Cadillac 2002 Seville Owner's Manual page 169

Oil Life Indicator
This feature lets you know when to change the engine
oil. It's based on the engine oil temperatures and your
driving patterns.
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To see the display, press the INFO button several
times until ENGINE OIL LIFE appears. If you see
99% ENGINE OIL LIFE, 99 percent of your current
oil life remains.
The DIC may display a CHANGE ENGINE OIL
message. Always keep a written record of the mileage
and date when you changed your oil. For more
information, see "Maintenance Schedule" in the Index.
If you see CHANGE ENGINE OIL, it means the oil
life is gone and you should change the oil right away.
The system doesn't check how much oil you have,
so you'll still have to check for that. To see how,
see "Engine Oil" in the Index.
When the oil is changed, you'll need to reset the system.
See "Oil Life Indicator, How to Reset" in the Index.