light BUICK CENTURY 2004 Owner's Guide

8. Replace the old air
lter by pulling up on
its tab.
9. Install a new passenger compartment air lter. See
Normal Maintenance Replacement Parts on
page 6-13for the type of lter to use. Make sure it
slides under the compartment retainers.
10. Reverse Steps 1 through 6.
Warning Lights, Gages and
Indicators
This part describes the warning lights and gages that
may be on the vehicle. The pictures will help you
locate them.Warning lights and gages can signal that something is
wrong before it becomes serious enough to cause
an expensive repair or replacement. Paying attention to
the warning lights and gages could also save you or
others from injury.
Warning lights come on when there may be or is a
problem with one of the vehicle’s functions. As you will
see in the details on the next few pages, some
warning lights come on briey when you start the
engine just to let you know they are working. If you are
familiar with this section, you should not be alarmed
when this happens.
Gages can indicate when there may be or is a problem
with one of your vehicle’s functions. Often gages
and warning lights work together to let you know when
there is a problem with your vehicle.
When one of the warning lights comes on and stays
on when you are driving, or when one of the gages
shows there may be a problem, check the section
that tells you what to do about it. Please follow this
manual’s advice. Waiting to do repairs can be
costly – and even dangerous. So please get to know
the warning lights and gages. They are a big help.
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Safety Belt Reminder Light
When the ignition key is turned to RUN or START, a
chime will come on for several seconds to remind
occupants to fasten their safety belts.
The safety belt light will
also come on and stay
on for several seconds,
then it will ash for
several more.
If the driver’s belt is already buckled, neither the chime
nor the light will come on.
Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows the air bag symbol. The system
checks the air bag’s electrical system for malfunctions.
The system check includes the air bag modules, the
wiring and the crash sensing and diagnostic module. For
more information on the air bag system, seeAir Bag
Systems on page 1-49.
This light will come on
when the vehicle is
started, and it will ash for
a few seconds. Then
the light should go out.
This means the system is
functioning properly.
If the air bag readiness light stays on after the vehicle is
started, or comes on as the vehicle is being driven,
there may be an electrical problem and the air
bag system may not work properly. Have the vehicle
serviced right away.
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{CAUTION:
If the air bag readiness light stays on after you
start your vehicle, it means the air bag system
may not be working properly. The air bags in
your vehicle may not inate in a crash, or they
could even inate without a crash. To help
avoid injury to yourself or others, have your
vehicle serviced right away if the air bag
readiness light stays on after you start your
vehicle.
The air bag readiness light should ash for a few
seconds when you turn the ignition key to RUN. If the
light does not come on then, have it xed so it will
be ready to warn you if there is a problem.
Charging System Light
The charging system light
will come on briey when
the ignition is turned
on, as a check to show
that it is working. Then it
should go out.
If it stays on, or comes on while the vehicle is being
driven, there may be a problem with the charging
system. It could indicate that the vehicle has a loose
accessory belt or another electrical problem. Have
it checked right away. Driving while this light is on could
drain the battery.
If the vehicle must be driven a short distance with the
light on, be certain to turn off all the accessories,
such as the radio and air conditioner.
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Brake System Warning Light
The vehicle’s hydraulic brake system is divided into two
parts. If one part is not working, the other part can
still work and stop the vehicle. For good braking, though,
you need both parts working well.
If the warning light comes on, there is a brake problem.
Have the brake system inspected right away.
This light should come on briey when the ignition key
is turned to RUN. If it does not come on then, have
it xed so it will be ready to warn you if there is a
problem.When the ignition is on, the brake system warning light
will also come on when the parking brake is set.
The light will stay on if the parking brake does not
release fully. If it stays on after the parking brake is fully
released, it means there is a brake problem.
If the light comes on while the vehicle is being driven,
pull off the road and stop carefully. The pedal may
be harder to push. or it may go closer to the oor. It may
take longer to stop. If the light is still on, have the
vehicle towed for service. SeeTowing Your Vehicle on
page 4-31.
{CAUTION:
Your brake system may not be working
properly if the brake system warning light is
on. Driving with the brake system warning light
on can lead to an accident. If the light is still
on after you have pulled off the road and
stopped carefully, have the vehicle towed for
service. United StatesCanada
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Anti-Lock Brake System Warning
LightIf the vehicle has anti-lock brakes, this warning light will
come on for a few seconds when the ignition key is
turned to RUN. If the anti-lock brake system warning
light stays on longer than normal after the engine
has been started, turn the ignition off. Or, if the light
comes on and stays on while the vehicle is being driven,
stop as soon as possible and turn the ignition off.
Then start the engine again to reset the system. If the
light still stays on, or comes on again while driving,
the anti-lock brake system needs service. If the light is
on and the regular brake system warning light is not
on, the vehicle still has brakes, but it does not have
anti-lock brakes.
The anti-lock brake system warning light will come on
briey when the ignition key is turned to RUN. This
is normal. If the light does not come on then, have it
xed so it will be ready to warn you if there is a problem. United States
Canada
3-33

Enhanced Traction System Warning
Light
If the vehicle has the
Enhanced Traction
System, (ETS) the warning
light may come on for
the following reasons:
When the vehicle is shifted to SECOND (2) or
FIRST (1). To turn the system back on, shift
to THIRD (3) or AUTOMATIC OVERDRIVE (
X).
SeeEnhanced Traction System (ETS) on page 4-9.
If the vehicle needs service. Adjust your driving
accordingly.
When the parking brake is set with the engine
running, and the parking brake does not
release fully.
After the parking brake is fully released and the
transaxle shift lever is in any position other
than FIRST (1) or SECOND (2). This means there
is a problem with the system.
If an engine-related problem affects the ETS and
turns the system off.
When the ETS warning light is on, the system will not
limit wheel spin. Adjust your driving accordingly.
Low Traction Light
If the vehicle has the
Enhanced Traction System
(ETS), this light will
come on when the system
is limiting wheel spin.
You may feel or hear the system working, but this is
normal. Slippery road conditions may exist if the
low traction light comes on, so adjust your driving
accordingly. The light will stay on for a few seconds after
the ETS stops limiting wheel spin. SeeEnhanced
Traction System (ETS) on page 4-9.
The low traction light also comes on briey when the
ignition key is turned to RUN. If the light does not come
on then, have it xed so it will function properly to
indicate when the Enhanced Traction System is active.
3-34

Engine Coolant Temperature
Warning Light
This light indicates that the
engine coolant has
overheated or the radiator
cooling fan is not
working.
The light will come on briey when the ignition is turned
on to show that it is working.
If the vehicle has been operating under normal driving
conditions, pull off the road, stop the vehicle and turn off
the engine as soon as possible. SeeEngine
Overheating on page 5-25.
Engine Coolant Temperature Gage
The vehicle has a gage
that shows the engine
coolant temperature. If the
gage pointer moves into
the red area, the engine is
too hot.
This reading indicates the same thing as the warning
light. It means that the engine coolant has overheated. If
the vehicle has been operating under normal driving
conditions, pull off the road, stop the vehicle and turn off
the engine as soon as possible. SeeEngine
Overheating on page 5-25.
3-35

Tire Pressure Light
The vehicle may have a
tire pressure monitor that
indicates a large change
in the pressure in one tire.
The system stores the tire pressures of the vehicle’s
properly inated tires. The LOW TIRE light will come on
if the pressure in one tire becomes 12 psi (83 kPa)
lower than the other three tires. The LOW TIRE light will
not come on if the pressure in more than one tire is
low, if the system is not yet calibrated, or if the vehicle
is moving faster than 70 mph (110 km/h).
When the LOW TIRE light comes on, stop as soon as
possible and check all the tires for damage. If a tire
is at, seeIf a Tire Goes Flat on page 5-74. Also check
the tire pressure in all four tires as soon as possible.
SeeInation - Tire Pressure on page 5-64.
The light will stay on, while the ignition is on, until the
system is reset. SeeTire Pressure Monitor System
on page 5-65.
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.
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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:Modications made to the engine,
transaxle, exhaust, intake 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 this light to come on.
Modications 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.
This light should come on, as a check to show you it is
working, when the ignition is on and the engine is
not running. If the light does not come on, have it
repaired. This light will also come on during a
malfunction in one of two ways:
Light Flashing— A misre condition has been
detected. A misre increases vehicle emissions
and may damage the emission control system on
your vehicle. Diagnosis and service may be
required.
Light On Steady— An emission control system
malfunction has been detected on your vehicle.
Diagnosis and service may be required.
If the Light Is Flashing
The following may prevent more serious damage to
your vehicle:
Reducing vehicle speed.
Avoiding hard accelerations.
Avoiding steep uphill grades.
If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.
If the light stops ashing and remains on steady, see “If
the Light Is On Steady” following.
If the light continues to ash, when it is safe to do so,
stop the vehicle.Find a safe place to park your vehicle.
Turn the key off, wait at least 10 seconds and restart
the engine. If the light remains on steady, see “If
the Light Is On Steady” following. If the light is still
ashing, follow the previous steps, and see your dealer
for service as soon as possible.
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If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully install
the cap. SeeFilling Your Tank on page 5-7. The
diagnostic system can determine if the fuel cap has
been left off or improperly installed. A loose or missing
fuel cap will allow fuel to evaporate into the atmosphere.
A few driving trips with the cap properly installed
should turn the light off.
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition
will usually be corrected when the electrical system
dries out. A few driving trips should turn the light off.Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane on page 5-4. Poor fuel quality will
cause your engine not to run as efficiently as designed.
You may notice this as stalling after start-up, stalling
when you put the vehicle into gear, misring, hesitation
on acceleration or stumbling on acceleration. (These
conditions may go away once the engine is warmed up.)
This will be detected by the system and cause the
light to turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at least
one full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn off,
your dealer can check the vehicle. Your dealer has
the proper test equipment and diagnostic tools to x any
mechanical or electrical problems that may have
developed.
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