Need help!!!!!!!

[Prog8]

2008 g8 gt went for a drive car dies. Went to start and nothing. Nothing to starter at all. I’ve jumped pins to verify starter works and turns car over. Hooked scanner to it. No communication to ecm. Ordered a new ecm still the same result. Checked grounds checked fuses. Really has me baffled any help would be appreciated. By testing starter I know the charging system is up to par. It is procharged on e85 everything was fine all the sudden nothing. Starter doesn’t engage typical messages on dash. I was able to clear codes but still nothing no communication

[SpaceFrank]

I want to suggest checking the (hidden) fusible link in the large red 12v cable running up the driver's side of the engine compartment, but if you jumped it and the starter still turns over, that might not be your problem.