There's a section for what to do without a techtream. After all, when the car is off, the brakes still work and pump the fluid. For those that want to use a techstream, the mini vci: www.amazon.com/gp/product/B00C9B32J4 Not sure if I'd violate any rules on posting where to find the software so folks are on their own for that.
I'm the original owner and the battery is still working fine. That said, my mom bought a 2007 with only 60K miles on it and it needed 7 cells replaced. Rebuilding that pack kept all 4 of my imax b6 chargers going for a solid week to suss out all the cells that were lower capacity. I also had to do a load test on each one to figure out the IR based on the voltage drop. But in general, I think it's rare for prius batteries to go bad unless there was a lot of pet hair in the cooling duct, driven in high temperatures without AC, or allowed to sit outside for years (summers) in 120 degree heat like in Phoenix. It's temperature that kills them. The Gen III use the exact same modules as the Gen II.