The battery pack was showing signs of having problems soon after we bought it at 8 years old. Using the Hybrid Automotive conditioning system I got another 3 years out of it. It never threw a code but I replaced the pack with a new OEM one preemptively when we moved here in 2019. 115+*F summers are not friendly to batteries and I didn't want to take a chance on stranding the family in the middle of the Mojave Desert.
I got my 2006 this year (2020) for cheap because it was throwing an HV battery code. Turned out a cell was dead in a module. I checked the capacity of the other modules and found that most were around 3.5Ah by my measurements but replaced a couple that were considerably lower.
My story is exactly the same as Isaac. I bought my 2006 earlier in July because the original pack had a failed module at 160k. Got some replacements on ebay and chargers to cycle all the modules. Posted via the PriusChat mobile app.
I bought my Prius in 2004 and put about 190K miles on it by this past September, then the HV battery started giving me codes. About a year prior to that, I had noticed that the SOC indicator was changing faster than it had in the past, both discharging and recharging.
Bought used 2006 prius at 146k miles; carfax and dealer verification shows battery was replaced oem at 76k miles in 2014.
