Prius 2011 - P0A7F

Hello everyone! My first post here The forum is great, learned a lot of useful tips and tricks - thank you!
But now I have a problem with my Prius. About every 600-700 miles the "Check hybrid system" message is displayed and when I read the DTC, there is only one stored - P0A7F. If I don't clear it, it disappears after 3-4 starts of the car.
When the message is shown on the screen, the car drives absolutely normal - it starts and stops the ICE, it runs on battery, accelerates fine, etc. The only thing that I cannot turn on is the EV mode.
I've changed the 12v battery, the original one was not holding the proper voltage when tested under load. I bought regular 44Ah lead-acid battery, which is not very strong under load, but it keeps fairly good voltages. Well, my happiness ended about 1000 miles after the change with the same message, same DTC. So I plugged the Techstream and asked a friend to make screenshots when accelerate and breaking.

What do you think, do I need to change cells 6 to 9? The car has 168k kms on it, its roughly 105k miles.
I know I'm attaching TOO much screenshots, but I hope they can illustrate more completely the situation. Their names are the states when they're taken.

Thank you!

 

For someone with the same problem, here is the other topic with a discussion about a strange behavior after the DTC clearing: https://priuschat.com/threads/charges-for-10-seconds-and-stops-battery-cycle.180180/unread

 

Hello,
It was an awful situation where I didn't have bad modules, but weak ones so I decided to look for a full battery replacement, not individual modules.
I found a full battery pack with all of the cooling, cells and electronics from 1y/o crashed CT200h with less than 20k miles on it. It was a real bargain so I didn't think much. It's 2 years since and there're no signs of problems where temperatures here are between -20*C to +40*C (winter / summer).

You can try to test it with "Hybrid Assistant" Android app as it's described on their website to see which modules are weak.