check engine BUICK CENTURY 2004 Owner's Manual

The ignition key must be clean and dry before it is
inserted in the ignition or the engine may not start. If the
engine does not start and the SECURITY warning
light on the instrument panel is ashing, the key may be
dirty or wet. Turn the ignition off.
Clean and dry the key. Wait about three minutes and try
again. If the vehicle still does not start, the ignition
key may be faulty. Wait about three more minutes and
try a spare ignition key. At this time, you may also
want to check the fuse. SeeFuses and Circuit Breakers
on page 5-97for information on fuse location. If the
starter will not work with the spare key, the vehicle
needs service. See your dealer or a locksmith who can
service the PASS-Key
®II.
If a key is accidentally used that has a damaged or
missing resistor pellet, the starter will not work.
The SECURITY warning light on the instrument panel
will then come on. But you do not have to wait three
minutes before trying another ignition key.
See your dealer or a locksmith who can service the
PASS-Key
®II to have a new key made.
If the SECURITY warning light comes on the instrument
panel while the vehicle is being driven, the engine
will still be able to be started after it is turned off. The
PASS-Key
®II system, however, is not working properly
and must be serviced by your dealer. The vehicle is
not protected by the PASS-Key
®II system when
this happens.If a PASS-Key
®II ignition key is lost or damaged,
see your dealer or a locksmith who can service
PASS-Key
®II to have a new key made. Also, see
Roadside Assistance Program on page 7-5for more
information.
Starting and Operating Your
Vehicle
New Vehicle Break-In
Notice:Your vehicle does not need an elaborate
“break-in.” But it will perform better in the long run
if you follow these guidelines:
Do not drive at any one speed — fast or
slow — for the rst 500 miles (805 km). Do not
make full-throttle starts.
Avoid making hard stops for the rst 200 miles
(322 km) or so. During this time your new
brake linings are not yet broken in. Hard stops
with new linings can mean premature wear
and earlier replacement. Follow this breaking-in
guideline every time you get new brake
linings.
Do not tow a trailer during break-in. SeeTowing
a Trailer on page 4-39for more information.
2-18

Retained Accessory Power (RAP)
If the vehicle has Retained Accessory Power (RAP), the
power windows and audio system can continue to
operate for up to 10 minutes after the ignition key is
turned to OFF and before any of the doors are opened.
Starting Your Engine
Move the shift lever to PARK (P) or NEUTRAL (N). The
engine will not start in any other position – that is a
safety feature. To restart the vehicle when it is already
moving, use NEUTRAL (N) only.
Notice:Shifting into PARK (P) with the vehicle
moving could damage the transaxle. Shift into
PARK (P) only when your vehicle is stopped.
1. With your foot off the accelerator pedal, turn the
ignition key to START. When the engine starts,
let go of the key. The idle speed will go down as the
engine gets warm.Notice:Holding your key in START for longer than
15 seconds at a time will cause your battery to
be drained much sooner. And the excessive heat
can damage your starter motor. Wait about
15 seconds between each try to help avoid draining
your battery or damaging your starter.
2. If the engine will not start, or starts but then stops,
it could be ooded with too much gasoline. Try
pushing the accelerator pedal all the way to the oor
and holding it there as the key is held in START
for not more than 15 seconds at a time. This clears
the extra gasoline from the engine
Notice:Your engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way the
engine operates. Before adding electrical equipment,
check with your dealer. If you do not, your engine
might not perform properly.
2-20

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.
3-27

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.
3-36

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.
3-37

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.
3-38

Oil Pressure Light
If the vehicle has a an oil
problem, this light may
stay on after the engine is
started, or come on
while you are driving.
This light indicates that oil is not going through the
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 briey when the ignition is
turned on to show that it is working properly. If it
does not come on with the ignition on, there may be
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:
Do not 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:Lack of proper engine oil maintenance may
damage the engine. The repairs would not be
covered by your warranty. Always follow the
maintenance schedule in this manual for changing
engine oil.
3-40

Change Engine Oil Light
The CHANGE OIL SOON
light should come on
briey as a bulb check
when the engine is started.
If the light does not
come on, have it serviced.
If the CHANGE OIL SOON light comes on and stays on
after the engine is started, have the oil changed.
For additional information, see “When to Change Engine
Oil (GM Oil Life System)” underEngine Oil on
page 5-13. To reset the CHANGE OIL SOON light, see
“How to Reset the System” underEngine Oil on
page 5-13.
Security Light
The SECURITY light will
come on when the key is
turned to START, and
will stay on until the
vehicle starts.
It will also ash if the ignition key is too dirty or wet for
the PASS-Key
®II system to read the resistor pellet.
SeePASS-Key®II on page 2-17.
If the resistor pellet is damaged or missing, the light will
come on.
3-41

Low Fuel Warning Light
If the vehicle’s fuel is low, a circular light on the
instrument panel cluster will come on and a chime will
sound periodically until fuel is added to the fuel tank.
It will also come on for a few seconds when the ignition
is turned on as a check to indicate it is working. If it
does not come on then, have it xed.
Audio System(s)
Notice:Before you add any sound equipment to
your vehicle – like a tape player, CB radio, mobile
telephone or two-way radio – be sure you can
add what you want. If you can, it’s very important to
do it properly. Added sound equipment may
interfere with the operation of your vehicle’s engine,
radio or other systems, and even damage them.
Your vehicle’s systems may interfere with the
operation of sound equipment that has been added
improperly.
So, before adding sound equipment, check with
your dealer and be sure to check federal rules
covering mobile radio and telephone units.
Your audio system has been designed to operate easily
and to give years of listening pleasure. You will get
the most enjoyment out of it if you acquaint yourself with
it rst. Figure out which radio you have in your vehicle,
nd out what your audio system can do and how to
operate all of its controls to be sure you’re getting the
most out of the advanced engineering that went into it.
Your vehicle has a feature called Retained Accessory
Power (RAP). With RAP, you can play your audio
system even after the ignition is turned off. See
“Retained Accessory Power (RAP)” underIgnition
Positions on page 2-19. United States
Canada
3-44

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.
Let us say the road is wet and you are driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here is what
happens with ABS:A computer senses that wheels are slowing down. If
one of the wheels is about to stop rolling, the computer
will separately work the brakes at each wheel.
The anti-lock system can change the brake pressure
faster than any driver could. The computer is
programmed to make the most of available tire and road
conditions. This can help you steer around the obstacle
while braking hard.
As you brake, your computer keeps receiving updates
on wheel speed and controls braking pressure
accordingly.
4-7