Codes help

What is the car doing that you don't like?

Was the water pump from Toyota? There are a lot of knockoffs that fail quickly.

 

Well, more than one thing, some of which I would not put off investigating, and some things that don't concern me. 12.55 volts at the aux battery would not concern me.

P261B indicates a problem operating the water pump, whether it was recently replaced or not. The troubleshooting for that code should be done, so the cause can be found and fixed, whether the cause is the pump itself or not.

B1503 indicates a suspect reading of the coolant temperature after the exhaust heat recirculation system. The code is saying a reading was seen that might be bogus because of how hot it would be if it were real. It could be a wiring issue. But in the context of having a water pump trouble code too, it could also mean a real reading that was as hot as it looked. That wouldn't be good.

P0A94 is a problem with a component of the inverter. It may be covered by a Toyota customer confidence program you can read about ➡here⬅.

The U codes report communication problems on the network that interconnects different ECUs in the car. They are tricky to troubleshoot; the details are in the "multiplex communication system" sections of the repair manual:

Toyota Service Information and Where To Find It | PriusChat

I would also want to put some priority on troubleshooting that, because, of course, the ECUs in the car are meant to communicate with each other for a bunch of reasons, and there are a bunch of things that might not be happening right if they can't. The communication problems could also mean that your scan tool might not be able to reach all of the ECUs that might have other trouble codes to tell you about. You don't really want a car where the ECUs aren't able to talk with each other.