repairman54

Yes, Reach out to Chevy customer assistance number in your owner's manual. If your dealer can't fix it GM will refer you to another dealer and make arrangements. GM has a national technical assistance center to help dealers with difficult repairs. Some dealer techs don't fully utilize it.
Independent shops do not have this luxury of a shared national database or access to the engineers who designed these systems.
As a retired field tech. of 46 yrs. experience, I know that the factory backed tech as the most resources to solve an unusual issue IF they choose to use them.