Luz Check on Kia Cerato 2007

Good afternoon, along with greeting you request your help. I tell you ... after a rain, the "Check" light went on to me. My car is a automatic Kia Cerato, never had any problem. Even this. I took him to concession and scanned him. Throw "oxygen sensor," they changed them (both), he walked well, but turned on again. What can it be? I need your advice. I don't know what to do anymore. Thanks

Jorgechispin