200K, runs GREAT, Battery great, Exclamation pt of death! Why?

Oh I don't know. You've got a 9 year old Prius with 200K miles on it.
I've said it before, Batteries are primarily a chemistry based component not a mechanical based component so to expect they will fail in the same manner, with the same type of warning usually given as a mechanical component wears out, isn't logical. So the reality that your Prius HAS been running great? Well most battery powered devices run well until the battery starts to fail.

If you are getting codes? Then I wouldn't bet against them meaning nothing.

I always look at this type of situation like an illness. You can feel bad (Get a Code or Notice an Operational Symptom) it might be nothing. It might just be a common cold and it goes away, you're feeling good...on with the show.

If it's something worse? You'll get sicker.

You've already evidently got codes designating a problem. You can hope they are a mistake, or hope they go away but the real situation or answer will reveal.

The most common refrain when people are hoping for a harmless ghost in the machine as opposed to The Monster of Hybrid Battery Repair or Replacement, is to check your 12 volt. Probably wouldn't hurt to do that.

Otherwise I suppose you have to run somewhere to get definition and validity concerning the codes your Prius is demonstrating. At 9 years and 200K the possibility that the Hybrid Battery is failing is real.

 

If the car does not demonstrate driveability issues then you don't have to run to the dealer. However, if you post the logged DTC then we can comment on their significance and what repairs are likely required.

 

yes. there are reman or salvage options, but neither has proved guaranteed reliability, so, you get what you pay for.

the reason your meter reads good is because one or more cells in the battery are starting to become imbalanced. the dealer can tell you which ones and how much. as patrick said, you can drive it in the meantime, but it's only a matter of time. how much time? no one knows. can you hear the battery cooling fan at all?

it would be a good time to check the 12 volt health as well. all the best!

 

This may not be a battery problem. It could be a HV battery ground leakage problem caused by the AC compressor. This can be checked by disconnecting the supply to the compressor. If the codes go away and stay away after clearing them (disconnect the 12 volt battery) it is the compressor.

John (Britprius)