
Black plate (67,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-67
Lightly coat the center of the
wheel hub with wheel bearing
grease after a wheel change or
tire rotation to prevent corrosion
or rust build-up. Do not get
grease on the flat wheel
mounting surface or on the
wheel nuts or bolts.
Reset the Tire Pressure Monitor
System (TPMS), if the vehicle
has one. SeeTire Pressure
Monitor Operation on
page 10‑62.
Check that the spare tire, if the
vehicle has one, is stored
properly. Push, pull, and then
try to rotate or turn the tire. If it
moves, tighten the cable. See
“Storing a Flat or Spare Tire and
Tools” underTire Changing on
page 10‑76.Dual Tire Rotation
When the vehicle is new,
or whenever a wheel, wheel
bolt, or wheel nut is replaced,
check the wheel nut torque
after 160, 1 600, and 10 000 km
(100, 1,000, and 6,000 mi) of
driving. For proper torque and
wheel nut tightening information,
see “Removing the Spare Tire and
Tools” underTire Changing on
page 10‑76.
The outer tire on a dual wheel setup
generally wears faster than the
inner tire. Tires last longer and wear
more evenly if they are rotated. See
Tire Inspection on page 10‑65 and
Tire Rotation on page 10‑65. Also
see Maintenance Schedule on
page 11‑3.{WARNING
If the vehicle is operated with a
tire that is underinflated, the tire
can overheat. An overheated tire
can lose air suddenly or catch
fire. You or others could be
injured. Properly inflate all tires,
including the spare.
See Tire Pressure on page 10‑58,
for information on proper tire
inflation.

Black plate (68,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-68 Vehicle Care
When It Is Time for New
Tires
Factors, such as maintenance,
temperatures, driving speeds,
vehicle loading, and road conditions
affect the wear rate of the tires.
Treadwear indicators are one way
to tell when it is time for new tires.
Treadwear indicators appear when
the tires have only 1.6 mm (1/16 in)
or less of tread remaining. Some
commercial truck tires may not
have treadwear indicators. SeeTireInspection on page 10‑65
andTire
Rotation on page 10‑65 for
additional information.
The rubber in tires ages over time.
This also applies to the spare tire,
if the vehicle has one, even if it is
never used. Multiple conditions
including temperatures, loading
conditions, and inflation pressure
maintenance affect how fast aging
takes place. Tires will typically need
to be replaced due to wear before
they may need to be replaced
due to age. Consult the tire
manufacturer for more information
on when tires should be replaced.
Vehicle Storage
Tires age when stored normally
mounted on a parked vehicle. Park
a vehicle that will be stored for at
least a month in a cool, dry, clean
area away from direct sunlight to
slow aging. This area should be
free of grease, gasoline or other
substances that can deteriorate
rubber. Parking for an extended period can
cause flat spots on the tires that
may result in vibrations while
driving. When storing a vehicle for
at least a month, remove the tires
or raise the vehicle to reduce the
weight from the tires.
Buying New Tires
GM has developed and matched
specific tires for the vehicle. The
original equipment tires installed
were designed to meet General
Motors Tire Performance Criteria
Specification (TPC Spec) system
rating. When replacement tires are
needed, GM strongly recommends
buying tires with the same TPC
Spec rating.
GM's exclusive TPC Spec system
considers over a dozen critical
specifications that impact the
overall performance of the
vehicle, including brake system
performance, ride and handling,
traction control, and tire pressure
monitoring performance. GM's TPC

Black plate (71,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-71
nominal rim diameters of
10 to 12 inches (25 to 30 cm),
or to some limited-production
tires.
While the tires available on
General Motors passenger cars
and light trucks may vary with
respect to these grades, they
must also conform to federal
safety requirements and
additional General Motors Tire
Performance Criteria (TPC)
standards.
All Passenger Car Tires Must
Conform to Federal Safety
Requirements In Addition To
These Grades.
Treadwear
The treadwear grade is a
comparative rating based on the
wear rate of the tire when tested
under controlled conditions on
a specified government test
course. For example, a tiregraded 150 would wear one and
a half (1½) times as well on the
government course as a tire
graded 100. The relative
performance of tires depends
upon the actual conditions of
their use, however, and may
depart significantly from the
norm due to variations in
driving habits, service practices
and differences in road
characteristics and climate.
Traction
–AA, A, B, C
The traction grades, from
highest to lowest, are AA, A, B,
and C. Those grades represent
the tire's ability to stop on wet
pavement as measured under
controlled conditions on
specified government test
surfaces of asphalt and
concrete. A tire marked C may
have poor traction performance. Warning: The traction grade
assigned to this tire is based on
straight-ahead braking traction
tests, and does not include
acceleration, cornering,
hydroplaning, or peak traction
characteristics.
Temperature
–A, B, C
The temperature grades
are A (the highest), B, and C,
representing the tire's resistance
to the generation of heat and
its ability to dissipate heat
when tested under controlled
conditions on a specified
indoor laboratory test wheel.
Sustained high temperature can
cause the material of the tire to
degenerate and reduce tire life,
and excessive temperature
can lead to sudden tire failure.

Black plate (90,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-90 Vehicle Care
If your vehicle has a gasoline
engine, the remote negative (-)
terminal is a stud located on the
right front of the engine, where
the negative battery cable
attaches.
If your vehicle has a diesel
engine, the remote negative (-)
terminal is the negative (-) post
on the auxiliary battery on the
driver side of the engine
compartment.For more information on
the location of the remote
positive (+) and remote
negative (−) terminals, see
Engine Compartment Overview
on page 10‑6
{WARNING
An electric fan can start up even
when the engine is not running
and can injure you. Keep hands,
clothing and tools away from any
underhood electric fan.
{WARNING
Using an open flame near a
battery can cause battery gas to
explode. People have been hurt
doing this, and some have been
blinded. Use a flashlight if you
need more light.
(Continued)
WARNING (Continued)
Be sure the battery has enough
water. You do not need to add
water to the battery installed in
your new vehicle. But if a battery
has filler caps, be sure the right
amount of fluid is there. If it is low,
add water to take care of that
first. If you do not, explosive gas
could be present.
Battery fluid contains acid that
can burn you. Do not get it on
you. If you accidentally get it in
your eyes or on your skin, flush
the place with water and get
medical help immediately.

Black plate (98,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-98 Vehicle Care
6. Use an adequate clampingdevice designed for towing to
ensure that the front wheels are
locked into the straight position.
{WARNING
Shifting a four-wheel-drive
vehicle's transfer case into
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). The driver or others
could be injured. Make sure the
parking brake is firmly set before
the transfer case is shifted to
N (Neutral).
7. Shift the transfer case to N (Neutral). See “Shifting into
Neutral” underFour-Wheel Drive
on page 9‑40 for the proper
procedure to select the neutral
position for the vehicle.
8. Turn the ignition to LOCK/OFF.
After towing, see “Shifting Out of
Neutral” underFour-Wheel Drive on
page 9‑40.
Appearance Care
Exterior Care
Washing the Vehicle
To preserve the vehicle's finish,
wash it often and out of direct
sunlight.
Notice: Do not use petroleum
based, acidic, or abrasive
cleaning agents as they can
damage the vehicle's paint,
metal, or plastic parts. If damage
occurs, it would not be covered
by the vehicle's warranty.
Approved cleaning products
can be obtained from your
dealer. Follow all manufacturer
directions regarding correct
product usage, necessary safety
precautions, and appropriate
disposal of any vehicle care
product.
Notice: Avoid using high
pressure washes closer than
30 cm (12 in) to the surface of the
vehicle. Use of power washers exceeding 8,274 kPa (1,200 psi)
can result in damage or removal
of paint and decals.
Rinse the vehicle well, before
washing and after, to remove all
cleaning agents completely. If they
are allowed to dry on the surface,
they could stain.
Dry the finish with a soft, clean
chamois or an all-cotton towel to
avoid surface scratches and water
spotting.
Finish Care
Application of aftermarket clearcoat
sealant/wax materials is not
recommended. If painted surfaces
are damaged, see your dealer to
have the damage assessed and
repaired. Foreign materials such
as calcium chloride and other salts,
ice melting agents, road oil and tar,
tree sap, bird droppings, chemicals
from industrial chimneys, etc., can
damage the vehicle's finish if they
remain on painted surfaces. Wash
the vehicle as soon as possible.
If necessary, use non-abrasive

Black plate (9,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Service and Maintenance 11-9
Additional
Maintenance and Care
Your vehicle is an important
investment and caring for it
properly may help to avoid
future costly repairs. To maintain
vehicle performance, additional
maintenance services may be
required. It is recommended
that your dealer perform these
services—their trained dealer
technicians know your vehicle
best. Your dealer can also
perform a thorough assessment
with a multi‐point inspection to
recommend when your vehicle may
need attention. The following list is
intended to explain the services
and conditions to look for that may
indicate services are required. Battery
The battery supplies power to
start the engine and operate any
additional electrical accessories.
.To avoid break‐down or failure
to start the vehicle, maintain a
battery with full cranking power.
.Trained dealer technicians have
the diagnostic equipment to test
the battery and ensure that the
connections and cables are
corrosion‐free.
Belts
.Belts may need replacing if
they squeak or show signs of
cracking or splitting.
.Trained dealer technicians
can inspect the belts and
recommend replacement when
necessary. Brakes
Brakes stop the vehicle and are
crucial to safe driving.
.Signs of brake wear may include
chirping, grinding, or squealing
noises, or difficulty stopping.
.Trained dealer technicians have
access to tools and equipment
to inspect the brakes and
recommend quality parts
engineered for the vehicle.
Fluids
Proper fluid levels and approved
fluids protect the vehicle’s
systems and components. See
Recommended Fluids and
Lubricants on page 11‑12 for GM
approved fluids.
.Engine oil and windshield
washer fluid levels should be
checked at every fuel fill.
.Instrument cluster lights may
come on to indicate that fluids
may be low and need to be
filled.

Black plate (10,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
11-10 Service and Maintenance
Hoses
Hoses transport fluids and should
be regularly inspected to ensure
that there are no cracks or leaks.
With a multi‐point inspection, your
dealer can inspect the hoses and
advise if replacement is needed.
Lamps
Properly working headlamps,
taillamps, and brake lamps are
important to see and be seen on
the road.
.Signs that the headlamps need
attention include dimming, failure
to light, cracking, or damage.
The brake lamps need to be
checked periodically to ensure
that they light when braking.
.With a multi‐point inspection,
your dealer can check the lamps
and note any concerns.Shocks and Struts
Shocks and struts help aid in control
for a smoother ride.
.Signs of wear may include
steering wheel vibration,
bounce/sway while braking,
longer stopping distance,
or uneven tire wear.
.As part of the multi‐point
inspection, trained dealer
technicians can visually inspect
the shocks and struts for
signs of leaking, blown seals,
or damage, and can advise
when service is needed.
Tires
Tires need to be properly inflated,
rotated, and balanced. Maintaining
the tires can save money, fuel, and
can reduce the risk of tire failure.
.Signs that the tires need to be
replaced include three or more
visible treadwear indicators; cord
or fabric showing through the rubber; cracks or cuts in the
tread or sidewall; or a bulge or
split in the tire.
.Trained dealer technicians can
inspect and recommend the
right tires. Your dealer can also
provide tire/wheel balancing
services to ensure smooth
vehicle operation at all speeds.
Your dealer sells and services
name brand tires.
Vehicle Care
To help keep the vehicle looking
like new, vehicle care products are
available from your dealer. For
information on how to clean and
protect the vehicle’s interior and
exterior, see Interior Care on
page 10‑101 andExterior Care on
page 10‑98.

Black plate (1,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
OnStar 14-1
OnStar
OnStar Overview
OnStar Overview . . . . . . . . . . . . 14-1
OnStar Services
Emergency . . . . . . . . . . . . . . . . . . 14-2
Security . . . . . . . . . . . . . . . . . . . . . . 14-2
Navigation . . . . . . . . . . . . . . . . . . . 14-2
Connections . . . . . . . . . . . . . . . . . 14-4
Diagnostics . . . . . . . . . . . . . . . . . . 14-5
OnStar Additional Information
OnStar AdditionalInformation . . . . . . . . . . . . . . . . . 14-5
OnStar Overview
If equipped, this vehicle has a
comprehensive, in-vehicle system
that can connect to a live Advisor
for Emergency, Security, Navigation,
Connection, and Diagnostic
Services.
The OnStar system status light is
next to the OnStar buttons. If the
status light is:
.Solid Green: System is ready.
.Flashing Green: On a call.
.Red: Indicates a problem.
Push
Qor call 1‐888‐4‐ONSTAR
(1‐888‐466‐7827) to speak to an
Advisor. Push
Xto:
.Make a call, end a call,
or answer an incoming call.
.Give OnStar Hands-Free Calling
voice commands.
.Give OnStar Turn-by-Turn
Navigation voice commands.
Requires the available Directions
and Connections service plan.
Push
Qto connect to a live
Advisor to:
.Verify account information or
update contact information.
.Get driving directions. Requires
the available Directions and
Connections service plan.
.Receive On-Demand
Diagnostics for a check on the
vehicle’s key operating systems.
.Receive Roadside Assistance.