
Black plate (2,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
2012 GMC Sierra Owner ManualM
Ride Control Systems . . . . . . . . 9-55
Cruise Control . . . . . . . . . . . . . . . . 9-58
Object Detection Systems . . . . 9-61
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . 9-68
Towing . . . . . . . . . . . . . . . . . . . . . . . 9-74
Conversions and
Add-Ons . . . . . . . . . . . . . . . . . . . 9-105
Vehicle Care . . . . . . . . . . . . . . . . . 10-1
General Information . . . . . . . . . . 10-2
Vehicle Checks . . . . . . . . . . . . . . . 10-4
Headlamp Aiming . . . . . . . . . . . 10-37
Bulb Replacement . . . . . . . . . . 10-39
Electrical System . . . . . . . . . . . . 10-43
Wheels and Tires . . . . . . . . . . . 10-50
Jump Starting . . . . . . . . . . . . . . . 10-88
Towing . . . . . . . . . . . . . . . . . . . . . . 10-93
Appearance Care . . . . . . . . . . . 10-98 Service and Maintenance
. . . 11-1
General Information . . . . . . . . . . 11-1
Maintenance Schedule . . . . . . . 11-3
Special Application
Services . . . . . . . . . . . . . . . . . . . . 11-8
Additional Maintenance and Care . . . . . . . . . . . . . . . . . . . . 11-9
Recommended Fluids,
Lubricants, and Parts . . . . . . 11-12
Maintenance Records . . . . . . . 11-16
Technical Data . . . . . . . . . . . . . . . 12-1
Vehicle Identification . . . . . . . . . 12-1
Vehicle Data . . . . . . . . . . . . . . . . . . 12-2 Customer Information
. . . . . . . 13-1
Customer Information . . . . . . . . 13-1
Reporting Safety Defects . . . . 13-17
Vehicle Data Recording and
Privacy . . . . . . . . . . . . . . . . . . . . 13-19
OnStar . . . . . . . . . . . . . . . . . . . . . . . 14-1
OnStar Overview . . . . . . . . . . . . . 14-1
OnStar Services . . . . . . . . . . . . . . 14-2
OnStar Additional
Information . . . . . . . . . . . . . . . . . . 14-5
Index . . . . . . . . . . . . . . . . . . . . . i-1

Black plate (5,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Introduction v
Vehicle Symbol Chart
Here are some additional symbols
that may be found on the vehicle
and what they mean. For more
information on the symbol, refer to
the Index.
0:Adjustable Pedals
9:Airbag Readiness Light
#:Air Conditioning
!:Antilock Brake System (ABS)
%:Audio Steering Wheel Controls
or OnStar®
$: Brake System Warning Light
":Charging System
I:Cruise Control
B: Engine Coolant Temperature
O:Exterior Lamps
#:Fog Lamps
.: Fuel Gauge
+:Fuses
3: Headlamp High/Low-Beam
Changer
j: LATCH System Child
Restraints
*: Malfunction Indicator Lamp
::Oil Pressure
g:Outside Power Foldaway
Mirrors
O: Power
/:Remote Vehicle Start
>:Safety Belt Reminders
7:Tire Pressure Monitor
_: Tow/Haul Mode
d:Traction Control/StabiliTrak®
M:Windshield Washer Fluid

Black plate (3,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
In Brief 1-3
A.Air Vents on page 8‑10.
B. Turn and Lane‐Change Lever. See Turn and Lane-Change
Signals on page 6‑5.
Windshield Wiper/Washer on
page 5‑4.
C. Driver Information Center (DIC) Buttons. See Driver Information
Center (DIC) on page 5‑30.
D. Hazard Warning Flashers on
page 6‑5 (Out of View).
E. Instrument Cluster on
page 5‑12.
F. Shift Lever. See Automatic
Transmission on page 9‑35.
Tow/Haul Selector Button (If
Equipped). See Tow/Haul Mode
on page 9‑39. Range Selection Mode (Allison
Transmission and Hydra-Matic®
6‐Speed Button) (If Equipped).
See
Manual Mode on
page 9‑38.
G. Infotainment on page 7‑1.
H. Instrument Panel Storage on
page 4‑1.
I. Integrated Trailer Brake Controller (If Equipped). See
Trailer Towing on page 9‑78.
J. Exterior Lamp Controls on
page 6‑1.
K. Data Link Connector (DLC) (Out of View). See Malfunction
Indicator Lamp on page 5‑22.
L. Hood Release. See Hood on
page 10‑5. M.
Parking Brake on page 9‑54.
N. Dome Lamps on page 6‑8.
Fog Lamps on page 6‑6
(If Equipped).
O. Cruise Control on page 9‑58.
P. Steering Wheel Adjustment on
page 5‑2.
Q. Horn on page 5‑4.
R. Steering Wheel Controls on
page 5‑2 (If Equipped).
S. Automatic Transfer Case Control (If Equipped). See
Four-Wheel Drive on
page 10‑30.
T. Ashtray (If Equipped). See Ashtrays on page 5‑11 and
Cigarette Lighter on page 5‑10.

Black plate (7,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
In Brief 1-7
A.Air Vents on page 8‑10.
B. Turn and Lane‐Change Lever. See Turn and Lane-Change
Signals on page 6‑5.
Windshield Wiper/Washer on
page 5‑4.
C. Instrument Cluster on
page 5‑12.
D. Hazard Warning Flashers on
page 6‑5 (Out of View).
E. Shift Lever. See Automatic
Transmission on page 9‑35.
Range Selection Mode
(If Equipped). See Manual
Mode on page 9‑38.
F. Tow/Haul Mode on page 9‑39
(If Equipped).
G. Driver Information Center (DIC) Buttons. See Driver Information
Center (DIC) on page 5‑30. H.
Infotainment on page 7‑1.
I. Exterior Lamp Controls on
page 6‑1.
J. Integrated Trailer Brake Controller (If Equipped). See
Trailer Towing on page 9‑78.
K. Dome Lamps on page 6‑8.
L. Automatic Transfer Case Control (If Equipped). See
Four-Wheel Drive on
page 10‑30.
M. Data Link Connector (DLC) (Out of View). See Malfunction
Indicator Lamp on page 5‑22.
N. Hood Release. See Hood on
page 10‑5.
O. Parking Brake on page 9‑54.
P. Cruise Control on page 9‑58. Q.
Steering Wheel Adjustment on
page 5‑2.
R. Horn on page 5‑4.
S. Steering Wheel Controls on
page 5‑2.
T. Climate Control Systems (with
Air Conditioning) on page 8‑1 or
Climate Control Systems (with
Heater Only) on page 8‑4
(If Equipped).
Dual Automatic Climate
Control System on page 8‑5
(If Equipped).
U. Power Outlets on page 5‑9.
Cigarette Lighter (If Equipped).
See Ashtrays on page 5‑11 and
Cigarette Lighter on page 5‑10.

Black plate (18,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
1-18 In Brief
SeePower Mirrors on page 2‑15.
Keep the selector switch in the
center position when not adjusting
either outside mirror.
Manual Mirrors
If the vehicle has manual mirrors,
they can be adjusted by moving the
mirror up and down or left to right to
see a little of the side of the vehicle,
and have a clear view behind the
vehicle.
Manual Folding Mirrors
If the vehicle has manual folding
mirrors, push the mirror toward the
vehicle. Push the mirror outward, to
return to its original position.
Manually fold the mirrors inward
to prevent damage when going
through an automatic car wash.
See Folding Mirrors on page 2‑16. Trailer-Tow Mirrors
If the vehicle has towing mirrors,
they can be adjusted for a clearer
view of the objects behind you.
Manually pull out the mirror head to
extend it for better visibility when
towing a trailer. See
Trailer-Tow
Mirrors on page 2‑15.
Heated Mirrors
For vehicle with heated mirrors:
Press
1to heat the mirrors. If the
vehicle has a towing mirror, only the
upper glass of the mirror is heated.
The lower convex part of the towing
mirrors is not heated.
See “Rear Window Defogger”
under Climate Control Systems
(with Air Conditioning) on page 8‑1
or Climate Control Systems (with
Heater Only) on page 8‑4 orDual
Automatic Climate Control System
on page 8‑5 for more information. Park Tilt Mirrors
If the vehicle has the memory
package, the exterior mirrors tilt
to a preselected position when the
vehicle is in R (Reverse). This
feature lets the driver view the curb
when parallel parking. The mirrors
return to the original position
when the vehicle is shifted out of
R (Reverse), or the ignition is turned
off or to OFF/LOCK.
This feature can be programed
through the Driver Information
Center (DIC). See
Vehicle
Personalization (With DIC Buttons)
on page 5‑48 for more information.
Interior Mirror
Adjustment
Hold the rearview mirror in the
center and move it to view the area
behind the vehicle.

Black plate (25,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
In Brief 1-25
2. Press the plus/minus buttons,located on the steering column
shift lever, to select the desired
range of gears for current driving
conditions. See Manual Mode on
page 9‑38.
While using Range Selection Mode,
cruise control and the Tow/Haul
mode can be used.
Grade Braking is not available when
Range Selection Mode is active.
See Tow/Haul Mode on page 9‑39.
Four-Wheel Drive
If the vehicle has Four-Wheel Drive,
you can send the engine's driving
power to all four wheels for extra
traction.
Transfer Case Buttons
The vehicle will have one of these
three styles of transfer case
controls. Use these controls to
shift into and out of the different
Four-Wheel Drive modes. Manual Transfer Case
This transfer case shift lever is on
the floor to the right of the driver.
Electronic Transfer CaseThis transfer case knob is located
next to the steering column.

Black plate (26,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
1-26 In Brief
Automatic Transfer Case
This transfer case knob is located
next to the steering column.
Each transfer case design offers
different drive options. The list
below describes the different drive
options that may be available.2
m(Two-Wheel-Drive High):
This
setting is used for driving in most
street and highway situations.
AUTO (Automatic Four-Wheel
Drive): This setting is ideal for
use when road surface traction
conditions are variable.
4
m(Four-Wheel High): Use the
Four-Wheel-Drive High position
when extra traction is needed, such
as on snowy or icy roads or in most
off-road situations. N (Neutral):
Shift the transfer case
to Neutral only when towing the
vehicle. See Recreational Vehicle
Towing on page 10‑93 orTrailer
Towing on page 9‑78.
4
n(Four-Wheel-Drive Low): This
setting sends maximum power to
all four wheels. You might choose
Four-Wheel-Drive Low if you are
driving off-road in deep sand, deep
mud, deep snow, and while climbing
or descending steep hills.
See Four-Wheel Drive on
page 9‑40.

Black plate (1,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Keys, Doors, and Windows 2-1
Keys, Doors, and
Windows
Keys and Locks
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Remote Keyless Entry (RKE)System . . . . . . . . . . . . . . . . . . . . . . 2-2
Remote Keyless Entry (RKE) System Operation . . . . . . . . . . . 2-3
Remote Vehicle Start . . . . . . . . . 2-5
Door Locks . . . . . . . . . . . . . . . . . . . 2-7
Power Door Locks . . . . . . . . . . . . 2-8
Delayed Locking . . . . . . . . . . . . . . 2-8
Automatic Door Locks . . . . . . . . . 2-8
Lockout Protection . . . . . . . . . . . . 2-9
Safety Locks . . . . . . . . . . . . . . . . . . 2-9
Doors
Rear Doors (Extended Cab) . . . . . . . . . . . . . . 2-9
Tailgate . . . . . . . . . . . . . . . . . . . . . . 2-10
Vehicle Security
Vehicle Security . . . . . . . . . . . . . . 2-11
Anti-theft Alarm System . . . . . . 2-11
Immobilizer . . . . . . . . . . . . . . . . . . 2-12
Immobilizer Operation . . . . . . . 2-13
Exterior Mirrors
Convex Mirrors . . . . . . . . . . . . . . 2-14
Manual Mirrors . . . . . . . . . . . . . . . 2-14
Trailer-Tow Mirrors . . . . . . . . . . . 2-15
Power Mirrors . . . . . . . . . . . . . . . . 2-15
Folding Mirrors . . . . . . . . . . . . . . . 2-16
Heated Mirrors . . . . . . . . . . . . . . . 2-17
Park Tilt Mirrors . . . . . . . . . . . . . . 2-17
Interior Mirrors
Manual Rearview Mirror . . . . . . 2-18
Automatic Dimming Rearview Mirror . . . . . . . . . . . . . . . . . . . . . . . 2-18
Windows
Windows . . . . . . . . . . . . . . . . . . . . . 2-19
Manual Windows . . . . . . . . . . . . 2-19
Power Windows . . . . . . . . . . . . . 2-20
Rear Windows . . . . . . . . . . . . . . . 2-21
Sun Visors . . . . . . . . . . . . . . . . . . . 2-21
Roof
Sunroof (Extended Cab) . . . . . 2-22
Sunroof (Crew Cab) . . . . . . . . . 2-23