Diagnosing bad PCM?

Recently started having issues with the PCM in my swapped truck its a 896 from a '00 silverado.
What started it was water getting into the red connector, shorted out the bank 2 o2 sensor (HPT as seeing 1600mv)
and HPT was having difficulty "finding" the VCM.
Got that fixed by taking it all apart and scrubbing both the PCM pins and the connector and it ran fine afterwards but HPT was still having issues connecting the the pcm.
Swapped out the Torque converter and flexplate 3 days later got it all back together and it was running GREAT.

Now It's reading 450mv on the bank 2 02 sensor, I tried swapping the sensors and same thing Searched for any wires that may have been smashed putting the transmission back in and nothing..
Tried reflashing a previous tune file thinking maybe it was a bad flash or something, issue persisted.
While trying to hunt the issue down I was having even more trouble getting HPT to connect, eventually got to where it wouldn't connect at all but the engine still runs and I'm assuming the only code it no activity on the O2.

Would it be safe to say the PCM may be toast?