I've got 3 codes that I would like some input on. The first one is P0404 and I've tried cleaning the egr valve but that hasn't seemed to help. Should I just buy a new one?

Next is P0481, the cooling fan circuit 2 malfunction. I've replaced the relay and even have a new cooling fan assembly. Still won't go away.

Lastly, P0753, the transmission solenoid. My fluid looks pretty decent but it hasn't changed yet.

I have a 2003 SS with almost 210,000 miles.

Thanks