'06, purchased in '08 w/ 6K miles. It's 24K now w/transmission locked limp mode

What is your question?

Trans locked in limp mode. Usually could reset by putting in park and restart engine. It's been happening since purchase but dealer said no trouble codes were found & it was returned to me after x3 (could not duplicate). Dealer relates it is a modulator/control board now, w/ MB proprietary codes so he can't fix it; it has to go to a MB dealer. My question: should not a MB get more 24K before transmission failure

What makes this problem better or worse?

driving

How long has your 2006 Mercedes-Benz SLK280 had this problem?

2008