RepairPal Certified shops can diagnose and repair your 2006 Cadillac CTS. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Go back to the dealer and have them reset your radio. They should do it for no charge (they should have done it before you paid them and took the vehicle away).
They did reset my radio now they say my radio screen circuit board is bad