The problem is back today. I went to start the car after stopping off somewhere and it would crank but not run again. I waited for 15 minutes or so and it ran fine again. My mechanic found another few codes stored in some sub-menus or something (sorry, I'm obviouly no mechanic). Here are the codes: B1040, B1041, B1042. B1040 is "CAN communication transmission to engine ECU faulty."

It stalled again right when I pulled into my garage, and then it had problems starting it again. I'm starting to believe that the smartkey might be the culprit since the mechanic did pull up an error code relating to the DAS something ME-SFI something (sorry, forgot the code number). It only stalls when the car is stopped, so is the car smart enough to know to shut off when it's not rolling? Thanks in advance.