service HUMMER H3 2010 Repair Manual

10-26 Vehicle Care
Brakes
This vehicle has disc brakes. Disc
brake pads have built-in wear
indicators that make a high-pitched
warning sound when the brake pads
are worn and new pads are needed.
The sound can come and go or be
heard all the time the vehicle is
moving, except when applying the
brake pedal firmly.
{WARNING
The brake wear warning sound
means that soon the brakes will
not work well. That could lead to
an accident. When the brake
wear warning sound is heard,
have the vehicle serviced.
Notice: Continuing to drive with
worn-out brake pads could result
in costly brake repair. Some driving conditions or climates
can cause a brake squeal when the
brakes are first applied or lightly
applied. This does not mean
something is wrong with the brakes.
Properly torqued wheel nuts are
necessary to help prevent brake
pulsation. When tires are rotated,
inspect brake pads for wear and
evenly tighten wheel nuts in the
proper sequence to torque
specifications in
Capacities and
Specifications on page 12‑2.
Brake linings should always be
replaced as complete axle sets.
Brake Pedal Travel
See your dealer if the brake pedal
does not return to normal height,
or if there is a rapid increase in
pedal travel. This could be a sign
that brake service might be
required.
Brake Adjustment
Every time the brakes are applied,
with or without the vehicle moving,
the brakes adjust for wear.
Replacing Brake System Parts
The braking system on a vehicle is
complex. Its many parts have to be
of top quality and work well together
if the vehicle is to have really good
braking. The vehicle was designed
and tested with top-quality brake
parts. When parts of the braking
system are replaced, be sure to get
new, approved replacement parts.
If this is not done, the brakes might
not work properly. For example,
installing disc brake pads that are
wrong for the vehicle, can change
the balance between the front and
rear brakes —for the worse. The
braking performance expected can
change in many other ways if the
wrong replacement brake parts are
installed.

10-30 Vehicle Care
Starter Switch Check
{WARNING
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle.
2. Firmly apply both the parking brake and the regular brake.
See Parking Brake
on
page 9‑51.
Do not use the accelerator
pedal, and be ready to turn off
the engine immediately if it
starts. 3. For automatic transmission
vehicles, try to start the engine
in each gear. The vehicle
should start only in P (Park) or
N (Neutral). If the vehicle starts
in any other position, contact
your dealer for service.
For manual transmission
vehicles, put the shift lever in
Neutral, push the clutch pedal
down halfway, and try to start
the engine. The vehicle should
start only when the clutch pedal
is pushed down all the way to
the floor. If the vehicle starts
when the clutch pedal is not
pushed all the way down,
contact your dealer for service.
Automatic Transmission
Shift Lock Control
System Check
{WARNING
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Firmly apply the parking brake. See Parking Brake
on
page 9‑51.
Be ready to apply the regular
brake immediately if the vehicle
begins to move.

Vehicle Care 10-31
3. With the engine off, turn theignition to ON/RUN, but do
not start the engine. Without
applying the regular brake, try
to move the shift lever out of
P (Park) with normal effort. If the
shift lever moves out of P (Park),
contact your dealer for service.
Ignition Transmission
Lock Check
While parked, and with the parking
brake set, try to turn the ignition to
LOCK/OFF in each shift lever
position.
.For automatic transmission
vehicles, the ignition should turn
to LOCK/OFF only when the
shift lever is in P (Park). The
ignition key should come out
only in LOCK/OFF.
.For manual transmission
vehicles, the ignition key should
come out only in LOCK/OFF.
Contact your dealer if service is
required.
Park Brake and P (Park)
Mechanism Check
{WARNING
When you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move. Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake.
.To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot
pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.
.To check the P (Park)
mechanism's holding ability:
With the engine running, shift
to P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.

Vehicle Care 10-33
Headlamp Aiming
The vehicle may have a visual
optical headlamp aiming system.
The aim has been preset at the
factory and should need no further
adjustment.
However, if the vehicle is damaged
in a crash, the headlamp aim may
be affected and adjustment may be
necessary.
If oncoming vehicles flash their high
beams at you, this may also mean
the vertical aim needs to be
adjusted.
It is recommended that the vehicle
is taken to your dealer for service if
the headlamps need to be re-aimed.
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 or other flat surface.
.On a level surface which is level
all the way to a wall.
.Placed so it is at a right angle to
the wall or other flat surface.
.Clear of any snow, ice, or mud
on it.
.Fully assembled, the tires
properly inflated, and all other
work stopped while headlamp
aiming is being performed.
.Normally loaded with the spare
tire in its original location and a
full tank of fuel and one person
or 75 kg (160 lbs) sitting on the
driver seat.To adjust the vertical aim:
1. Open the hood. See
Hood
on
page 10‑5.
2. Record the distance from the ground to the aim dot on the
headlamp.

10-44 Vehicle Care
Wheels and Tires
Tires
Your new vehicle comes with
high-quality tires made by a
leading tire manufacturer. If you
ever have questions about your
tire warranty and where to
obtain service, see your vehicle
Warranty booklet for details. For
additional information refer to
the tire manufacturer.
{WARNING
Poorly maintained and improperly
used tires are dangerous.
.Overloading your tires can
cause overheating as a result
of too much flexing. You
could have an air-out and a
serious accident. SeeVehicle
Load Limits on page 9‑27.
(Continued)
WARNING (Continued)
.Underinflated tires pose the
same danger as overloaded
tires. The resulting accident
could cause serious injury.
Check all tires frequently to
maintain the recommended
pressure. Tire pressure
should be checked when your
tires are cold. See Tire
Pressure on page 10‑51.
.Overinflated tires are more
likely to be cut, punctured
or broken by a sudden
impact —such as when you
hit a pothole. Keep tires at
the recommended pressure.
.Worn, old tires can cause
accidents. If your tread is
badly worn, or if your tires
have been damaged,
replace them.
Tire Sidewall Labeling
Useful information about a tire
is molded into the sidewall.
The following illustrations are
examples of a typical P‐Metric
and a LT‐Metric tire sidewall.
Passenger (P‐Metric) Tire
(A) Tire Size:The tire size
code is a combination of letters
and numbers used to define a
particular tire's width, height,
aspect ratio, construction type,

Vehicle Care 10-45
and service description. See the
“Tire Size”illustration later in this
section for more detail.
(B) TPC Spec (Tire
Performance Criteria
Specification)
:Original
equipment tires designed to
GM's specific tire performance
criteria have a TPC specification
code molded onto the sidewall.
GM's TPC specifications meet
or exceed all federal safety
guidelines.
(C) DOT (Department of
Transportation)
:The
Department of Transportation
(DOT) code indicates that
the tire is in compliance with
the U.S. Department of
Transportation Motor Vehicle
Safety Standards.
(D) Tire Identification Number
(TIN)
:The letters and numbers
following DOT code are the Tire
Identification Number (TIN). The TIN shows the
manufacturer and plant code,
tire size, and date the tire
was manufactured. The TIN is
molded onto both sides of the
tire, although only one side may
have the date of manufacture.
(E) Tire Ply Material
:The type
of cord and number of plies in
the sidewall and under the tread.
(F) Uniform Tire Quality
Grading (UTQG)
:Tire
manufacturers are required
to grade tires based on
three performance factors:
treadwear, traction, and
temperature resistance.
For more information, see
Uniform Tire Quality Grading
on
page 10‑61
.
(G) Maximum Cold Inflation
Load Limit
:Maximum load
that can be carried and the
maximum pressure needed
to support that load. For information on
recommended tire pressure
see
Tire Pressure
on page 10‑51
and Vehicle Load Limitson
page 9‑27
.
Light Truck (LT-Metric) Tire
(A) Tire Size:The tire size
code is a combination of letters
and numbers used to define a
particular tire's width, height,
aspect ratio, construction type,
and service description. See the
“Tire Size” illustration later in this
section for more detail.

Vehicle Care 10-47
(B) Tire Width:The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(C) Aspect Ratio
:A two‐digit
number that indicates the tire
height‐to‐width measurements.
For example, if the tire size
aspect ratio is 75, as shown in
item C of the illustration, it would
mean that the tire's sidewall is
75 percent as high as it is wide.
(D) Construction Code
:
A letter code is used to indicate
the type of ply construction in
the tire. The letter R means
radial ply construction; the
letter D means diagonal or
bias ply construction; and the
letter B means belted‐bias ply
construction.
(E) Rim Diameter
:Diameter of
the wheel in inches. (F) Service Description
:These
characters represent the load
index and speed rating of the
tire. The load index represents
the load carry capacity a tire is
certified to carry. The speed
rating is the maximum speed a
tire is certified to carry a load.
Light Truck (LT‐Metric) Tire
(A) Light Truck (LT‐Metric)
Tire
:The United States
version of a metric tire sizing
system. The letters LT as the
first two characters in the tire
size means a light truck tire
engineered to standards set
by the U.S. Tire and Rim
Association. (B) Tire Width
:The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(C) Aspect Ratio
:A two‐digit
number that indicates the tire
height‐to‐width measurements.
For example, if the tire size
aspect ratio is 75, as shown
in item C of the light truck
(LT‐Metric) tire illustration, it
would mean that the tire's
sidewall is 75 percent as high
as it is wide.
(D) Construction Code
:
A letter code is used to indicate
the type of ply construction in
the tire. The letter R means
radial ply construction; the
letter D means diagonal or
bias ply construction; and the
letter B means belted‐bias ply
construction.

10-48 Vehicle Care
(E) Rim Diameter:Diameter of
the wheel in inches.
(F) Load Range
:Load Range.
(G) Service Description
:The
service description indicates the
load index and speed rating of a
tire. If two numbers are given as
in the example, 120/116, then
this represents the load index for
single versus dual wheel usage
(single/dual). The speed rating is
the maximum speed a tire is
certified to carry a load.
Tire Terminology and
Definitions
Air Pressure:The amount
of air inside the tire pressing
outward on each square inch
of the tire. Air pressure is
expressed in psi (pounds per
square inch) or kPa (kilopascal). Accessory Weight
:This
means the combined weight
of optional accessories.
Some examples of optional
accessories are, automatic
transmission, power steering,
power brakes, power windows,
power seats, and air
conditioning.
Aspect Ratio
:The relationship
of a tire's height to its width.
Belt
:A rubber coated layer of
cords that is located between
the plies and the tread. Cords
may be made from steel or other
reinforcing materials.
Bead
:The tire bead contains
steel wires wrapped by steel
cords that hold the tire onto
the rim. Bias Ply Tire
:A pneumatic tire
in which the plies are laid at
alternate angles less than
90 degrees to the centerline of
the tread.
Cold Tire Pressure
:The
amount of air pressure in a tire,
measured in psi (pounds per
square inch) or kPa (kilopascal)
before a tire has built up heat
from driving. See Tire Pressure
on page 10‑51.
Curb Weight
:The weight of a
motor vehicle with standard and
optional equipment including
the maximum capacity of fuel,
oil, and coolant, but without
passengers and cargo.

Vehicle Care 10-55
.The TPMS sensor matching
process was started but not
completed or not completed
successfully after rotating the
vehicle's tires. The DIC message
and TPMS malfunction light
should go off once the TPMS
sensor matching process is
performed successfully. See
“TPMS Sensor Matching
Process”later in this section.
.One or more TPMS sensors
are missing or damaged. The
DIC message and the TPMS
malfunction light should go
off when the TPMS sensors
are installed and the sensor
matching process is performed
successfully. See your
dealer/retailer for service.
.Replacement tires or wheels do
not match the vehicle's original
equipment tires or wheels. Tires
and wheels other than those
recommended for the vehicle
could prevent the TPMS from
functioning properly. See Buying
New Tires on page 10‑59.
.Operating electronic devices or
being near facilities using radio
wave frequencies similar to the
TPMS could cause the TPMS
sensors to malfunction.
If the TPMS is not functioning it
cannot detect or signal a low tire
condition. See your dealer/retailer
for service if the TPMS malfunction
light and DIC message comes on
and stays on.
TPMS Sensor Matching
Process
Each TPMS sensor has a unique
identification code. Any time you
replace one or more of the TPMS
sensors or rotate the vehicle's tires,
the identification codes need to
be matched to the new tire/wheel
position. The sensors are matched
to the tire/wheel positions in the
following order: driver side front tire,
passenger side front tire, passenger
side rear tire, and driver side rear
tire using a TPMS diagnostic tool.
See your dealer/retailer for service.
The TPMS sensors can also be
matched to each tire/wheel position
by increasing or decreasing the
tire's air pressure. If increasing the
tire's air pressure, do not exceed
the maximum inflation pressure
indicated on the tire's sidewall.
To let air-pressure out of a tire you
can use the pointed end of the valve
cap, a pencil-style air pressure
gauge, or a key.

10-62 Vehicle Care
For example, a tire graded 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.
The grade C corresponds to a
level of performance which all
passenger car tires must meet
under the Federal Motor Safety Standard No. 109. Grades B
and A represent higher levels of
performance on the laboratory
test wheel than the minimum
required by law. Warning: The
temperature grade for this tire is
established for a tire that is
properly inflated and not
overloaded. Excessive speed,
underinflation, or excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure.
Wheel Alignment and Tire
Balance
The tires and wheels on the vehicle
were aligned and balanced carefully
at the factory to give the longest tire
life and best overall performance.
Adjustments to wheel alignment and
tire balancing will not be necessary
on a regular basis. However, if there
is unusual tire wear or the vehicle
pulls to one side or the other, the
alignment should be checked.