Management light gone out

[scott]

My engine management light had been on for a while, I had it diagnosed and it was something to do with the catalyc converter I have not fixed it yet but had my sports exhaust taken off and replaced with a standard one, I did not replace the faulty cat, I notice yesterday the light has gone out, it still works as I check when I turned the ignition on, is it possible just to turn its self off?

Thanks,