Cadillac 1994 DeVille Owners Literature page 148

Engine Oil Light (Canadian Only)
This light tells you if
there could be a
problem with your
engine oil pressure.
The light goes on when you turn your key to "Run" or "Start." It goes off
once you start your engine. That's just a check to be sure the light works.
If
it doesn't, be sure to have it fixed so it will be there to warn you if
something goes wrong.
When the light comes on and stays on, it means oil isn't going through
your engine properly. You could be low on oil, or you might have some
other oil problem.
NOTICE:
Damage
to
your engine from neglected oil problems
can
D e
costly and is not covered by your warranty.
135