Vehicle Care 10-23
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 inCapacities and
Specifications on page 12‑2.
Brake linings should always be
replaced as complete axle sets.
Brake Pedal Travel
See your dealer/retailer 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.
Brake Fluid
The brake master cylinder reservoir
is filled with DOT 3 brake fluid as
indicated on the reservoir cap. See
Engine Compartment Overview
on
page 10‑6for the location of the
reservoir.
There are only two reasons why the
brake fluid level in the reservoir
might go down:
.The brake fluid level goes down
because of normal brake lining
wear. When new linings are
installed, the fluid level goes
back up.
Vehicle Care 10-37
RelaysUsage
DRL2 Daytime Running
Lamps 2 Relay
LT/UNLCK Driver Side Unlock
Relay
DRL Daytime Running
Lamps Relay
SPARE Spare
FRT/WSW Front Windshield
Washer RelayWheels 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. See
Vehicle
Load Limits on page 9‑12.
(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 10‑44.
.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.
10-38 Vehicle Care
Tire Sidewall Labeling
Useful information about a tire is
molded into its sidewall. The
examples below show a typical
passenger vehicle tire and a
compact spare tire sidewall.
Passenger (P-Metric) Tire Example
(A) Tire Size:The tire size 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.
(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 the DOT (Department
of Transportation) code is 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 10‑54.
10-40 Vehicle Care
(F) Tire Size:A combination of
letters and numbers define a
tire's width, height, aspect ratio,
construction type, and service
description. The letter T as the
first character in the tire size
means the tire is for temporary
use only.
(G) 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.
Tire Designations
Tire Size
The following illustration shows
an example of a typical
passenger vehicle tire size.
(A) Passenger (P-Metric) Tire:
The United States version of a
metric tire sizing system. The
letter P as the first character in
the tire size means a passenger
vehicle 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 60, as shown in
item C of the illustration, it would
mean that the tire's sidewall is
60 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.
Vehicle Care 10-43
Passenger (P-Metric) Tire:A
tire used on passenger cars and
some light duty trucks and
multipurpose vehicles.
Recommended Inflation
Pressure
:Vehicle
manufacturer's recommended
tire inflation pressure as shown
on the tire placard. See Tire
Pressure
on page 10‑44and
Vehicle Load Limits
on
page 9‑12
.
Radial Ply Tire
:A pneumatic
tire in which the ply cords that
extend to the beads are laid at
90 degrees to the centerline of
the tread.
Rim
:A metal support for a tire
and upon which the tire beads
are seated.
Sidewall
:The portion of a tire
between the tread and the bead. Speed Rating
:An
alphanumeric code assigned to
a tire indicating the maximum
speed at which a tire can
operate.
Traction
:The friction between
the tire and the road surface.
The amount of grip provided.
Tread
:The portion of a tire that
comes into contact with
the road.
Treadwear Indicators
:Narrow
bands, sometimes called wear
bars, that show across the tread
of a tire when only 1.6 mm
(1/16 inch) of tread remains.
See When It Is Time for New
Tires
on page 10‑51.
UTQGS (Uniform Tire Quality
Grading Standards)
:A tire
information system that provides
consumers with ratings for a
tire's traction, temperature,
and treadwear. Ratings are determined by tire
manufacturers using
government testing procedures.
The ratings are molded into the
sidewall of the tire. See
Uniform
Tire Quality Grading
on
page 10‑54
.
Vehicle Capacity Weight
:The
number of designated seating
positions multiplied by
68 kg (150 lbs) plus the rated
cargo load. See Vehicle Load
Limits
on page 9‑12.
Vehicle Maximum Load on the
Tire
:Load on an individual tire
due to curb weight, accessory
weight, occupant weight, and
cargo weight.
Vehicle Placard
:A label
permanently attached to a
vehicle showing the vehicle's
capacity weight and the original
equipment tire size and
recommended inflation pressure.
10-44 Vehicle Care
See“Tire and Loading
Information Label” underVehicle
Load Limits
on page 9‑12.
Tire Pressure
Tires need the correct amount
of air pressure to operate
effectively.
Notice:Do not let anyone tell
you that under-inflation or
over-inflation is all right. It is
not. If your tires do not have
enough air (under-inflation),
you can get the following:
.Too much flexing
.Too much heat
.Tire overloading
.Premature or
irregular wear
.Poor handling
.Reduced fuel economy If your tires have too much air
(over-inflation), you can get
the following:
.Unusual wear
.Poor handling
.Rough ride
.Needless damage from
road hazards
A vehicle specific Tire and
Loading Information label is
attached to your vehicle. This
label shows your vehicle's
original equipment tires and the
correct inflation pressures for
your tires when they are cold.
The recommended cold tire
inflation pressure, shown on the
label, is the minimum amount of
air pressure needed to support
your vehicle's maximum load
carrying capacity. For additional information
regarding how much weight your
vehicle can carry, and an
example of the Tire and Loading
Information label, see
Vehicle
Load Limits
on page 9‑12. How
you load your vehicle affects
vehicle handling and ride
comfort. Never load your vehicle
with more weight than it was
designed to carry.
When to Check
Check your tires once a month
or more. Do not forget to check
the compact spare tire, if the
vehicle has one. The compact
spare should be at 60 psi
(420 kPa). For additional
information regarding the
compact spare tire, see
Compact Spare Tire
on
page 10‑80
.
Vehicle Care 10-45
How to Check
Use a good quality pocket-type
gage to check tire pressure.
You cannot tell if your tires are
properly inflated simply by
looking at them. Radial tires may
look properly inflated even when
they are under-inflated. Check
the tire's inflation pressure when
the tires are cold. Cold means
your vehicle has been sitting for
at least three hours or driven no
more than 1.6 km (1 mile).
Remove the valve cap from the
tire valve stem. Press the tire
gage firmly onto the valve to get
a pressure measurement. If the
cold tire inflation pressure
matches the recommended
pressure on the Tire and
Loading Information label, no
further adjustment is necessary.
If the inflation pressure is low,
add air until you reach the
recommended amount.If you overfill the tire, release air
by pushing on the metal stem in
the center of the tire valve.
Re-check the tire pressure with
the tire gage.
Be sure to put the valve caps
back on the valve stems. They
help prevent leaks by keeping
out dirt and moisture.
Tire Pressure Monitor
System
The Tire Pressure Monitor System
(TPMS) uses radio and sensor
technology to check tire pressure
levels. The TPMS sensors monitor
the air pressure in your vehicle's
tires and transmit tire pressure
readings to a receiver located in the
vehicle.
Each tire, including the spare
(if provided), should be checked
monthly when cold and inflated to
the inflation pressure recommended
by the vehicle manufacturer on the
vehicle placard or tire inflation pressure label. (If your vehicle has
tires of a different size than the size
indicated on the vehicle placard or
tire inflation pressure label, you
should determine the proper tire
inflation pressure for those tires.)
As an added safety feature, your
vehicle has been equipped with a
tire pressure monitoring system
(TPMS) that illuminates a low tire
pressure telltale when one or more
of your tires is significantly
under-inflated.
Accordingly, when the low tire
pressure telltale illuminates, you
should stop and check your tires as
soon as possible, and inflate them
to the proper pressure. Driving on a
significantly under-inflated tire
causes the tire to overheat and can
lead to tire failure. Under-inflation
also reduces fuel efficiency and tire
tread life, and may affect the
vehicle's handling and stopping
ability.
10-46 Vehicle Care
Please note that the TPMS is
not a substitute for proper tire
maintenance, and it is the driver's
responsibility to maintain correct tire
pressure, even if under-inflation has
not reached the level to trigger
illumination of the TPMS low tire
pressure telltale.
Your vehicle has also been
equipped with a TPMS malfunction
indicator to indicate when the
system is not operating properly.
The TPMS malfunction indicator is
combined with the low tire pressure
telltale. When the system detects a
malfunction, the telltale will flash for
approximately one minute and then
remain continuously illuminated.
This sequence will continue upon
subsequent vehicle start-ups as
long as the malfunction exists.
When the malfunction indicator is
illuminated, the system may not
be able to detect or signal low
tire pressure as intended.TPMS malfunctions may occur for a
variety of reasons, including the
installation of replacement or
alternate tires or wheels on the
vehicle that prevent the TPMS from
functioning properly. Always check
the TPMS malfunction telltale after
replacing one or more tires or
wheels on your vehicle to ensure
that the replacement or alternate
tires and wheels allow the TPMS to
continue to function properly.
See
Tire Pressure Monitor
Operation
on page 10‑46for
additional information.
Federal Communications
Commission (FCC) and
Industry and Science Canada
See Radio Frequency Statementon
page 13‑16for information
regarding Part 15 of the Federal
Communications Commission (FCC)
Rules and RSS-210/211 of Industry
and Science Canada.
Tire Pressure Monitor
Operation
This vehicle may have a Tire
Pressure Monitor System (TPMS).
The TPMS is designed to warn the
driver when a low tire pressure
condition exists. TPMS sensors are
mounted onto each tire and wheel
assembly, excluding the spare tire
and wheel assembly, if the vehicle
has one. The TPMS sensors
monitor the air pressure in the
vehicle's tires and transmits the tire
pressure readings to a receiver
located in the vehicle.
When a low tire pressure condition
is detected, the TPMS illuminates
the low tire pressure warning light
located on the instrument panel
cluster.