2004 Buick Century Owner's Manual - Page 143

Change Engine Oil Light The CHANGE OIL SOON light should come on briefly as a bulb check when the engine is started. If the light does not come on, have it serviced. Security Light The SECURITY light will come on when the key is turned to START, and will stay on until the vehicle starts. 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)" under Engine Oil on page 5-13. To reset the CHANGE OIL SOON light, see "How to Reset the System" under Engine Oil on page 5-13. It will also flash if the ignition key is too dirty or wet for the PASS-Key® II system to read the resistor pellet. See PASS-Key® II on page 2-17. If the resistor pellet is damaged or missing, the light will come on. 3-41