Issue with p1121, heat works fine

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!

 

The old inverter pump went bad and it was blowing the am2 fuse, so I replaced it and got that fixed.

Not sure but according to my gf, she was getting the same p1121 code and the mechanic replaced a part called heater control valve, but I think its the same thing as the coolant control valve. They might have not replaced it with an oem part or if they didn’t do the bleeding process, would that cause the control valve to go bad? Like I said before, once in a while the red triangle and the engine light would appear and disappear after filling in some water. I was wondering if it would help to replace the coolant?

The catalytic converter was stolen and we replaced it with an aftermarket part from amazon together with the o2 downstream sensor, did we miss anything?

Thanks for the help!