1999 BUICK CENTURY service indicator

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2-58 Malfunction Indicator Lamp
(Service Engine Soon Light)
Your vehicle is equipped
with a computer which
monitors operation of the
fuel, ignition and emission
control systems.
This system is called OBD II (On
-Board
Diagnostics
-Second Generation) and is intended to assure
that emissions are at acceptable levels for the life of the
vehicle, helping to produce a cleaner environment. The
SERVICE ENGINE SOON light comes on and a chime
will sound to indicate that there is a problem and service is
required. Malfunctions often will be indicated by the
system before any problem is apparent. This may prevent
more serious damage to your vehicle. This system is also
designed to assist your service technician in correctly
diagnosing any malfunction.
NOTICE:
If you keep driving your vehicle with this light
on, after a while, your emission controls may not
work as well, your fuel economy may not be as
good and your engine may not run as smoothly.
This could lead to costly repairs that may not be
covered by your warranty.
NOTICE:
Modifications made to the engine, transaxle,
exhaust or fuel system of your vehicle or the
replacement of the original tires with other than
those of the same Tire Performance Criteria
(TPC) can affect your vehicle's emission controls
and may cause the SERVICE ENGINE SOON
light to come on. Modifications to these systems
could lead to costly repairs not covered by your
warranty. This may also result in a failure to pass
a required Emission Inspection/Maintenance test.

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2-63 Service Vehicle Soon Light
THE SERVICE VEHICLE
SOON light will come on if
you have certain
non
-emission related
vehicle problems.
These problems may not be obvious and may affect
vehicle performance or durability. Consult a qualified
dealership for necessary repairs to maintain top vehicle
performance. The light will come on briefly when your
ignition is turned on to show that it is working properly.
Low Washer Fluid Warning Light
The LOW WASH light will
come on when your
windshield washers are
working and the fluid
container is low.
The light will also come on briefly when your ignition is
turned on to show that it is working properly.
Door/Trunk Ajar Warning Light
The DOOR/TRUNK light
will come on if your trunk
or any door is not
completely closed.
Fuel Gage
Your fuel gage tells you
about how much fuel you
have left when the ignition
is on. When the indicator
nears EMPTY (E), you still
have a little fuel left, but
you should get more soon.

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3-31 Care of Your Cassette Tape Player
A tape player that is not cleaned regularly can cause
reduced sound quality, ruined cassettes or a damaged
mechanism. Cassette tapes should be stored in their
cases away from contaminants, direct sunlight and
extreme heat. If they aren't, they may not operate
properly or may cause failure of the tape player.
Your tape player should be cleaned regularly after every
50 hours of use. Your radio may display CLN to indicate
that you have used your tape player for 50 hours without
resetting the tape clean timer. If this message appears on
the display, your cassette tape player needs to be
cleaned. It will still play tapes, but you should clean it as
soon as possible to prevent damage to your tapes and
player. If you notice a reduction in sound quality, try a
known good cassette to see if it is the tape or the tape
player at fault. If this other cassette has no improvement
in sound quality, clean the tape player.
The recommended cleaning method for your cassette
tape player is the use of a scrubbing action,
non
-abrasive cleaning cassette with pads which scrub
the tape head as the hubs of the cleaner cassette turn.
The recommended cleaning cassette is available through
your dealership (GM Part No. 12344789).When using a scrubbing action, non
-abrasive cleaning
cassette, it is normal for the cassette to eject because
your unit is equipped with a cut tape detection feature
and a cleaning cassette may appear as a broken tape.
If the cleaning cassette ejects, insert the cassette at least
three times to ensure thorough cleaning.
You may also choose a non
-scrubbing action, wet-type
cleaner which uses a cassette with a fabric belt to clean
the tape head. This type of cleaning cassette will not
eject on its own. A non
-scrubbing action cleaner may
not clean as thoroughly as the scrubbing type cleaner.
The use of a non
-scrubbing action, dry-type cleaning
cassette is not recommended.
After you clean the player, press and hold EJECT for
five seconds to reset the CLN indicator. The radio will
display
--- to show the indicator was reset.
Cassettes are subject to wear and the sound quality
may degrade over time. Always make sure the cassette
tape is in good condition before you have your tape
player serviced.

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6-4
If your vehicle is certified to meet California Emission
Standards (indicated on the underhood emission control
label), it is designed to operate on fuels that meet
California specifications. If such fuels are not available
in states adopting California emissions standards, your
vehicle will operate satisfactorily on fuels meeting
federal specifications, but emission control system
performance may be affected. The malfunction indicator
lamp on your instrument panel may turn on and/or your
vehicle may fail a smog
-check test. (See ªMalfunction
Indicator Lampº in the Index.) If this occurs, return to
your authorized Buick dealer for diagnosis to determine
the cause of failure. In the event it is determined that the
cause of the condition is the type of fuels used, repairs
may not be covered by your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane
-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask your service station operator whether or not
the fuel contains MMT. General Motors does not
recommend the use of such gasolines. If fuels containing
MMT are used, spark plug life may be reduced and your
emission control system performance may be affected.
The malfunction indicator lamp on your instrument
panel may turn on. If this occurs, return to your
authorized Buick dealer for service.To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent deposits from forming in your engine and fuel
system, allowing your emission control system to
function properly. Therefore, you should not have to add
anything to the fuel. In addition, gasolines containing
oxygenates, such as ethers and ethanol, and
reformulated gasolines may be available in your area to
contribute to clean air. General Motors recommends that
you use these gasolines, particularly if they comply with
the specifications described earlier.
NOTICE:
Your vehicle was not designed for fuel that
contains methanol. Don't use it. It can corrode
metal parts in your fuel system and also damage
plastic and rubber parts. That damage wouldn't
be covered under your warranty.

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6-15 Engine Oil Additives
Don't add anything to your oil. Your dealer is ready to
advise if you think something should be added.
When to Change Engine Oil
Your vehicle has a computer that lets you know when to
change your engine oil. This is not based on mileage,
but on engine revolutions and engine operating
temperature. When the computer has calculated that the
oil needs changing, the Oil Life Monitor will indicate
that a change is necessary. The mileage between oil
changes will vary depending on how you drive your
vehicle
-- usually between 3,000 miles (5 000 km) and
7,500 miles (12 500 km) since your last oil change.
Under severe conditions, the indicator may come on
before 3,000 miles (5 000 km). Never drive your vehicle
more than 7,500 miles (12 500 km) or 12 months
(whichever occurs first) without an oil change.
The system won't detect dust in the oil. So, if you
drive in a dusty area, be sure to change your oil every
3,000 miles (5 000 km) or sooner. Remember to
reset the CHANGE OIL SOON light whenever the oil
is changed.How to Reset the Oil Life Monitor
After changing the engine oil, the system must be reset.
With the ignition key in RUN but the engine off, fully
push and release the accelerator pedal slowly three times
within five seconds. If the CHANGE OIL SOON light
flashes, the system is resetting. Turn the key to OFF,
then start the vehicle. If the CHANGE OIL SOON
light comes back on, the system has not reset. Repeat
the procedure.
What to Do with Used Oil
Did you know that used engine oil contains certain
elements that may be unhealthy for your skin and could
even cause cancer? Don't let used oil stay on your skin
for very long. Clean your skin and nails with soap and
water, or a good hand cleaner. Wash or properly throw
away clothing or rags containing used engine oil. (See
the manufacturer's warnings about the use and disposal
of oil products.)
Used oil can be a real threat to the environment. If you
change your own oil, be sure to drain all free
-flowing oil
from the filter before disposal. Don't ever dispose of oil
by putting it in the trash, pouring it on the ground, into
sewers, or into streams or bodies of water. Instead,
recycle it by taking it to a place that collects used oil. If
you have a problem properly disposing of your used oil,
ask your dealer, a service station or a local recycling
center for help.

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6-29 Brake Wear
Your vehicle has front disc brakes and rear drum 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 may
come and go or be heard all the time your vehicle is
moving (except when you are pushing on the brake
pedal firmly).
CAUTION:
The brake wear warning sound means that soon
your brakes won't work well. That could lead to
an accident. When you hear the brake wear
warning sound, have your vehicle serviced.
NOTICE:
Continuing to drive with worn-out brake pads
could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly torque wheel nuts in the
proper sequence to GM specifications.
Brake linings should always be replaced as complete
axle sets.
See ªBrake System Inspectionº in Section 7 of this
manual under Part C ªPeriodic Maintenance
Inspections.º
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 of brake trouble.
Brake Adjustment
Every time you apply the brakes, with or without the
vehicle moving, your brakes adjust for wear.

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6-32
5. Remove the rubber access cover (from behind the
bulb you are replacing).
6. Quarter twist and turn the bulb socket and remove it
from the lamp.
7. Lift the plastic locking tab on the electrical
connector and pull the connector from the headlamp
bulb socket.8. Connect the new headlamp bulb to the wiring harness,
making sure the connector tab snaps into place.
9. Insert the bulb socket into the headlamp assembly.
10. Reverse all steps and reassemble the headlamp
assembly, then check the lamps.
Headlamp Aiming
Your vehicle has a headlamp system equipped with
horizontal and vertical aim indicators. The aim has been
pre
-set at the factory and should need no further
adjustment. This is true even though your vertical and
horizontal aim indicators may not fall exactly on the ª0º
(zero) marks on their scales.
If your vehicle is damaged in an accident, the headlamp
aim may be affected. Aim adjustment may be necessary
if it is difficult to see lane markers (for horizontal aim),
or if oncoming drivers flash their high beams at you (for
vertical aim). If you believe your headlamps need to be
re
-aimed, we recommend that you take it to your dealer
for service; however, it is possible for you to re
-aim
your headlamps as described in the following procedure.

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Scheduled Maintenance
7-5
The services shown in this schedule up to 100,000 miles
(166 000 km) should be performed after 100,000 miles
(166 000 km) at the same intervals. The services shown
at 150,000 miles (240 000 km) should be performed at
the same interval after 150,000 miles (240 000 km).
See ªOwner Checks and Servicesº and ªPeriodic
Maintenance Inspectionsº following.
Footnotes

The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to the
completion of the vehicle's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the maintenance
be recorded.* Your vehicle has an Engine Oil Life Monitor. This
monitor will show you when to change the engine oil
and filter
-- usually between 3,000 miles (5 000 km) and
7,500 miles (12 500 km) since your last oil change.
Under severe conditions, the indicator may come on
before 3,000 miles (5 000 km). Never drive your vehicle
more than 7,500 miles (12 500 km) or 12 months
without an oil and filter change.
The system won't detect dust in the oil. So if you drive
in a dusty area, be sure to change your oil and filter
every 3,000 miles (5 000 km) or sooner if the CHANGE
OIL SOON light comes on. Remember to reset the Oil
Life Monitor whenever the oil is changed. For more
information, see ªChange Oil Soon Lightº in the Index.
+ A good time to check your brakes is during tire
rotation. See ªBrake System Inspectionº under ªPeriodic
Maintenance Inspectionsº in Part C of this schedule.