Right after my 75k service, I had the same thing happen on my 97 C230. Without an expert diagnosis by reading and interperting the codes, you'd be guessing what the problem is.
My independent shop pulled the codes and replaced the MAS. I was bummed that the part was not covered on my warranty but happy that the problem went away.
My understanding of the issue is that it's incredibly common and basically nothing to worry about. That particular part is basically a "wear" item that gives up after a while.
1988 300 SL (5 Speed)
1994 E320 Wagon