Check engine light 2004 altima

The check engine light came on in my son’s 2004 Nissan Altima 2.5S, when we took it to the shop the codes showed that the problem was the oxygen sensor and the catalytic converter, upon further inspection both turned out to be fine. The shop then told us that the computer needed to be reflashed at the dealership. The check engine light was on for about 2 weeks, at the end the engine was running a bit rough and had lost some power. Could reflashing the computer cure this & what is the cost?

I am not sure of your shop’s thoughts. It would be helpful if you could give us the actual code format: P1234 There is not a code that says you have a bad converter and a bad sensor. You may but it may be other things as well.

Many auto part stores will read the codes for you for free!

Thanks, I’ll call the shop and get the actual codes.

Don’t let that mechanic / shop get away! Most shops would just want to replace those parts based solely on the included words (oxygen sensor, catalytic converter) appearing in the code descriptions. I’m guessing the trouble code is P0420.
Ask the shop the justification for the recommended engine computer flashing (reprogramming).

My son finally gave me the codes: P0420 & P1273