E92 2015 Tahoe L83 mated to a 2008 6L90E NO start

I have installed a 2015 tahoe engine mated to a 2008 6L90E from a silverado. I have tried to get this thing to run for a while now. I have played with VATS, Stater relay, Fuel pressure sensor and forget what else. I have never seen the injectors be activated or commanded ON at any point of this process. I have had to take a break from it out of frustration. Can it be that the T43 needs to be reprogrammed for a 2015 Tahoe? Or if there are any other ideas that people may have on this it could be helpful.

Thank you

I don't think the ecm and tcm will communicate properly. Do you have a DTC for that? I don't think that's the no start issue though. Can you post a copy of the tune file?

+1 the ECM and TCM are mismatched years, the protocols don't match.

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