Wouldn't be the first time the dealership was telling customer complete BS assuming that they don't have a clue in order to either get out of a warranty repair or to inflate an invoice.
Also dealerships not having a clue is not rare either. Many garages these days only connect a computer to the diagnostics port, download whatever error codes are shown and tell the shocked driver that half of their car is kaputt with the repair likely going to be several thousands of euro.
All the while the real problem is a blown fuse for one of the control units or a wire has chaffed and broke somewhere - and the diagnostic codes come only because the ECU can't talk to some sensors because part of the vehicle's CAN bus is down.
