What does the Service Engine Soon light mean in your 1993 Buick Century Sedan?

In a 1993 Buick Century Sedan, the "Service Engine Soon" light (sometimes spelled "Check Engine" on some models of that year) indicates that the car's onboard diagnostic system (OBD I, a very basic system in that era) has detected a problem. It doesn't tell you *what* the problem is, only that one exists.

The problem could be something minor, like a loose gas cap, or something more serious, like a failing sensor or a problem with the engine's emissions system.

To find out what's causing the light, you need to have the car's computer system scanned for trouble codes. A mechanic can do this using an OBD I scanner. Auto parts stores often offer this service for free. Once you have the code(s), you and/or a mechanic can determine the specific problem.