Just checking to see if you got this resolved. I replaced the whole transmission with one from a junk yard (accident vehicle) and had some issues. Car would not crank no matter what we tried. We reprogrammed the transmission computer on the valve body in the hopes that was the problem but no luck. We then switched in the original transmission computer but still nothing. Finally we discovered that the bolts used to secure the high voltage wires on the side of the transmission were 3 different sizes and we mixed them up resulting in a high voltage short to the transmission casing from one of the bolts. We used the original valve body, with the original transmission computer on it and it fired up and ran perfectly once we corrected the bolt issue. That was 6 months ago and the truck is still running.

When we had problems, many people suggested the hybrid battery was dead but that was definitely not the problem.

 

Can you say how you reprogramming transmission module?

 

dealer will have the updates it will cost a bit of money... Do note if the update the system you might get a CEL for the high voltage battery if that system setting was changed

 

Thank you for answer. CEL? Can you translate?
We bought software from alcdelcotds

 

updates might contain improvements or optimizations to the software code

there could be a chance the Transmission controller harness wires got backed out if it's not shifting..

there is a TSB on that right here
https://static.nhtsa.gov/odi/tsbs/20...43829-6448.pdf
it's similar to the one below
Don't try and mess with it. you will have to take it back to the guy that did it so that part can be inspected


do you have any check engine light codes?

 

So after we replace whole transmission my tahoe start and running good.