2003 BUICK CENTURY check engine light

Clean and dry the key. Wait about three minutes and try
again. If the starter still won't work, and the key
appears to be clean and dry, wait about three minutes
and try another ignition key. At this time, you may
also want to check the fuse. See
Fuses and Circuit
Breakers on page 5-89. If the starter won't work with the
other key, your vehicle needs service. If your vehicle
does start, the ®rst ignition key may be faulty. See your
dealer or a locksmith who can service the PASS-Key
žII.
If you accidentally use a key that has a damaged or
missing resistor pellet, the starter won't work. The
SECURITY warning light on the instrument panel will
then come on. But you don't have to wait three minutes
before trying another ignition key.
See your dealer or a locksmith who can service the
PASS-Key
žII to have a new key made.If you're ever driving and the SECURITY warning light
comes on, you will be able to restart your engine if
you turn it off. Your PASS-Key
žII system, however, is
not working properly and must be serviced by your
dealer. Your vehicle is not protected by the
PASS-Key
žII system.
If you lose or damage a PASS-Key
žII ignition key, see
your dealer or a locksmith who can service
PASS-Key
žII to have a new key made. Also, seeRoadside Assistance Program on page 7-6for more
information.
2-18

Warning Lights, Gages and
Indicators
This part describes the warning lights and gages that may
be on your 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
your 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 your vehicle's functions. As you will
see in the details on the next few pages, some
warning lights come on brie¯y when you start the
engine just to let you know they're 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's 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 your warning lights
and gages. They're a big help.
3-22

Engine Coolant Temperature Gage
You have a gage that
shows the engine coolant
temperature. If the
gage pointer moves into
the red area, your
engine is too hot!
This reading means the same thing as the warning light.
It means that your engine coolant has overheated. If
you have been operating your vehicle under normal
driving conditions, you should pull off the road, stop your
vehicle and turn off the engine as soon as possible.
See
Engine Overheating on page 5-26.
Tire Pressure Light
Your vehicle may have a
tire pressure monitor that
can alert you to a large
change in the pressure in
one tire.
After the system has ªlearnedº tire pressures with
properly in¯ated 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 tire in¯ation monitor
system won't alert you 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, you should stop as
soon as you can and check all your tires for damage.
If a tire is ¯at, see
If a Tire Goes Flat on page 5-66. Also
check the tire pressure in all four tires as soon as you
can. See
In¯ation Ð Tire Pressure on page 5-57.
The light will stay on, while the ignition is on, until you
reset (calibrate) the system. See
Tire Pressure
Monitor System on page 5-58.
3-30

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:Modi®cations 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.
Modi®cations 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 doesn't come on, have it
repaired. This light will also come on during a
malfunction in one of two ways:
·Light FlashingÐ A mis®re condition has been
detected. A mis®re increases vehicle emissions and
may damage the emission control system on your
vehicle. Diagnosis and service may be required.
·Light On SteadyÐ An emission control system
malfunction has been detected on your vehicle.
Diagnosis and service may be required.
3-31

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.
Emissions Inspection and Maintenance
Programs
Some state/provincial and local governments have or
may begin programs to inspect the emission control
equipment on your vehicle. Failure to pass this
inspection could prevent you from getting a vehicle
registration.Here are some things you need to know to help your
vehicle pass an inspection:
Your vehicle will not pass this inspection if the SERVICE
ENGINE SOON light is on or not working properly.
Your vehicle will not pass this inspection if the OBD
(on-board diagnostic) system determines that critical
emission control systems have not been completely
diagnosed by the system. The vehicle would be
considered not ready for inspection. This can happen if
you have recently replaced your battery or if your
battery has run down. The diagnostic system is
designed to evaluate critical emission control systems
during normal driving. This may take several days
of routine driving. If you have done this and your vehicle
still does not pass the inspection for lack of OBD
system readiness, your GM dealer can prepare the
vehicle for inspection.
3-33

Oil Pressure Light
If you have a problem with
your oil, this light may stay
on after you start your
engine, or come on when
you are driving.
This indicates that oil is not going through your engine
quickly enough to keep it lubricated. The engine
could be low on oil or could have some other oil
problem. Have it ®xed right away.
The oil light could also come on in the following
situations:
·The light will come on brie¯y when you turn on the
ignition to show you that it is working properly. If it
doesn't come on with the ignition on, you may
have a problem with the fuse or bulb. Have it ®xed
right away.
·Sometimes when the engine is idling at a stop, the
light may blink on and off. This is normal.
{CAUTION:
Don't keep driving if the oil pressure is low. If
you do, your engine can become so hot that it
catches ®re. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice:Damage to your engine from neglected oil
problems can be costly and is not covered by
your warranty.
3-34

Low Oil Level Light
If your vehicle is equipped
with an oil level monitoring
system, the LOW OIL
light will come on brie¯y
when the ignition key
is turned on.
If the light does not come on brie¯y, have it ®xed so it
will be ready to warn you if there's a problem.
If the light stays on, stop the vehicle on a level surface
and turn the engine off. Check the oil level using the
engine oil dipstick. See
Engine Oil on page 5-13.Ifthe
light does not come on brie¯y, have the low oil level
sensor system repaired so it will be ready to warn you if
there's a problem.
The oil level monitoring system only checks oil level
during the brief period between key on and engine
crank. It does not monitor engine oil level when
the engine is running. Additionally, an oil level check is
only performed if the engine has been turned off for
a considerable period of time, allowing the oil normally
in circulation to drain back into the oil pan.
Change Engine Oil Light
The CHANGE OIL SOON
light should come on
brie¯y as a bulb check
when you start the engine.
If the light doesn't come
on, have it serviced.
If the CHANGE OIL SOON light comes on and stays on
after you start the engine, have the oil changed.
For additional information, see ªWhen to Change Engine
Oil (GM Oil Life System)º under
Engine Oil on page 5-13.
To reset the CHANGE OIL SOON light, see ªHow to
Reset the Systemº under
Engine Oil on page 5-13.
3-35

Avoid needless heavy braking. Some people drive in
spurts Ð heavy acceleration followed by heavy
braking Ð rather than keeping pace with traffic. This is
a mistake. Your brakes may not have time to cool
between hard stops. Your brakes will wear out much
faster if you do a lot of heavy braking. If you keep pace
with the traffic and allow realistic following distances,
you will eliminate a lot of unnecessary braking.
That means better braking and longer brake life.
If your engine ever stops while you're driving, brake
normally but don't pump your brakes. If you do,
the pedal may get harder to push down. If your engine
stops, you will still have some power brake assist.
But you will use it when you brake. Once the power
assist is used up, it may take longer to stop and
the brake pedal will be harder to push.Anti-lock Brake System (ABS)
Your vehicle may have anti-lock brakes. ABS is an
advanced electronic braking system that will help
prevent a braking skid.
If your vehicle has anti-lock brakes, this warning light on
the instrument panel will come on brie¯y when you
start your vehicle.
When you start your engine, or when you begin to drive
away, your anti-lock brake system will check itself.
You may hear a momentary motor or clicking noise while
this test is going on, and you may even notice that
your brake pedal moves or pulses a little. This is normal.United States
Canada
4-7