Valley pan... What went wrong?

[fmugur]

I had a friend who changed the valley pan, manifold gaskets and so on for me. He never worked on BMW before but he is a good mechanic. After the the job was completed (although I still have the original leak and I will come back to this on a different thread) I got the Check Engine, DSC, ABS and Brake lighst on. I do not have an OBD II reader and I do not know the codes but I assume it must be something to do with some sensors/connectors that were disconnected during this procedure.
Do you know where should I look to solve this problem?
I checked the connectors I could whitout talking everything apart again.

[jst2878]

MAF sensor could be unplugged or the vacuum booster

[fmugur]

Thanks a lot. MAF was not plugged all the way in.