P0aa6 613 code

yesterday my prius got p0aa6 613 code, it still drives the same, i can start ir again after i shut it down. After i erased the code it came back after about 5miles. As i understand its transaxle problem. But its giving me orange warning light check hybrid system. Is it common when transaxle goes bad that the code is not permanent? Im hoping maybe its just loose wire somewhere. Any thoughts would help. Thanks.

 

Checked the wires on the inverter and main wires on the battery, no corrosion, not loose.

 

Another update. Drove about 10miles again, didn't get any code, but noticed that when i shut my car of, and turned ignition on, torque app showed aux battery lowest voltage 10.5v. Which i think after 10mile drive is very low. Ill just hope its aux battery fault and try to replace it next week.

 

Used multimeter on battery terminals , 40min after car was parked.
Everything off - 12.13v
Acc off lights on - 11.63v
Acc on lights on - 11.59.
Not sure if its normal on prius, but from my experience with cars that were not hybrids i think its low.

 

Little update, got no codes for almost a week, then got the code again, ordered new 12v battery and swapped today. Old battery was 20ah, made in 2014, leaking and wrong type. So im happy i decided to start with the battery first.

 

Photo of how old battery looked like.