12 Driving and Operating
.Have good tires with proper
tread depth. SeeTires on
page 10‑50.
.Turn off cruise control.
Highway Hypnosis
Always be alert and pay attention to
your surroundings while driving.
If you become tired or sleepy, find
a safe place to park the vehicle
and rest.
Other driving tips include:
.Keep the vehicle well ventilated.
.Keep the interior
temperature cool.
.Keep your eyes moving —scan
the road ahead and to the sides.
.Check the rearview mirror and
vehicle instruments often.
Hill and Mountain Roads
Driving on steep hills or through
mountains is different than driving
on flat or rolling terrain. Tips for
driving in these conditions include:
.Keep the vehicle serviced and in
good shape.
.Check all fluid levels and brakes,
tires, cooling system, and
transmission.
.Shift to a lower gear when going
down steep or long hills.
{WARNING
If you do not shift down, the
brakes could get so hot that they
would not work well. You would
then have poor braking or even
none going down a hill. You could
crash. Shift down to let the engine
assist the brakes on a steep
downhill slope.
{WARNING
Coasting downhill in N (Neutral)
or with the ignition off is
dangerous. The brakes will have
to do all the work of slowing down
and they could get so hot that
they would not work well. You
would then have poor braking or
even none going down a hill. You
could crash. Always have the
engine running and the vehicle in
gear when going downhill.

Black plate (27,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-27
The steering can bind with the
wheels turned off center. If this
happens, move the steering wheel
from right to left while turning the
key to ACC/ACCESSORY. If this
does not work, then the vehicle
needs service.
Notice:Using a tool to force the
key to turn in the ignition could
cause damage to the switch or
break the key. Use the correct
key, make sure it is all the way in,
and turn it only with your hand.
If the key cannot be turned by
hand, see your dealer.
B (ACC/ACCESSORY): This
position lets things like the radio
and the windshield wipers operate
while the engine is off. Use this
position if the vehicle must be
pushed or towed.
C (ON/RUN): This position can
be used to operate the electrical
accessories and to display some
instrument panel cluster warning
and indicator lights. This position
can also be used for service and diagnostics, and to verify the
proper operation of the malfunction
indicator lamp as may be required
for emission inspection purposes.
The switch stays in this position
when the engine is running. The
transmission is also unlocked in this
position on automatic transmission
vehicles.
If you leave the key in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. You may not be able to
start the vehicle if the battery is
allowed to drain for an extended
period of time.
D (START):
This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.
A warning tone will sound when
the driver door is opened and the
ignition is in ACC/ACCESSORY or
LOCK/OFF, and the key is in the
ignition.Starting the Engine
If the vehicle has a diesel engine,
see the Duramax® diesel
supplement for more information.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Notice: Do not try to shift to
P (Park) if the vehicle is moving.
If you do, you could damage the
transmission. Shift to P (Park)
only when the vehicle is stopped.
Move the shift lever to P (Park) or
N (Neutral). The engine will not start
in any other position. To restart the
engine when the vehicle is already
moving, use N (Neutral) only.
Notice: If you add electrical parts
or accessories, you could change
the way the engine operates. Any
resulting damage would not be
covered by the vehicle warranty.
See Add-On Electrical Equipment
on page 9‑105.

Black plate (32,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
9-32 Driving and Operating
When you are ready to drive, move
the shift lever out of P (Park) before
you release the parking brake.
If torque lock does occur, you may
need to have another vehicle push
yours a little uphill to take some of
the pressure from the parking pawl
in the transmission, then you will be
able to pull the shift lever out of
P (Park).
Shifting out of Park
This vehicle is equipped with
an electronic shift lock release
system. The shift lock release is
designed to:
.Prevent ignition key removal
unless the shift lever is in
P (Park) with the shift lever
button fully released.
.Prevent movement of the shift
lever out of P (Park), unless the
ignition is in ON/RUN or ACC/
ACCESSORY and the regular
brake pedal is applied.The shift lock release is always
functional except in the case of
an uncharged or low voltage (less
than 9 volt) battery.
If the vehicle has an uncharged
battery or a battery with low voltage,
try charging or jump starting the
battery. See
Jump Starting on
page 10‑88 for more information.
To shift out of P (Park) use the
following:
1. Apply the brake pedal.
2. Move the shift lever to the desired position.
If you still are unable to shift out of
P (Park):
1. Ease the pressure on the shift lever.
2. While holding down the brake pedal, press the shift lever all
the way into P (Park).
3. Move the shift lever to the desired position. If you are still having a problem
shifting, then have the vehicle
serviced soon.
Parking over Things
That Burn
{WARNING
Things that can burn could touch
hot exhaust parts under the
vehicle and ignite. Do not park
over papers, leaves, dry grass,
or other things that can burn.
Active Fuel Management®
Vehicles with V8 engines may
have Active Fuel Management™.
This system allows the engine to
operate on either all or half of its
cylinders, depending on the driving
conditions.

Black plate (45,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-45
Shift the transfer case in one
continuous motion into or out of the
N (Neutral) position.
Electronic Transfer Case
The transfer case knob is located
next to the steering column.
Use the dial to shift into and out of
four-wheel drive.
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m 4m4n N
Normal YES Severe YES
Extreme YES
Vehicle in Tow* YES
*See Recreational Vehicle Towing on page 10‑93 orTowing the Vehicle on
page 10‑93.
You can choose among four driving
settings:
Indicator lights in the dial show
which setting you are in. The
indicator lights will come on briefly
when you turn on the ignition and
one will stay on. If the lights do not
come on, you should take the
vehicle to your dealer for service.
An indicator light flashes while
shifting the transfer case and
remains illuminated when the shift is complete. If for some reason the
transfer case cannot make a
requested shift, it will return to the
last chosen setting.
2
m(Two-Wheel Drive High):
This
setting is used for driving in most
street and highway situations.
The front axle is not engaged in
Two-Wheel Drive. This setting also
provides the best fuel economy.