2001 BUICK CENTURY check engine light

2-21
PASS-Key
II
Your vehicle is equipped
with the PASS
-Key II
(Personalized Automotive
Security System)
theft
-deterrent system.
PASS
-Key II is a passive
theft
-deterrent system.
It works when you insert
or remove the key from
the ignition.
PASS
-Key II uses a resistor pellet in the ignition key
that matches a decoder in your vehicle.
When the PASS
-Key II system senses that someone is
using the wrong key, it shuts down the vehicle's starter and
fuel systems. For about three minutes, the starter won't
work and fuel won't go to the engine. If someone tries to
start your vehicle again or uses another key during this
time, the vehicle will not start. This discourages someone
from randomly trying different keys with different resistor
pellets in an attempt to make a match.
The ignition key must be clean and dry before it's inserted
in the ignition or the engine may not start. If the engine
does not start and the SECURITY light is flashing,
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 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 ªFuses and Circuit Breakersº in
the Index). If the starter won't work with the other key,
your vehicle needs service. If your vehicle does start,
the first ignition key may be faulty. See your dealer
or a locksmith who can service the PASS
-Key II.
If you accidentally use a key that has a damaged or
missing resistor pellet, the starter won't work. The
SECURITY light 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 II to have a new key made.
If you're ever driving and the SECURITY light comes
on, you will be able to restart your engine if you turn it
off. Your PASS
-Key II system, however, is not working
properly and must be serviced by your dealer. Your
vehicle is not protected by the PASS
-Key II system.
If you lose or damage a PASS
-Key II ignition key,
see your dealer or a locksmith who can service
PASS
-Key II to have a new key made. Also,
see ªRoadside Assistanceº in the Index for
more information.

2-55

Roadside Assistance with Location -- For vehicle
breakdowns, press the OnStar button. An advisor
will contact the appropriate help.

Remote Diagnostics
-- If an instrument panel
light comes on, the center can perform a check of
the engine on
-board computer. An advisor can then
recommend what action needs to be taken.

OnStar MED
-NET -- Med-Net can store your
personal medical history and provide it to emergency
personnel if necessary.

Accident Assist
-- An advisor can provide
step
-by-step guidance following an accident.

Remote Door Unlock
-- To contact the center, call
1
-888-4-ONSTAR. You will be required to provide
your security information. An advisor will send a
command to your vehicle to unlock itself. The
advisor can delay unlocking your vehicle. Remote
Door Unlock is disabled 48 hours after the vehicle is
parked to maintain the battery charge.
Vehicle Locator Service
-- To contact the center,
call 1
-888-4-ONSTAR. You will be required to
provide your security information. An advisor will
send a command to your vehicle to sound the horn
and/or flash the lamps.
In order to provide you with excellent service, calls with
the OnStar Center may be monitored or recorded.
Premium Services (Includes Safety and
Security Services)

Route Support -- An advisor can provide directions
or guidance to anywhere you want to go. In addition,
they can help you locate gas stations, rest areas,
ATMs, hospitals, hotels, stores, eateries and more.

Concierge Services
-- The concierge advisor can
obtain tickets, reservations, or help with vacation/trip
planning and other unique items and services.

Ride Assist
-- An advisor can locate transportation
in the event that you are unable to drive.

2-62
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 briefly 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.
Safety Belt Reminder Light
When the key is turned to RUN or START, a chime will
come on for about eight seconds to remind people to
fasten their safety belts, unless the driver's safety belt is
already buckled.
The safety belt light will
also come on and stay on
for about 20 seconds,
then it will flash for
about 55 seconds.
If the driver's belt is already buckled, neither the chime
nor the light will come on.

2-69 Low Tire Light
The low tire inflation
monitor system can
alert you to a large
change in the pressure
in one tire.
After the system has ªlearnedº tire pressures with
properly inflated 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 inflation
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 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 stay on (while the ignition is on) until you
reset (calibrate) the system. See ªLow Tire Inflation
Monitor Systemº in the Index.
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.

2-70
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, 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 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.
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 Flashing
-- A misfire condition has been
detected. A misfire increases vehicle emissions and
may damage the emission control system on your
vehicle. Dealer or qualified service center diagnosis
and service may be required.

Light On Steady
-- An emission control system
malfunction has been detected on your vehicle.
Dealer or qualified service center 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.

2-71
If the light stops flashing and remains on steady,
see ªIf the Light Is On Steadyº following.
If the light continues to flash, 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 ªIf the Light
Is On Steadyº following. If the light is still flashing,
follow the previous steps, and drive the vehicle to your
dealer or qualified service center for service.
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. See ªFilling Your Tankº in the Index. 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.Are you low on fuel?
As your engine starts to run out of fuel, your engine
may not run as efficiently as designed since small
amounts of air are sucked into the fuel line causing a
misfire. The system can detect this. Adding fuel
should correct this condition. Make sure to install the
fuel cap properly. See ªFilling Your Tankº in the Index.
It will take a few driving trips to turn the light off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel.
See ªFuelº in the Index. 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, misfiring,
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,
have your dealer or qualified service center check the
vehicle. Your dealer has the proper test equipment and
diagnostic tools to fix any mechanical or electrical
problems that may have developed.

2-73
CAUTION:
Don't keep driving if the oil pressure is low.
If you do, your engine can become so hot that
it catches fire. 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.
Low Oil Level Light
The engine is equipped with
an oil level monitoring
system. When the ignition
key is turned on, the
LOW OIL light will
come on briefly.
If the light does not come on briefly, have it fixed 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 ªEngine Oilº in the Index.)
If the light does not come on briefly, 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.

2-74 Change Oil Soon Light
The CHANGE OIL SOON
light should come on briefly
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 ªEngine Oil, When to
Changeº in the Index. To reset the CHANGE OIL
SOON light, see ªOil Life Systemº in the Index.
Security Light
The SECURITY light will
come on when you turn the
key to START and stay on
until the vehicle starts.
It will also flash if your ignition key is too dirty or wet
for the PASS
-Key
II system to read the resistor pellet.
See ªPASS
-Key IIº in the Index.
If the resistor pellet is damaged or missing, the light will
come on.
Cruise Light
The CRUISE light comes
on whenever you set your
cruise control. See ªCruise
Controlº in the Index.