
Black plate (8,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
11-8 Service and Maintenance
Footnotes—Maintenance
Schedule Additional Required
Services —Severe
a) Extreme service. For vehicles
mainly driven off‐road in four‐wheel
drive or used in farming, mining,
forestry, Department of Natural
Resources (DNR), or snow plowing.
b) Check all fuel and vapor lines
and hoses for proper hook‐up,
routing, and condition. Check that
the purge valve, if the vehicle has
one, works properly. Replace as
needed.
c) Or every four years, whichever
comes first. d)
Do not directly power wash the
transfer case output seals. High
pressure water can overcome the
seals and contaminate the transfer
case fluid. Contaminated fluid will
decrease the life of the transfer
case and should be replaced.
e) Or every five years, whichever
comes first. See Cooling System on
page 10‑18.
f) Or every 10 years, whichever
comes first. Inspect for fraying,
excessive cracking, or damage;
replace, if needed.Special Application
Services
.Vehicles with Dual Wheels:
Check dual wheel nut torque
at 160 km/100 mi, 1 600 km/
1,000 mi and 9 700 km/6,000 mi.
.Severe Commercial Use
Vehicles Only: Lubricate chassis
components every 5 000 km/
3,000 mi.
.Have underbody flushing service
performed once a year.

Black plate (4,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
14-4 OnStar
Connections
OnStar Hands-Free Calling allows
calls to be made and received from
the vehicle. The vehicle can also be
controlled from a cell phone through
the OnStar RemoteLink mobile
app. See www.onstar.com for
coverage maps.
Hands-Free Calling
1. PushX. System responds:
“OnStar ready.”
2. Say “Dial.”System responds:
“Please say the name or number
to call.”
3. Say the entire number without pausing, including a “1”and the
area code. System responds:
“OK calling.”
Retrieve My Number
1. PushX. System responds:
“OnStar ready.”
2. Say “My Number.” System
responds: “Your OnStar
Hands-Free Calling number is.”
End a Call
PushX. System responds: “Call
ended.”
Store a Name Tag for Speed
Dialing
1. PushX. System responds:
“OnStar ready.”
2. Say “Store.” System responds:
“Please say the number you
would like to store.”
3. Say the entire number without pausing. System responds:
“Please say the name tag.”
4. Pick a name tag. “System
responds: ”About to store
5. Say “Yes”or“No” to try again.
System responds: “OK, storing
Place a Call Using a Stored
Number
1. PushX. System responds:
“OnStar ready.”
2. Say “Call
responds: “OK, calling
Verify Minutes and Expiration
PushXand say “minutes” then
“verify” to check how many minutes
remain and their expiration date.
OnStar Mobile App
With an iPhone® or
Android™-based mobile device,
an OnStar RemoteLink mobile app
can be downloaded. The vehicle
can be remote started, if equipped,
or the doors can be unlocked from
anywhere there is cell phone
service. It can also check the fuel
level, tire pressure, and oil life.
It can connect to an OnStar Advisor
anytime. For OnStar mobile app
compatibility or further information,
see www.onstar.com.

Black plate (5,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
INDEX i-5
Engine (cont'd)Cooling System Messages . . . 5-41
Drive Belt Routing . . . . . . . . . . . . 12-6
Exhaust . . . . . . . . . . . . . . . . . . . . . . 9-33
Fan . . . . . . . . . . . . . . . . . . . . . . . . . 10-24
Oil Life System . . . . . . . . . . . . . 10-10
Oil Messages . . . . . . . . . . . . . . . . . 5-42
Oil Pressure Gauge . . . . . . . . . . 5-15
Overheated Protection
Operating Mode . . . . . . . . . . . 10-24
Overheating . . . . . . . . . . . . . . . . 10-22
Power Messages . . . . . . . . . . . . . 5-42
Pressure Light . . . . . . . . . . . . . . . . 5-28
Running While Parked . . . . . . . . 9-34
Starting . . . . . . . . . . . . . . . . . . . . . . . 9-27
Entry Lighting . . . . . . . . . . . . . . . . . . . 6-9
Equipment, Towing . . . . . . . . . . . . 9-94
Event Data Recorders . . . . . . . . 13-19
Exit Lighting . . . . . . . . . . . . . . . . . . . . 6-9
Extender, Safety Belt . . . . . . . . . . 3-20
Exterior Lamp Controls . . . . . . . . . 6-1
Exterior Lamps Off Reminder . . . 6-2F
Fan Engine . . . . . . . . . . . . . . . . . . . . . . 10-24
Fast Idle System . . . . . . . . . . . . . . . 9-29
Features Memory . . . . . . . . . . . . . . . . . . . . . . . 1-14
Filter,
Engine Air Cleaner . . . . . . . . . 10-17
Flash-to-Pass . . . . . . . . . . . . . . . . . . . 6-3
Flashers, Hazard Warning . . . . . . 6-5
Flat Tire . . . . . . . . . . . . . . . . . . . . . . 10-75 Changing . . . . . . . . . . . . . . . . . . . 10-76
Floor Mats . . . . . . . . . . . . . . . . . . .10-104
Fluid AutomaticTransmission . . . . . . . 10-11, 10-14
Brakes . . . . . . . . . . . . . . . . . . . . . . 10-28
Four-Wheel Drive Transfer Case . . . . . . . . . . . . . . . 9-40
Power Steering . . . . . . . . . . . . . 10-25
Washer . . . . . . . . . . . . . . . . . . . . . 10-26 Fog Lamps
Bulb Replacement . . . . . . . . . . . . . 6-6
Folding Mirrors . . . . . . . . . . . . . . . . 2-16
Four-Wheel Drive . . . . . . . 9-40, 10-30
Four-Wheel-Drive Light . . . . . . . . 5-26
Front Axle . . . . . . . . . . . . . . . . . . . . 10-31
Front Fog Lamp Light . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29
Front Seats Adjustment . . . . . . . . . . . . . . . . . . . . 3-3
Heated and Ventilated . . . . . . . . . 3-9
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-68 Additives . . . . . . . . . . . . . . . . . . . . . 9-70
E85 (85% Ethanol) . . . . . . . . . . . 9-71
Economy Driving . . . . . . . . . . . . . 1-36
Filling a Portable FuelContainer . . . . . . . . . . . . . . . . . . . 9-73
Filling the Tank . . . . . . . . . . . . . . . 9-72
Foreign Countries . . . . . . . . . . . . 9-69
Gasoline Specifications . . . . . . . 9-69
Gauge . . . . . . . . . . . . . . . . . . . . . . . . 5-14
Low Fuel Warning Light . . . . . . . 5-28

Black plate (6,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
i-6 INDEX
Fuel (cont'd)Management, Active . . . . . . . . . . 9-32
Recommended . . . . . . . . . . . . . . . 9-68
Requirements, California . . . . . 9-69
System Messages . . . . . . . . . . . . 5-43
Full-Size Spare Tire . . . . . . . . . . 10-87
Fuses Engine CompartmentFuse Block . . . . . . . . . . . . . . . . 10-44
Fuses and Circuit Breakers . . . . . . . . . . . . . . . . . . 10-44
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . . . . 10-48
G
Garage Door Opener . . . . . . . . . . 5-56Programming . . . . . . . . . . . . . . . . . 5-56
Gasoline Specifications . . . . . . . . . . . . . . . . . 9-69 Gauges
Engine Coolant
Temperature . . . . . . . . . . . . . . . . 5-16
Engine Oil Pressure . . . . . . . . . . 5-15
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
Odometer . . . . . . . . . . . . . . . . . . . . . 5-13
Speedometer . . . . . . . . . . . . . . . . . 5-13
Tachometer . . . . . . . . . . . . . . . . . . . 5-13
Trip Odometer . . . . . . . . . . . . . . . . 5-13
Voltmeter . . . . . . . . . . . . . . . . . . . . . 5-16
Warning Lights and Indicators . . . . . . . . . . . . . . . . . . . 5-11
General Information Service and Maintenance . . . . . 11-1
Towing . . . . . . . . . . . . . . . . . . . . . . . . 9-74
Vehicle Care . . . . . . . . . . . . . . . . . . 10-2
Glass Replacement . . . . . . . . . . . 10-37
Glove Box . . . . . . . . . . . . . . . . . . . . . . 4-1
GM Mobility Reimbursement Program . . . . . . . . . . . . . . . . . . . . . . 13-7
H
Halogen Bulbs . . . . . . . . . . . . . . . . 10-39
Hazard Warning Flashers . . . . . . . 6-5
Head Restraints . . . . . . . . . . . . . . . . 3-2
HeadlampsAiming . . . . . . . . . . . . . . . . . . . . . . 10-37
Automatic . . . . . . . . . . . . . . . . . . . . . . 6-4
Bulb Replacement . . . . . . . . . . 10-39
Daytime RunningLamps (DRL) . . . . . . . . . . . . . . . . . 6-3
Flash-to-Pass . . . . . . . . . . . . . . . . . . 6-3
Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . 10-39
High-Beam On Light . . . . . . . . . . 5-29
High/Low Beam Changer . . . . . . 6-3
Heated and Ventilated Front Seats . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Heated Mirrors . . . . . . . . . . . . . . . . . 2-17
Heater Engine Coolant . . . . . . . . . . . . . . . 9-30

Black plate (8,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
i-8 INDEX
LightsAirbag On-Off . . . . . . . . . . . . . . . . . 5-19
Airbag Readiness . . . . . . . . . . . . . 5-18
Antilock Brake System
(ABS) Warning . . . . . . . . . . . . . . 5-26
Brake System Warning . . . . . . . 5-25
Charging System . . . . . . . . . . . . . 5-22
Cruise Control . . . . . . . . . . . . . . . . 5-30
Engine Oil Pressure . . . . . . . . . . 5-28
Flash-to-Pass . . . . . . . . . . . . . . . . . . 6-3
Four-Wheel-Drive . . . . . . . . . . . . . 5-26
Front Fog Lamp . . . . . . . . . . . . . . 5-29
High-Beam On . . . . . . . . . . . . . . . . 5-29
High/Low Beam Changer . . . . . . 6-3
Low Fuel Warning . . . . . . . . . . . . 5-28
Safety Belt Reminders . . . . . . . . 5-17
Security . . . . . . . . . . . . . . . . . . . . . . 5-29
StabiliTrak
®OFF . . . . . . . . . . . . . 5-27
Tire Pressure . . . . . . . . . . . . . . . . . 5-27
Tow/Haul Mode . . . . . . . . . . . . . . . 5-26
Traction Control System (TCS)/StabiliTrak
®. . . . . . . . . . 5-27
Locking Rear Axle . . . . . . . . . . . . . 9-58 Locks
Automatic Door . . . . . . . . . . . . . . . . 2-8
Delayed Locking . . . . . . . . . . . . . . . 2-8
Door . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Lockout Protection . . . . . . . . . . . . . 2-9
Power Door . . . . . . . . . . . . . . . . . . . . 2-8
Safety . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Loss of Control . . . . . . . . . . . . . . . . . 9-5
Low Fuel Warning Light . . . . . . . . 5-28
Lower Anchors and Tethers for Children (LATCH
System) . . . . . . . . . . . . . . . . . . . . . . 3-47
Lumbar Adjustment . . . . . . . . . . . . . 3-4 Front Seats . . . . . . . . . . . . . . . . . . . . 3-4
M
MaintenanceRecords . . . . . . . . . . . . . . . . . . . . .11-16
Maintenance Schedule Recommended Fluidsand Lubricants . . . . . . . . . . . . .11-12
Transfer Case . . . . . . . . . . . . . . . . 9-40
Malfunction Indicator Lamp . . . . 5-22
Manual Mirrors . . . . . . . . . . . . . . . . 2-14 Manual Mode . . . . . . . . . . . . . . . . . . 9-38
Manual Windows . . . . . . . . . . . . . . 2-19
Memory Features . . . . . . . . . . . . . . 1-14
Memory Seats . . . . . . . . . . . . . . . . . . 3-7
Messages
Airbag System . . . . . . . . . . . . . . . . 5-45
Anti-theft Alarm System . . . . . . . 5-45
Battery Voltage andCharging . . . . . . . . . . . . . . . . . . . . 5-39
Brake System . . . . . . . . . . . . . . . . 5-40
Door Ajar . . . . . . . . . . . . . . . . . . . . . 5-40
Engine Cooling System . . . . . . . 5-41
Engine Oil . . . . . . . . . . . . . . . . . . . . 5-42
Engine Power . . . . . . . . . . . . . . . . 5-42
Fuel System . . . . . . . . . . . . . . . . . . 5-43
Key and Lock . . . . . . . . . . . . . . . . . 5-43
Lamp . . . . . . . . . . . . . . . . . . . . . . . . . 5-43
Object Detection System . . . . . 5-43
Ride Control System . . . . . . . . . . 5-44
Starting the Vehicle . . . . . . . . . . . 5-45
Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-45
Transmission . . . . . . . . . . . . . . . . . 5-46
Vehicle . . . . . . . . . . . . . . . . . . . . . . . 5-39
Vehicle Reminder . . . . . . . . . . . . . 5-47
Washer Fluid . . . . . . . . . . . . . . . . . 5-48