2011 Prius - P0AA6-613 Code

Morning everyone. My father-in-law recently gifted me a 2011 Prius with 250k miles and a blown engine (literally holes through both sides...) as a project car. Thanks to @Ragingfit it now has a new (used) Gen 4 engine in the bay. All is going well there minus the EGR flow code. Apparently I didn't get the EGR cooler as clean as I thought I did. Oh well, a project for another time.

My questions for now are in relation to the P0AA6-613 code that is now showing. I've done the research and know that it's tied to the transaxle or inverter. The code results in the Yellow triangle, a Check Hybrid System display, and a lack of cruise control. Despite these things, it still seems to drive just fine. It switches between battery and ICE with no difficulty at low speeds and seems to do just fine.

2 question:
- Do you assess that it's doing damage to drive it in this condition for the time being?
- Can anyone point me to any good instructions on narrowing the problem down to either specifically the transaxle or the inverter? Not looking to replace anything that I don't need to.

Thanks all.