I am getting the above-mentioned error in my Prius-Phv (2017). I got this error after doing the charging. However, if I drain all the batteries reserved for the plug-in part and then reset the error, the car works perfectly fine and the error never comes up and my car works like a normal Prius. Then I put my car into charging mode by pressing the EV/HV button. And after charging it up to 10%, I converted it to electric vehicle and the error show up again. So far what I have diagnosed is that this error only shows up when the car is running on Plug-in reserve batteries
If you're still concerned and want to know more about what happened when the code was originally set, you'll need to have techstream to do a through diagnostic to see if anything is still present in the ECU. If the car seems fine to you and you're not still concerned about why the code was set in the first place, I'd suggest writing down all the details you remember about the incident to keep as a reminder, if anything similar pops up in the future.
Check your wiring harness. See if something has been chewing on it. If you have the ability to toggle "on" the electronic cooling pump for the EV system - do it and verify it's pumping coolant. Also check coolant levels. The error indicates that the ECU doesn't know how fast or if the pump is spinning at all - bad signal wire, sensor or pump.
The same error appeared together with C1A63. I checked the wires, everything is ok. When I reset the error, it immediately appears again. The HV/EV, EV Avto buttons do not work. There are no arrows on the energy monitor showing the direction of energy. The car drives normally, there are no additional errors. The 12V battery is new. What could it be? Please help me