A TSB is a bulletin that Benz uses at the dealers when a proplem has come up, they are to check each car of that model only when the car is in their shop for service..if , in the check, they find that problem does exist, they do the recommended TSB free of charge ..the customer may not even know it was done. But there ar
e limitations.....
One of the dealer Techs will have more info on it and may post shortly..

You can find those tsb's on google