2016 Prius 1) Water Pump codes, 2) HV battery (new) not charging up

I have a 2016 Prius with 193000km. I live at the bottom of a 'long' hill. At about 90000km+ long ago, the water pump and coolant was replaced as indicated by a warning light. As the vehicle aged, the battery deteriorated over time; thus well before the bottom of the long hill, the battery becomes fully charged sooner than when the vehicle was newer and the engine starts revving earlier as the battery aged. The battery level has also been acting strangely over the last year giving swinging levels of charge readings.

In December, a warning light lighted up again at about 190000km. The mechanic noted by the codes changed the water pump, a certain valve, and coolant. It was reset. All was fine until a month later, a warning lighted up again. The coolant for the engine and the inverter stuff are noted to be circulating, but the code for the water pump and a certain valve remain. There is no leakage of any coolants with use noted now, as different from the problem of other people here on the forum.

And since January, the car hybrid battery has stopped charging up, giving me at most 3 levels of use briefly. A new hybrid battery two days ago was put in: without any change now giving me a constant 2 levels of charge forever whether driving, idling at the lights, etc. There are no other codes, noted by different mechanic's reader.

I am driving around without the engine overheating as checked by the mechanic, without any warning light on the dashboard. But codes for water pump and that certain valve remain. And the hybrid battery stays at 2 levels of charge wherever or however I drive. Now with the new hybrid battery, the car is not revving so much as with the old battery at the bottom of the hill, but it is not charging up either.

Any suggestions?

 

Double checked with the mechanic, it is the P268111 code now.
And with a very stable and constant 2 bar hybrid battery level whichever way I drive it, not any lower nor any higher.

 

The new battery is now always a very confident 2 bar levels from bottom, vs the sometimes not so confident 2 bars dropping to 1 bar in the old battery. So confident that at times at traffic lights, it deems itself has enough power to shut off the engine til it thinks it doesn't.

Confirmed, it is the P268111 code only now.

The battery is new from genuine Toyota parts: the correct type (NiMHMM-X. R/TMC 2404) from Primearth EV Energy Co., Ltd. sourced by the independent mechanic with experience in Priuses of the different generations.

I live at the bottom of a long hill, ie to get home I have to descend a hill for about 5km for 5mins. I don't use B to get home as if I am at three bars at the top of the hill, the battery fills up to full just about it gets to the bottom of the hill when the car was new. Pulling into the driveway, as the battery is somewhat full it seems to want to use the engine as braking as if in B mode since the battery is full. If I were to use B mode getting home, it would also fill up the battery equally and use the engine as braking the whole way making the journey very noisy. To achieve the three bars at the top of the hill, I usually ease off the accelerator to gently go the last part of the hill to use the battery somewhat before descending home.

I am beginning to worry it is a particular computer module that we don't know of that's causing the P268111 code and or causing the new hybrid battery not charging up normally. The fuses are all fine. The coolant levels are normal without loss. The new water pump seems to be working. The car does not overheat with daily driving usage. And there is no warning light on the dash.

Thank you for all your questions.

 

The current troubles began in December when I was stuck in a traffic jam, when all of a sudden the car decides to not want to charge up the hybrid battery and at that very moment giving the warning light on the dash.