I had to have the Trans Valve body/trans control module/ Control solenoid(one part) replaced recently for a little over $1300 (the part was just under $800), 150K miles. Yellow code light came on and Transmission went into what I can only describe as "Fail safe" mode, took it to the dealer, like 4-5 transmission codes.

Luckily they have a hybrid/electric Guru at the Chevy dealer I go to, he properly diagnosed it and repaired it without just saying the transmission is shot. He also connected it to the GM mothership and updated all of the software which apparently took several hours. It does drive differently now with a few subtle but noticeable changes and better MPG. One big change is it will go into V4 under light load all the way up to the speed limiter, it previously would rarely if ever go into V4 over 65 MPH.

 

Wow, you did get some updates from the Borg Mothership.

 

I have no idea-lol, That's what the mechanic told me. He said he updated & reprogrammed the software, he connected it to the GM computer and it took several hours(unattended).