Page 466 of 594

Black plate (42,1)GMC Sierra Owner Manual - 2011
10-42 Vehicle Care
Headlamp Aiming
The vehicle has a visual optical
headlamp aiming system. The aim
of the headlamps has been preset
at the factory and should need no
further adjustment.
However, if the vehicle is damaged
in a crash, the aim of the headlamps
may be affected and adjustment
may be necessary.
If oncoming vehicles flash their high
beams at you, this may mean the
vertical aim of the headlamps needs
to be adjusted.
It is recommended that the vehicle
be taken to the dealer for service if
the headlamps need to be adjusted.
It is possible, however, to re-aim the
headlamps as described.The vehicle should:.Be placed so the headlamps
are 7.6 m (25 ft) from a
light‐colored wall.
.Have all four tires on a level
surface which is level all the
way to the wall.
.Be placed so it is perpendicular
to the wall.
.Not have any snow, ice, or mud
on it.
.Be fully assembled and all other
work stopped while headlamp
aiming is being performed.
.Be loaded with a full tank of
fuel and one person or 75 kg
(160 lbs) sitting on the
driver seat.
.Have the tires properly inflated.
.Have the spare tire in its proper
location in the vehicle.Headlamp aiming is done with the
vehicle's low-beam headlamps.
The high-beam headlamps will be
correctly aimed if the low-beam
headlamps are aimed properly.
To adjust the vertical aim:
1. Open the hood. See
Hood on
page 10‑5.2. Locate the aim dot on the lens of the low‐beam headlamp.
3. Record the distance from the ground to the aim dot on the
low‐beam headlamp.
Page 494 of 594

Black plate (70,1)GMC Sierra Owner Manual - 2011
10-70 Vehicle Care
For additional information and
details about the DIC operation and
displays, seeDriver Information
Center (DIC) on page 5‑33 and
Tire Messages on page 5‑49.
The low tire pressure warning light
may come on in cool weather when
the vehicle is first started, and then
turn off as the vehicle is driven.
This could be an early indicator that
the air pressure is getting low and
needs to be inflated to the proper
pressure.
A Tire and Loading Information
label shows the size of the original
equipment tires and the correct
inflation pressure for the tires when
they are cold. See Vehicle Load
Limits on page 9‑25, for an example
of the Tire and Loading Information
label and its location. Also see
Tire Pressure on page 10‑66. The TPMS can warn about a
low tire pressure condition but
it does not replace normal tire
maintenance. See
Tire Inspection
on page 10‑73, Tire Rotation on
page 10‑73 andTires on
page 10‑57.
Notice: Tire sealant materials are
not all the same. A non-approved
tire sealant could damage the
TPMS sensors. TPMS sensor
damage caused by using
an incorrect tire sealant is
not covered by the vehicle
warranty. Always use only
the GM-approved tire sealant
available through your dealer
or included in the vehicle.TPMS Malfunction Light and
Message
The TPMS will not function properly
if one or more of the TPMS sensors
are missing or inoperable. When
the system detects a malfunction,
the low tire pressure warning light
flashes for about one minute and
then stays on for the remainder of
the ignition cycle. A DIC warning
message also displays. The
malfunction light and DIC warning
message come on at each ignition
cycle until the problem is corrected.
Some of the conditions that can
cause these to come on are:
.One of the road tires has been
replaced with the spare tire.
The spare tire does not have a
TPMS sensor. The malfunction
light and the DIC message
should go off after the road
tire is replaced and the sensor
matching process is performed
successfully. See "TPMS Sensor
Matching Process" later in this
section.
Page 497 of 594

Black plate (73,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-73
Tire Inspection
We recommend that you
regularly inspect the vehicle's
tires, including the spare tire,
if the vehicle has one, for signs
of wear or damage at least once
a month.
Always remove the tires if any
of the following statements
are true:
.You can see the indicators at
three or more places around
the tire.
.You can see cord or fabric
showing through the tire's
rubber.
.The tread or sidewall is
cracked, cut, or snagged
deep enough to show cord
or fabric.
.The tire has a bump, bulge,
or split.
.The tire has a puncture, cut,
or other damage that cannot
be repaired well because of
the size or location of the
damage.
Tire Rotation
Tires should be rotated every
12 000 km (7,500 miles).
SeeScheduled Maintenance on
page 11‑2.
The purpose of a regular tire
rotation is to achieve a uniform
wear for all tires on the vehicle.
This will ensure that your vehicle
continues to perform most like it
did when the tires were new.
Any time you notice unusual
wear, rotate your tires as soon
as possible and check wheel
alignment. Also check for
damaged tires or wheels. See
When It Is Time for New
Tires on page 10‑76 andWheel
Replacement on page 10‑82.
If your vehicle has dual rear
wheels, also see Dual Tire
Rotation on page 10‑75.
If your vehicle has single rear
wheels and the tread design for
the front tires is the same as
the rear tires, use the rotation
pattern shown here when
rotating the tires.
Page 515 of 594

Black plate (91,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-91
Rear Position–All Other Models
For all other models, position the
jack under the rear axle between
the spring anchor and the shock
absorber bracket.
If you have added a snow plow
to the front of your vehicle, lower
the snow plow fully before
raising the vehicle.
Make sure that the jack head is
positioned so that the rear axle
is resting securely between
the grooves that are on the
jack head.
{WARNING
Getting under a vehicle when it
is jacked up is dangerous. If the
vehicle slips off the jack, you
could be badly injured or killed.
Never get under a vehicle when
it is supported only by a jack.
{WARNING
Raising the vehicle with the
jack improperly positioned can
damage the vehicle and even
make the vehicle fall. To help
avoid personal injury and vehicle
damage, be sure to fit the jack lift
head into the proper location
before raising the vehicle. 6. Turn the wheel wrench
clockwise to raise the vehicle.
Raise the vehicle far enough off
the ground so there is enough
room for the spare tire to fit
under the wheel well.
7. Remove all the wheel nuts andtake off the flat tire.
Page 520 of 594

Black plate (96,1)GMC Sierra Owner Manual - 2011
10-96 Vehicle Care
6. Raise the tire fully against theunderside of the vehicle by
turning the wheel wrench
clockwise until you hear two
clicks or feel it skip twice.
You cannot overtighten the
cable.
7. Make sure the tire is stored
securely. Push, pull (A), and then
try to turn (B) the tire. If the tire
moves, use the wheel wrench
to tighten the cable.
8. Reinstall the spare tire lock, if the vehicle has one. To store the jack and jack tools:
A. Wing Nut Retaining Wheel
Blocks
B. Wheel Blocks
C. Wing Nut Retaining Tool Kit
D. Wheel Wrench and Extensions
E. Tool Bag
F. Jack Mounting Bracket
G. Jack
H. Bolt Retaining Wheel Blocks 1. Put the tools (D) in the tool
bag (E) and place them in the
retaining bracket (C).
2. Tighten down the wing nut (C).
3. Assemble the wheel blocks (B) and jack (G) together with the
wing nut (A) and retaining
bolt (H).
4. Position the jack (G) in the mounting bracket (F). Position
the holes in the base of the
jack (G) onto the pin in the
mounting bracket (F).
5. Return them to their original location in the vehicle. For more
information, refer to “Removing
the Spare Tire and Tools” for
more information.