I have just over 1200 KM on my E70 4.8i and today the engine warning lamp came on for the second time. I took it in for service after the first time, as there were some other issues, but I forgot to ask what the cause was when I picked it up. Today it came on again while driving. Service was closed, but I got a hold of my sales guy who said that it could be a vast number of things, but that it should be OK to keep driving until the service dept. opens again next week.
Does anyone have any insight into this?

I already checked the fuel cap which I understand could sometimes be a cause.