Mark: I'd like to endorse ENGATWORK's suggestion that you have the alternator checked. Last summer I spent a week stranded in Las Vegas while the dealer puzzled over random fault codes in my E500. The car was in "limp home" mode and going nowhere...
The "technicians" couldn't figure out the problem 'cause the fault codes were wonky. They kept swapping parts in and out with no effect. Finally the service manager noticed voltage spikes and had the alternator checked. New part - problem gone!
BTW - kudos to M-B Roadside Assistance for giving us a Jaguar rental car and putting us up at the Sahara for the week
