help with p1121

Hey priuschat , I have Prius with 250k miles.Yesterday I replaced the inverter coolant pump, changed the coolant and did a bleed. I’m getting a p1121 and p0420 code. What steps should I follow to fix this issue. Should I directly replace the coolant control valve? Couple months ago the red triangle light would come on together with the engine light and would disappear after filling the radiator cap and the tank next to it with water. Thats what my girlfriend was told by the dealer she got the car from. It seemed okay back then but now it looks like a dumb idea, could this be related to the issue with p1121? Also, my car gets around 35-40mpg and AC works fine when turning to max heat. The radiatior cap is not hot, not sure if it has to be but thats what I remember reading it somewhere. I also checked the hose that go to the coolant control valve, all 3 hose are extremely hot. Also, there is another big hose above the coolant control valve which is extremely hot as well. I have attached a picture. When I do the vehicle signal check
mode on the screen, The battery voltage shows as 13.1V when driving. Thats all the info that I have for now. How should I troubleshoot, any ideas? and thanks in advance!

 

Thank you! I will try to get the air out. Since we filled the radiator with water should I change the coolant-water mixture by draining it? Also, I forgot to mention, the catalytic converter was stolen and we replaced it with an aftermarket part together with the O2 downstream sensor. Not sure if we forgot to replace anything else.