2010 Prius with Code P0A03

Hello everyone, new to this Chat, So I've had my 2010 Prius for about a year now, bought it used and just recently just installed a low, mileage Motor, caused the previous one keep on rattling on start up and blew a rod on the highway, after installation have had to install new compressor, shorted out and last night while driving I got Check Hybrid system light and ABS warning indicator on, scan for code P0A03, Coolant Temp Circuit High, I need some direction and help, love my car, but I'm starting to dump too much money into it.

Please advise