replaced cam sensor next day light came back on on 2004 Hyundai Tiburon

I found a tiburon for sale but the guy told me his engine light was on and found out it was the cam sensor so he replaced it. then said the next day it came back on. is it worth buying or could there be bigger problems now because of that?

Asked by for the 2004 Hyundai Tiburon
Possible circuit to the sensor from the computer or computer itself. Will have to be checked out by a mechanic to be sure.
ok thank you.