2005 BUICK CENTURY oil reset

For additional information, see “When to Change
Engine Oil (GM Oil Life System)” and “How to Reset
the CHANGE OIL SOON Light ” 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 2-16.
If the resistor pellet is damaged or missing, the light
will come on.
Cruise Control Light
The CRUISE light comes
on whenever the cruise
control is set. See “Cruise
Control” underTurn
Signal/Multifunction Lever
on page 3-7.
Low Washer Fluid Warning Light
If the LOW WASH light
comes on when the
windshield washer paddle
is used, this indicates
that the uid is low
in the windshield
washer reservoir.
The light will also come on briey when the ignition is
turned on to show that it is working properly.
3-41

Notice:Use only engine oil identied as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certied For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.
GM Goodwrench
®oil meets all the requirements for
your vehicle.
If you are in an area of extreme cold, where the
temperature falls below−20°F (−29°C), it is
recommended that you use either an SAE 5W-30
synthetic oil or an SAE 0W-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Do not add anything to your oil. The recommended oils
with the starburst symbol that meet GM Standard
GM6094M are all you will need for good performance
and engine protection.
Engine Oil Life System
When to Change Engine Oil
Your vehicle has a computer system that lets you know
when to change the engine oil and lter. This is based on
engine revolutions and engine temperature, and not on
mileage. Based on driving conditions, the mileage at
which an oil change will be indicated can vary
considerably. For the oil life system to work properly, you
must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A CHANGE OIL SOON light will come on.
Change your oil as soon as possible within the next
two times you stop for fuel. It is possible that, if you are
driving under the best conditions, the oil life system
may not indicate that an oil change is necessary for over
a year. However, your engine oil and lter must be
changed at least once a year and at this time the system
must be reset. Your dealer has GM-trained service
people who will perform this work using genuine GM
parts and reset the system. It is also important to check
your oil regularly and keep it at the proper level.
If the system is ever reset accidentally, you must change
your oil at 3,000 miles (5 000 km) since your last oil
change. Remember to reset the oil life system whenever
the oil is changed.
5-16

How to Reset the CHANGE OIL
SOON Light
The GM Oil Life System calculates when to change
your engine oil and lter based on vehicle use.
Anytime your oil is changed, reset the system so it can
calculate when the next oil change is required. If a
situation occurs where you change your oil prior to a
CHANGE OIL SOON light being turned on, reset
the system.
After changing the engine oil, reset the system by
performing the following steps:
1. Turn the ignition key to RUN with the engine off.
2. Fully press and release the accelerator pedal slowly
three times within ve seconds.
If the CHANGE OIL SOON light ashes, the system
is resetting.
3. Turn the key to OFF, then start the vehicle. The oil
life will change to 100 percent.
If the CHANGE OIL SOON light comes back on
when you start your vehicle, the engine oil life
system has not reset. Repeat the procedure.
What to Do with Used Oil
Used engine oil contains certain elements that may be
unhealthy for your skin and could even cause cancer.
Do not 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 dispose of 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 threat to the environment. If you
change your own oil, be sure to drain all the oil from the
lter before disposal. Never 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.
5-17

If No Steam Is Coming From
Your Engine
An overheated engine warning can indicate a
serious problem.
If there is an overheated engine warning and you do not
see or hear any steam, the problem may not be too
serious. Sometimes the engine can get a little too hot
when the vehicle:
Climbs a long hill on a hot day.
Stops after high-speed driving.
Idles for long periods in traffic.
Tows a trailer.
If an overheated engine warning appears with no sign of
steam, try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL (N)
while stopped. If it is safe to do so, pull off the road,
shift to PARK (P) or NEUTRAL (N) and let the
engine idle.
2. Adjust the heater to the highest temperature and fan
speed settings and open the window as necessary.
If the overheated engine warnings no longer exist,
you can drive. Just to be safe, drive slower for about
10 minutes. If the warnings do not come back on,
you can drive normally.
If the warning continues, and you have not stopped,
pull over, stop, and park the vehicle right away.If there is still no sign of steam, idle the engine for
three minutes while you are parked. If the warning still
exists,turn off the engine and get everyone out of
the vehicleuntil it cools down. Also, see “Overheated
Engine Protection Operating Mode” later in this section.
You may decide not to lift the hood but to get service
help right away.
Overheated Engine Protection
Operating Mode
The overheated engine protection operating mode allows
the vehicle to be driven to a safe place in an emergency
situation. If an overheated engine condition exists, this
protection mode alternates ring groups of cylinders to
help prevent engine damage. In this mode, there will be
a signicant loss in power and engine performance.
The engine coolant temperature gage indicator will move
to the red area, and the engine coolant temperature
warning light will come on, showing that an overheated
engine condition exists. Driving extended miles (km)
and/or towing a trailer in the overheated engine protection
mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the
cause of coolant loss, change the oil and reset the oil
life system. SeeEngine Oil on page 5-13.
5-26

Scheduled Maintenance
When the CHANGE OIL SOON light comes on, it means
that service is required for your vehicle. Have your
vehicle serviced as soon as possible within the next
600 miles (1 000 km). It is possible that, if you are
driving under the best conditions, the engine oil life
system may not indicate that vehicle service is
necessary for over a year. However, your engine oil
and lter must be changed at least once a year and
at this time the system must be reset. Your GM
Goodwrench dealer has GM-trained service technicians
who will perform this work using genuine GM parts
and reset the system.
If the engine oil life system is ever reset accidentally,
you must service your vehicle within 3,000 miles
(5 000 km) since your last service. Remember to reset
the oil life system whenever the oil is changed. See
Engine Oil Life System on page 5-16for information on
the Engine Oil Life System and resetting the system.When the CHANGE OIL SOON light appears, certain
services, checks and inspections are required.
Required services are described in the following for
“MaintenanceI” and “MaintenanceII.” Generally, it is
recommended that your rst service be MaintenanceI,
your second service be MaintenanceIIand that you
alternate MaintenanceIand MaintenanceIIthereafter.
However, in some cases, MaintenanceIImay be
required more often.
MaintenanceI— Use MaintenanceIif the light comes
on within ten months since vehicle was purchased or
MaintenanceIIwas performed.
MaintenanceII— Use MaintenanceIIif the previous
service performed was MaintenanceI. Always use
MaintenanceIIwhenever the light comes on ten months
or more since the last service or if the light has not
come on at all for one year.
6-4

Scheduled Maintenance
Service MaintenanceIMaintenanceII
Change engine oil and lter. SeeEngine Oil on page 5-13. Reset oil life system.
SeeEngine Oil Life System on page 5-16.An Emission Control Service.••
Visually check for any leaks or damage.See footnote (k).••
Inspect engine air cleaner lter. If necessary, replace lter. SeeEngine Air
Cleaner/Filter on page 5-18.An Emission Control Service. See footnote †.••
Rotate tires and check ination pressures and wear. SeeTires on page 5-53.••
Inspect brake system.See footnote (a).••
Check engine coolant and windshield washer uid levels and add uid
as needed.••
Perform any needed additional services. See “Additional Required Services”
in this section.••
Inspect suspension and steering components.See footnote (b).•
Inspect engine cooling system.See footnote (c).•
Inspect wiper blades.See footnote (d).•
Inspect restraint system components.See footnote (e).•
Lubricate body components.See footnote (f).•
Check transaxle uid level and add uid as needed.•
Replace passenger compartment air lter.See footnote (g).•
Inspect throttle system.See footnote (j).•
6-5