Hi there,
The Diagnostic tool I use is Toyota Techstream chaps - its definitely the best & allows me to capture live data including cell unit voltages & internal resistances.
You need a laptop that is running the Windows XP 32 bit O/S then if you look on ebay you need to buy the mini VCI & software - if you are PC Savvy you wont have any problems getting it all to work,
Yes I replaced a cell module & rebalanced & reconditioned the entire pack together with my special system i designed & built myself.
I am happy to help
Richard