My check engine light came on code 0455 is it a big problem can anyone tell me

Yes I have. I don't know if it was a good idea I disconnected the battery for like 30 minutes went back and pluged it up and the light went away I took it for a spin to see if the the light would come back on but it didn't if it does I would buy a new gas cap see if that fixes the problem if not taking it to a mechanic hopefully is nothing major thanks for your help.