If you run a normal scan, and check the DPF, and it shows high levels / % soot etc. and needs a regen, you need to finish the scan, and go out of diagnostics mode, and into DPF. This is what I did and it again checked and reported on the fill levels, and asked I wanted to do a regen. It then outlined the steps I would need to take to start the process. But thats as far as I went, as mine was not that blocked. But I thing that I read that MB have removed the ability to to a passive regen due to fire risk..could that be what has happened with your cars?? Mine seems to be regenning as normal anyway..when I check it, its always been fine ( Fingers crossed )