CHEVROLET COBALT 2008 1.G Owners Manual

(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.
(E) Rim Diameter
:Diameter of the wheel
in inches.
(F) Service Description
:These characters
represent the load range and speed rating of
the tire. The load index represents the load carry
capacity a tire is certied to carry. The load
index can range from 1 to 279. The speed
rating is the maximum speed a tire is certied to
carry a load. 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 5-56.
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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.
GVWR
:Gross Vehicle Weight Rating.
SeeLoading Your Vehicle on page 4-27.
GAWR FRT
:Gross Axle Weight Rating for
the front axle. SeeLoading Your Vehicle
on page 4-27.
GAWR RR
:Gross Axle Weight Rating for the rear
axle. SeeLoading Your Vehicle on page 4-27.
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 4-27.
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.
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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 5-56and
Loading Your Vehicle on page 4-27.
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 5-65.
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 5-68.
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 4-27.
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” under
Loading Your Vehicle on page 4-27.
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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 4-27.
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, it should
be at 60 psi (420 kPa). For additional information
regarding the compact spare tire, seeCompact
Spare Tire on page 5-94.
5-56

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).
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.
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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.
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 5-59for
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.
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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, excluding the spare 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 thecorrect 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 3-40
andDIC Warnings and Messages on page 3-43.
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 4-27, for an
example of the Tire and Loading Information label and
its location on your vehicle. Also seeInflation - Tire
Pressure on page 5-56.
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 5-63andTires on page 5-49.
Notice:Liquid tire sealants could damage the
Tire Pressure Monitor System (TPMS) sensors.
Sensor damage caused by using a tire sealant
is not covered by your warranty. Do not use
liquid tire sealants.
5-59

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:
One of the road tires has been replaced with
the spare tire. The spare tire does not have a
TPMS sensor. The TPMS malfunction light and
DIC message should go off once you re-install
the road tire containing the TPMS sensor.
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 5-66.
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.
5-60

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.
You have two minutes to match each tire and wheel
position. If it takes longer than two minutes to match
any tire and wheel position, the matching process
stops and you need to start over.
TPMS Matching Process for Vehicles
with Remote Keyless Entry (RKE)
1. Set the parking brake.
2. Turn the ignition switch to ON/RUN with the
engine off.
3. Press and hold the Remote Keyless Entry (RKE)
transmitter’s LOCK and UNLOCK buttons, at the
same time, for about ve seconds to start the TPMS
learn mode. The horn sounds twice indicating the
TPMS receiver is ready and in learn mode.
4. Start with the driver side front tire. The driver side
front turn signal also comes on to indicate that
corner’s sensor is ready to be learned.
5. Remove the valve cap from the tire’s valve stem.
Activate the TPMS sensor by increasing or
decreasing the tire’s air pressure for about
eight seconds. The horn chirp, can take up to
30 seconds to sound. It chirps one time and then all
the turn signals ash one time to conrm the
sensor identication code has been matched to the
tire/wheel position.
6. The passenger side front turn signal comes on to
indicate that corner sensor is ready to be learned.
Proceed to the passenger side front tire and
repeat the procedure in Step 5.
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7. The passenger side rear turn signal comes on to
indicate that corner sensor is ready to be learned.
Proceed to the passenger side rear tire and
repeat the procedure in Step 5.
8. The driver side rear turn signal comes on to
indicate that corner sensor is ready to be learned.
Proceed to the driver side rear tire, and repeat
the procedure in Step 5.
9. After hearing the single horn chirp for the driver
side rear tire, two additional horn chirps sound
to indicate the tire learning process is done.
Turn the ignition switch to LOCK/OFF.
If no tires are learned after entering the TPMS
learn mode, or if communication with the receiver
stops, or if the time limit has expired, turn the
ignition switch to LOCK/OFF and start over
beginning with Step 2.
10. Set all four tires to the recommended air pressure
level as indicated on the Tire and Loading
Information label.
11. Put the valve caps back on the valve stems.TPMS Matching Process for Vehicles
without Remote Keyless Entry (RKE)
1. Set the parking brake.
2. Turn the ignition switch to ON/RUN with the
engine off.
3. Using the Driver Information Center (DIC), press
the INFO and Set/Reset buttons at the same time
for about one second. Then press and release
the INFO button until the TIRE LEARN? message
displays.
4. Press and hold the Set/Reset DIC button for
approximately three seconds to start the TPMS
learn mode. The horn sounds twice to indicate the
TPMS receiver is ready and the TIRE LEARN
ON message displays. The driver side front turn
signal also comes on to indicate that corner sensor
is ready to be learned.
5. Start with the driver side front tire.
6. Remove the valve cap from the tire’s valve stem.
Activate the TPMS sensor by increasing or
decreasing the tire’s air pressure for about
eight seconds. The horn chirp, can take up to
30 seconds to sound. It chirps one time and then all
the turn signals ash one time to conrm the sensor
identication code has been matched to the tire/
wheel position.
5-62