What does it mean when the service vehicle soon light comes on for a 2001 Chevy cavalier?

The "Service Vehicle Soon" light (sometimes just "Service Engine Soon" or a check engine light shaped like an engine) on a 2001 Chevy Cavalier indicates that the car's onboard diagnostic system (OBD-II) has detected a problem. It doesn't tell you *what* the problem is, only that one exists.

The problem could range from something minor (like a loose gas cap) to something more serious (like a failing sensor or catalytic converter). You need to get the diagnostic trouble codes (DTCs) read by a mechanic or using an OBD-II scanner. This scanner will give you a specific code(s) that will pinpoint the issue. Ignoring the light could lead to further damage and potentially expensive repairs.

Trying to guess what's wrong based solely on the light coming on is unreliable and could lead to unnecessary expenses replacing parts that aren't actually faulty. Get it scanned to determine the real problem.