2015 Chevy Silverado 1500 High Country PCM Issue (Likely)

[mengel]

I got a PCM error code after a big rainstorm.  So bad, that my vehicle wouldn’t start or turn over until I jumped it.  Battery tested fine, starter is in good working order, and code thrown was P0685.

 

I’ll cut to the chase.  It shifts rough half the time, always a different circumstance and gear.  I had it retuned because the stock tune felt like garbage (plus AFM sucks).  The TCM relearns after the first 200 miles and does alright-ish.  Then it’s like it just returns to crappy shifting, both up and downshifts.

 

 I’m worried the PCM and/or TCM might be toast since it’s not maintaining a consistent pattern.  I’ll drive with foot applying pressure on the exact same roads, speeds, and circumstances but it’ll shift roughly randomly - again, no consistency or patterns, just random bs.

 

Any help or advice would be greatly appreciated, thank you in advance