Really, the only thing to do is have the fault memory checked. You may have a control unit taking a dump (it happens alot). If you have any warranty, definitely take it in.
Dwarf, I would take it back and have the dealer check the faults and perform a test plan on the system. They shouldn't charge you since they misdiagnosed it. I am curious how many miles you guys have on your cars???
__________________ STETT Performance -
921 J Place, Suite 200
Plano, TX 75074
OEM Repairs and Maintenance
Extended Warranty Service
Everything Performance (brakes, turbos, Nitrous, Cams, Complete Engines, Clutches/Flywheels etc)
STETT Performance Official Grand Opening BMW Meet, May 6th 11A-3P -- Music, Food, Drawings and Tons of BMW's go to http://188.8.131.52/stett
and register.. it's FREE