Error codes in my 2001 Toyota Prius

Hi Friends

I have a problem with my 2001 (135k miles) Toyota Prius Classic. The Hybrid warning lights came on last week and I reset the code/light.

It came back again today. When I do the scan following are the codes found :

P0420
P1430
P1431
P3191

I don't feel any difference while driving though...Could you pls suggest what is the best way to go about to clear this problem...

Thanks for your help ...