P0A80 code but no check engine light

Good day all
I have a 2014 Toyota Aqua Japanese model S with 41,XXX kms on the odo. The car was a flooded car that i restored to using condition. The car had 28,XXX kms when i brought it flooded to which i had to buy a hybrid battery pack because the flooded one was dead. I brought it off someone who didnt know the kms the car that it came out of, but i believe it had alot of kms from the condition it was in. It lasted a year until some of the cells got bad and i had to replace them.
I did a live reading for the techstream software to determine which ones were bad and 2 cells in the middle was bad. I desided to to use some of the old cells from the flooded battery pack which some of them were good. How did i know, i did the charge and discharge test with a Skyrc imax B6AC v2 and got 2 good cells to replace in the newer pack. I balance the voltage to the other cells and put them in.
The cars fine no check engine light so i thought it was fixed. When i accelerate too hard or the battery gets too much load the engine stays on but no check engine light. When i do a scan it has the P0A80 code but no check engine light. I can reset the code by turning the car off and then back on again or clearing the code and then it goes back to normal. I have not seen anything on google or on this forum about this problem, i am hoping someone knows what is coulding this problem. Any advise would be helpful. Thank You

 

Before i replaced the cells there was a beep and two lights keep on for a P0A80 code, so the lights are not covered or removed. Yes, i would have to replace the entire pack in the future which would be an expensive repair but for now if i can get it work for a few months that would be good until i replace the pack. I was wondering could this hidden P0A80 code be because of a lose bus bar nuts?

 

I will try wd40 electrical contact cleaner on the ecu pins and report back.

 

I am from Trinidad in the caribbean

 

Ok I was able to fix my problem. It turns out that majority of the cells in the pack was bad. Only a few was ok so I instead of replacing the bad cells with the ones from the flooded pack, I decided to restore all the battery from the flooded pack and use the whole thing. I was about the restore all of them except one that was leaking giving me P0AA6 code so I replaced it with one from the bad pack that was good and the balance them. Now I get no phantom P0A80 and it holds charge longer as the car had 21,XXX miles when it was flooded meaning the pack was not used a lot. The voltages on all modules match (sometimes I get 0.1 volt difference on middle moduleswhen it is being drain)I don't know how long it would last but I am hoping it could last until next when I can afford a brand new pack.
I also have questions:-
Would the cell from the bad pack trigger the P0A80 code ?
At what voltage difference between modules would the P0A80 code be triggered?

 

There are no codes on the engine ECU only on the abs/vsc/trac ECU and a/c conditioner ECU, but I read somewhere on this forum that the P0A80 code is triggered when the voltage difference exceeds 1.3 volts I believe.