First question are the codes p0410 & p0420 related in any way like will one cause the other etc. I do know what the codes are.

Second as far as p0420 I already changed the rear o2 and checked the wires so does this mean that its 100% my cat? I have no loss of power great gas mileage no studdering hard starts etc.

Third as for the p0410 is the air pump supposed to be quiet practically non noticeable. When I start the van I can hear the pump going for about a minute or so and it sounds kinda like a vacuum cleaner. I may have heard it screech once or twice in the really cold weather. I understand how the whole system works and how the valve can stick and everything but the valve looks to be brand new. So in question could the valve have been replaced and already left its damage. I don't believe I can hear my air pump the way I do on the van on any of my other vehicles but I figured with it being right there in the well it would be noticeable so how loud should it be..

 

Looking up the code on the net shows that you might have a problem with the check valves and not the air pump.

 

I had changed the check valve a few months ago and the light went away. It came back a few days ago but I think this time its the pump bc rhe pump was making s loud whine wjen it would run now I no longer hear it