Buick 1993 Skylark Owner's Manual page 114

Low Coolant Warning Light
If this light comes on, your
system is low on coolant
and the engine may
overheat.
Malfunction Indicator Lamp (Service
Engine Soon Light)
See "Engine Coolant'' in the Index and have your
vehicle serviced as soon as you can.
A computer monitors operation of your fuel, ignition
and emission control systems. This light should come o
when the ignition is on,
but the
engine is not running, as
a check to show you it is working. If it does not come on
at all, have it fixed right away. If it stays on, or it comes
on while you are driving, the computkr is indicating that
you have a problem. You should take your vehicle in for
service soon.