You way the door buttons don't work. I assume you mean the ones on the outside of the car, on the door handles of the front doors? You probably know these are meant only to unlock the doors, not lock them. You have to have the key fob within distance of car for them to work. You mention they do not work with the key fob too. This COULD be simply that the battery in the fob is dead. See if other functions of the fob work (try the remote start for example). If not, then your trouble is the battery needs changing in the fob. Now if it is NOT that situation go to your radio screen and select settings. Then vehicle. Search around and you will find a section on "door locks". For some reason the previous owner may have changed the settings and it does not allow the door handles/fob to operate the doors. If all this fails, time for the dealer.
