We got scammed. We brought my girlfriends Malibu in for a transmission flush and they said they would have to do a diagnostic first. Their " diagnostic " procedure solely included them reading the trouble code on the ECU. I can do this at home at zero cost , but they charged her over $100 for this with no other effort involved into the work they charged for. They seemed to shoot from the hip and somehow procured blame on the cat. converter . I brought the car to a friend who works at a dealer in Mesa who verified we got ripped off with the bogus diagnostic . Would not recommend and will never return .