The grim reaper has finally arrived

After asking others more knowledgeable than me about OBD2 readers it appears that my original blame on corrosion was not accurate because too many systems are giving bad data and problem is with a bad OBD2 reader. However, the corrosion needs to be addressed as well, so OP's concern with addressing that is valid.

 

A little corrosion on the bussbars and nuts does not need to be addressed. If there is corrosion on the voltage sensing wires orange connector that plugs into the battery ECU, then that does need to be addressed, but I do not think that is the case based on the screenshot in post #13. What needs to be addressed in the OP's situation is the bad module in block #6.

 

I wouldn't trust those modules... What's more you only have one bad module not two and a common mistake people make is replacing both modules in a block when only one module is bad. This is a problem if your replacement module doesn't match your existing modules in age and capacity and if you replace both of those modules in the same block you're doubling down on the level of hassle you might create for yourself.

In my opinion professor Joe sells the highest quality replacement module because he's spent tens of thousands on lab grade testing gear several times over the past couple decades: Oregon's Trusted Hybrid Battery Supplier: 2nd Life Story

 

It might not hurt but its the source of corrosion that eventually ends up in the ECU and buying a new wiring harness with the link in my signature, will last way longer than just cleaning the corrosion in the ECU.