ERROR codes ..? on 2003 Nissan Sentra

I brought a car and the check engine wont go out. I took to get inspected and it failed. I receive 3 error codes p0011 p0420 and I cant remember the last one but it has something to with the camshaft

1 answer
Take your car to a reputable repair facility and have a professional diagnosis done. Once that has been done, a proper explanation of the problems- and proper repairs- will prove beneficial.