My 89 C4 coupe 's service engine soon light comes on. I changed the oil and filter and tryed to turn off the light. I pumped the brakes with the key on engine off. The light gos off for a short time then comes back on. How do I turn it off the light?

If anyone wnts to know. I bought a computer tester and checked out the system. Bad O2 sensor so I changed it and all is well in Corvette land.:D