tire pressure SATURN AURA 2008 User Guide

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.
{CAUTION:
Poorly maintained and improperly used
tires are dangerous.
Overloading your vehicle’s tires can
cause overheating as a result of too
much exing. You could have an
air-out and a serious accident. See
Loading Your Vehicle on page 4-22.
CAUTION: (Continued)
CAUTION: (Continued)

Underinated 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 vehicle’s tires are cold. See
Inflation - Tire Pressure on page 5-52.
Overinated 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 the tire’s tread is badly worn, or
if your vehicle’s tires have been
damaged, replace them.
5-46
ProCarManuals.com

(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, seeUniform Tire Quality
Grading on page 5-62.
(G) Maximum Cold Ination Load Limit
:Maximum load that can be carried and the
maximum pressure needed to support that load.
For information on recommended tire pressure
seeInflation - Tire Pressure on page 5-52
andLoading Your Vehicle on page 4-22.
Tire Size
The following illustration shows, an example of,
a typical passenger car tire size.
(A) Passenger (P-Metric) Tire
:The United States
version of a metric tire sizing system. The letter P
as the rst 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 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.
5-48
ProCarManuals.com

(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
:The service description
indicates the load range and speed rating of a
tire. The load index can range from 1 to 279.
Speed ratings range from A to Z.
Tire Terminology and Denitions
Air Pressure:The amount of air inside the
tire pressing outward on each square inch of
the tire. Air pressure is expressed in pounds
per square inch (psi) or kilopascal (kPa).
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 pounds per square inch
(psi) or kilopascals (kPa) before a tire has built up
heat from driving. SeeInflation - Tire Pressure
on page 5-52.
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.
DOT Markings
:A code molded into the sidewall
of a tire signifying that the tire is in compliance
with the U.S. Department of Transportation (DOT)
motor vehicle safety standards. The DOT code
includes the Tire Identication Number (TIN),
an alphanumeric designator which can also identify
the tire manufacturer, production plant, brand,
and date of production.
5-49
ProCarManuals.com

GVWR:Gross Vehicle Weight Rating.
SeeLoading Your Vehicle on page 4-22.
GAWR FRT
:Gross Axle Weight Rating for the
front axle. SeeLoading Your Vehicle on page 4-22.
GAWR RR
:Gross Axle Weight Rating for the rear
axle. SeeLoading Your Vehicle on page 4-22.
Intended Outboard Sidewall
:The side of
an asymmetrical tire, that must always face
outward when mounted on a vehicle.
Kilopascal (kPa)
:The metric unit for air pressure.
Light Truck (LT-Metric) Tire
:A tire used on
light duty trucks and some multipurpose passenger
vehicles.
Load Index
:An assigned number ranging from
1 to 279 that corresponds to the load carrying
capacity of a tire.
Maximum Ination Pressure
:The maximum
air pressure to which a cold tire can be inated.
The maximum air pressure is molded onto the
sidewall.
Maximum Load Rating
:The load rating for a tire
at the maximum permissible ination pressure
for that tire.Maximum Loaded Vehicle Weight
:The sum of
curb weight, accessory weight, vehicle capacity
weight, and production options weight.
Normal Occupant Weight
:The number of
occupants a vehicle is designed to seat multiplied
by 150 lbs (68 kg). SeeLoading Your Vehicle
on page 4-22.
Occupant Distribution
:Designated seating
positions.
Outward Facing Sidewall
:The side of an
asymmetrical tire that has a particular side that
faces outward when mounted on a vehicle.
The side of the tire that contains a whitewall,
bears white lettering, or bears manufacturer,
brand, and/or model name molding that is higher
or deeper than the same moldings on the
other sidewall of the tire.
Passenger (P-Metric) Tire
:A tire used on
passenger cars and some light duty trucks and
multipurpose vehicles.
Recommended Ination Pressure
:Vehicle
manufacturer’s recommended tire ination
pressure as shown on the tire placard. See
Inflation - Tire Pressure on page 5-52and
Loading Your Vehicle on page 4-22.
5-50
ProCarManuals.com

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 1/16 inch (1.6 mm) of tread
remains. SeeWhen It Is Time for New Tires
on page 5-59.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 5-62.
Vehicle Capacity Weight
:The number of
designated seating positions multiplied by
150 lbs (68 kg) plus the rated cargo load.
SeeLoading Your Vehicle on page 4-22.
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 ination pressure. See “Tire
and Loading Information Label” underLoading
Your Vehicle on page 4-22.
5-51
ProCarManuals.com

Ination - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under-ination or over-ination is all right.
It is not. If your tires do not have enough air
(under-ination), you can get the following:
Too much exing
Too much heat
Tire overloading
Premature or irregular wear
Poor handling
Reduced fuel economy
If your tires have too much air (over-ination),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazardsA vehicle specic Tire and Loading Information
label is attached to your vehicle. This label shows
your vehicle’s original equipment tires and the
correct ination pressures for your tires when they
are cold. The recommended cold tire ination
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,
seeLoading Your Vehicle on page 4-22. 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.
How to Check
Use a good quality pocket-type gage to check
tire pressure. You cannot tell if your tires are
properly inated simply by looking at them.
Radial tires may look properly inated even when
they are under-inated. Check the tire’s ination
pressure when the tires are cold. Cold means your
vehicle has been sitting for at least three hours
or driven no more than 1 mile (1.6 km).
5-52
ProCarManuals.com

Remove the valve cap from the tire valve stem.
Press the tire gage rmly onto the valve to
get a pressure measurement. If the cold tire
ination pressure matches the recommended
pressure on the Tire and Loading Information
label, no further adjustment is necessary.
If the ination pressure is low, add air until you
reach the recommended amount.
If you overll 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 inated to the ination
pressure recommended by the vehicle manufacturer
on the vehicle placard or tire ination pressure label.
(If your vehicle has tires of a different size than the
size indicated on the vehicle placard or tire ination
pressure label, you should determine the proper
tire ination 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 signicantly under-inated.
Accordingly, when the low tire pressure telltale
illuminates, you should stop and check your tires as
soon as possible, and inate them to the proper
pressure. Driving on a signicantly under-inated tire
causes the tire to overheat and can lead to tire failure.
Under-ination also reduces fuel efficiency and tire
tread life, and may affect the vehicle’s handling
and stopping ability.
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-ination
has not reached the level to trigger illumination of
the TPMS low tire pressure telltale.
5-53
ProCarManuals.com

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
ash 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.
SeeTire Pressure Monitor Operation on page 5-55, for
additional information.Federal Communications
Commission (FCC) and Industry
and Science Canada
The Tire Pressure Monitor System (TPMS) operates
on a radio frequency and complies with Part 15 of
the FCC Rules. Operation is subject to the following
two conditions:
1. This device may not cause harmful interference.
2. This device must accept any interference received,
including interference that may cause undesired
operation.
The Tire Pressure Monitor System (TPMS) operates
on a radio frequency and complies with RSS-210
of Industry and Science Canada. Operation is subject
to the following two conditions:
1. This device may not cause interference.
2. This device must accept any interference received,
including interference that may cause undesired
operation of the device.
Changes or modications to this system by other than
an authorized service facility could void authorization to
use this equipment.
5-54
ProCarManuals.com

Tire Pressure Monitor Operation
The Tire Pressure Monitor System (TPMS) is designed
to warn the driver when a low tire pressure condition
exists. TPMS sensors are mounted onto each tire and
wheel assembly. 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 turns on the low
tire pressure warning light
located on the instrument
panel cluster.
At the same time a message to check the pressure in a
specic tire appears on the Driver Information Center
(DIC) display. The low tire pressure warning light
and the DIC warning message come on at each ignition
cycle until the tires are inated to the correct ination
pressure. Using the DIC, tire pressure levels can
be viewed by the driver.For additional information and details about the DIC
operation and displays seeDIC Operation and Displays
on page 3-44andDIC Warnings and Messages on
page 3-46.
The low tire pressure warning light may come on in
cool weather when the vehicle is rst started, and then
turn off as you start to drive. This could be an early
indicator that the air pressure in the tire(s) are getting
low and need to be inated to the proper pressure.
A Tire and Loading Information label shows the size of
your vehicle’s original equipment tires and the correct
ination pressure for your vehicle’s tires when they are
cold. SeeLoading Your Vehicle on page 4-22, for an
example of the Tire and Loading Information label and
its location on your vehicle. Also seeInflation - Tire
Pressure on page 5-52.
Your vehicle’s TPMS system can warn you about a low
tire pressure condition but it does not replace normal
tire maintenance. SeeTire Inspection and Rotation
on page 5-58andTires on page 5-46.
Notice:Using non-approved tire sealants could
damage the Tire Pressure Monitor System (TPMS)
sensors. TPMS sensor damage caused by using
an incorrect tire sealant is not covered by the
vehicle warranty. Always use the GM approved tire
sealant available through your dealer/retailer.
5-55
ProCarManuals.com

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 warning light
ashes for about one minute and then stays on for the
remainder of the ignition cycle. A DIC warning message is
also displayed. The low tire warning light and DIC warning
message come on at each ignition cycle until the problem
is corrected. Some of the conditions that can cause the
malfunction light and DIC message to come on are:
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 your
vehicle’s original equipment tires or wheels. Tires
and wheels other than those recommended for your
vehicle could prevent the TPMS from functioning
properly. SeeBuying New Tires on page 5-60.
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 identication code.
Any time you replace one or more of the TPMS sensors
or rotate the vehicle’s tires, the identication codes
need to be matched to the new tire/wheel location.
The sensors are matched, to the tire/wheel locations,
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. When increasing the tire’s pressure,
do not exceed the maximum ination pressure
indicated on the tire’s sidewall. To decrease the tire’s
air-pressure use the pointed end of the valve cap,
a pencil-style air pressure gage, or a key.
5-56
ProCarManuals.com