1999 PONTIAC GRAND AM Owners Manual

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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 Pontiac Warranty booklet for details.
CAUTION:
Poorly maintained and improperly used tires
are dangerous.

Overloading your tires can cause
overheating as a result of too much friction.
You could have an air
-out and a serious
accident. See ªLoading Your Vehicleº in
the Index.
CAUTION: (Continued)
CAUTION: (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.

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.
Inflation -- Tire Pressure
The Tire-Loading Information label, which is on
the rear edge of the driver's door, shows the correct
inflation pressures for your tires when they're cold.
ªColdº means your vehicle has been sitting for at least
three hours or driven no more than 1 mile (1.6 km).

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NOTICE:
Don't let anyone tell you that underinflation or
overinflation is all right. It's not. If your tires
don't have enough air (underinflation), you can
get the following:

Too much flexing

Too much heat

Tire overloading

Bad wear

Bad handling

Bad fuel economy.
If your tires have too much air (overinflation),
you can get the following:

Unusual wear

Bad handling

Rough ride

Needless damage from road hazards.
When to Check
Check your tires once a month or more.
Don't forget your compact spare tire. It should be
at 60 psi (420 kPa).
How to Check
Use a good quality pocket
-type gage to check tire
pressure. You can't tell if your tires are properly inflated
simply by looking at them. Radial tires may look
properly inflated even when they're underinflated.
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 (If Equipped)
The tire pressure monitor system can alert you to a large
change in the pressure of one tire. The system ªlearnsº
the pressure at each tire throughout the operating speed
range of your vehicle. The system normally takes
between 45 and 90 minutes of driving to learn the tire
pressures. This time may be longer depending on your
individual driving habits. Learning need not be
accumulated during a single trip. Once learned, the
system will remember the tire pressures until the system
is recalibrated.

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After the system has learned tire pressures with properly
inflated tires, the CHECK TIRE PRESSURE light will
come on if the pressure in one tire becomes 12 psi
(83 kPa) lower than the other three tires. The tire pressure
monitor system won't alert you if the pressure in more
than one tire is low, if the system is not properly
calibrated, or if the vehicle is moving at less than 15 mph
(25 km/h), faster than 75 mph (120 km/h), on rough
roads or during turns. The light may also come on if you
are driving on partially cleared pavement.
The tire pressure monitor system detects differences in tire
rotation speeds that are caused by changes in tire pressure.
The system can alert you about a low tire
-- but it doesn't
replace normal tire maintenance. See ªTiresº in the Index.
If the anti
-lock brake system warning light comes on,
the tire pressure monitor system may not be working.
See your dealer for service. (Also, see ªAnti
-Lock
Brake System Warning Lightº in the Index).When the CHECK TIRE PRESSURE light comes on,
you should stop as soon as you can and check all your
tires for damage. (If a tire is flat, see ªIf a Tire Goes
Flatº in the Index.) Also check the tire pressure in all
four tires as soon as you can. See ªInflation
- Tire
Pressureº in the Index.
The light will come on and stay on until you turn off the
ignition or press the RESET button.
Don't reset the tire pressure monitor system without first
correcting the cause of the problem and checking and
adjusting the pressure in all four tires. If you reset the
system when the tire pressures are incorrect, the system
will not work properly and may not alert you when
a tire is low.

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Any time you adjust a tire's pressure, rotate your tires, or
have one or more tires repaired or replaced, you'll need to
reset (calibrate) the tire pressure monitor system. You'll
also need to reset the system whenever you buy new tires
and whenever the vehicle's battery has been disconnected.
To reset (calibrate) the system: turn the ignition switch
to ON (engine not running). The RESET button is
located inside of the driver's side instrument fuse panel.
Press and release the RESET button. The CHANGE
OIL light will begin to flash. Press and release the
RESET button again. The CHANGE OIL light will go
off, and the CHECK TIRE PRESSURE light will start
flashing. When the CHECK TIRE PRESSURE light is
flashing, press and hold the RESET button until the
chime sounds. If the CHECK TIRE PRESSURE light
doesn't go off then, see your dealer for service.
The system completes the calibration process
during driving.The system normally takes 15 to 20 minutes of driving
in each of three speed ranges to ªlearnº tire pressures.
The speed ranges are 15 to 40 mph (25 to 65 km/h),
40 to 65 mph (65 to 105 km/h) and above 65 mph
(105 km/h). When learning is complete, the system will
alert you after 2
-8 minutes if a tire is 12 psi (83 kPa)
different from the other three tires. Detection thresholds
may be higher and detection times may be longer on
rough roads, curves and at high speeds. The system
is not capable of detection at speeds greater than
75 mph (120 km/h).
Tire Inspection and Rotation
Tires should be rotated every 6,000 to 8,000 miles
(10 000 to 13 000 km). 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 ªWhen It's Time for New Tiresº and
ªWheel Replacementº later in this section for
more information.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The first
rotation is the most important. See ªScheduled
Maintenance Servicesº in the Index for scheduled
rotation intervals.

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When rotating your tires, always use the correct rotation
pattern shown here.
Don't include the compact spare tire in your tire rotation.
After the tires have been rotated, adjust the front and
rear inflation pressures as shown on the Tire
-Loading
Information label. Make certain that all wheel nuts are
properly tightened. See ªWheel Nut Torqueº in the Index.
CAUTION:
Rust or dirt on a wheel, or on the parts to which
it is fastened, can make wheel nuts become loose
after a time. The wheel could come off and cause
an accident. When you change a wheel, remove
any rust or dirt from places where the wheel
attaches to the vehicle. In an emergency, you can
use a cloth or a paper towel to do this; but be
sure to use a scraper or wire brush later, if
you need to, to get all the rust or dirt off.
(See ªChanging a Flat Tireº in the Index.)

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When It's Time for New Tires
One way to tell when it's
time for new tires is to
check the treadwear
indicators, which will
appear when your tires have
only 1/16 inch (1.6 mm) or
less of tread remaining.
You need a new tire 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
can't be repaired well because of the size or location
of the damage.
Buying New Tires
To find out what kind and size of tires you need, look at
the Tire
-Loading Information label.
The tires installed on your vehicle when it was new had
a Tire Performance Criteria Specification (TPC Spec)
number on each tire's sidewall. When you get new tires,
get ones with that same TPC Spec number. That way
your vehicle will continue to have tires that are designed
to give proper endurance, handling, speed rating,
traction, ride and other things during normal service on
your vehicle. If your tires have an all
-season tread
design, the TPC number will be followed by an ªMSº
(for mud and snow).
If you ever replace your tires with those not having a
TPC Spec number, make sure they are the same size,
load range, speed rating and construction type (bias,
bias
-belted or radial) as your original tires.

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CAUTION:
Mixing tires could cause you to lose control while
driving. If you mix tires of different sizes or types
(radial and bias
-belted tires), the vehicle may not
handle properly, and you could have a crash.
Using tires of different sizes may also cause
damage to your vehicle. Be sure to use the same
size and type tires on all wheels.
It's all right to drive with your compact spare,
though. It was developed for use on your vehicle.
CAUTION:
If you use bias-ply tires on your vehicle, the
wheel rim flanges could develop cracks after
many miles of driving. A tire and/or wheel could
fail suddenly, causing a crash. Use only radial
-ply
tires with the wheels on your vehicle.
Uniform Tire Quality Grading
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
treadwear, traction and temperature performance.
(This applies only to vehicles sold in the United States.)
The grades are molded on the sidewalls of most
passenger car tires. The Uniform Tire Quality Grading
system does not apply to deep tread, winter
-type snow
tires, space
-saver or temporary use spare tires, tires with
nominal rim diameters of 10 to 12 inches (25 to 30 cm),
or to some limited
-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades, they must also conform to Federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.

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Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specified government test course. For
example, a tire graded 150 would wear one and a half
(1 1/2) 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 Vehicle 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.