P3000: ECU or HV battery failure? 2006 Prius

First post! 2006 Prius, 128K miles. Recently ran P0A80 and P3016 codes, battery showed signs of failure (running up and down charge while driving) and we decided to temporarily "band-aid" with a module replacement. The reason for band-aiding is because I don't live in this area, and most replacement packs here only cover a regional radius. I was hoping to drive home, and then replace if necessary.

One module was obviously out of whack, which we replaced. First test drive after replacement went great... for 10 miles. Then all error codes from before popped up: red triangle, check engine, ((!)), VSC. Back to limp mode. But the battery charge was displaying no change onscreen: it stayed at about 3/4 full, in the blue.

When we got home, we reopened and tested voltages. Everything was perfectly in line—range of 8.14-8.16V for all 28 modules. Took out 12V battery to do this; when we put it back in to drive to Autozone for diagnostic codes, we drove for 10 minutes beautifully again—no vacillation in battery charge—and then the same warning lights kicked on. Autozone's diagnostic equipment pulled up no codes at all. We began to think that, beyond the HV battery, there is likely a problem either with the computer, or the 12V battery, or both. Previously when my 12V started to fail, I had a blank dashboard issue (known issue for gen 2 prii, but it resolved after the 12V was replaced).

Today I took it to the dealership which pulled up codes P3000 and P3023. They also ran voltages & resistances on the 14 blocks. Voltages ranged 16.32-16.41V. Resistance range was 0.023-0.026 ohm, with exception of block 13, which showed 0.035. I'm assuming that's why P3023 came up.

My question: Does this variation in resistance seem confirmation enough that I should replace the whole hybrid battery pack (granting that the first codes were confirmation enough, but that I was hoping for a short-term fix, for reasons above)? Would it be wise to continue trying to test computer and/or 12V systems, to rule out those as possible causes of the P3000 code? And if so... how?

 

Belated thanks for this reply! Alas, I already changed the whole battery....