Technical service bulletins are instructions a manufacturer sent its dealers about a known fault. They are not recalls and the work is usually not free, but they are the clearest signal of a problem the manufacturer already knows about.
SB-P-047527
Service Bulletin/Repair Instructions
MERCEDES: PARKTRONIC INTERMITTENTLY NOT FUNCTIONING. THE FUNCTION WORKS AGAIN AFTER A SHORT TIME OR DISTANCE. WHEN THE FOOT OPERATED PARKING BRAKE IS APPLIED, THE PARKTRONIC SYSTEM IS DEACTIVATED. IF THE FOOT OPERATED PARKING BRAKE IS ON AT THE FIRST NOTCH, THE CONTACT SWITCH MAY REACT WITH A CONSIDERATION DELAY WHEN THE PARKING BRAKE IS RELEASED. NO MODEL YEARS LISTED. *PE
TSB-42-10-109
Service Bulletin/Repair Instructions
MERCEDES: CORROSION PROTECTION COATINGS FOR BRAKE COMPONENTS AND HARDWARE MAY BE DAMAGED AND OR STRIPPED AWAY IF HIGHLY CONCENTRATED ACID BASED CLEANERS ARE USED. ONCE THE CORROSION PROTECTION IS DAMAGED OR REMOVED THE BRAKE COMPONENTS AND OR HARDWARE CAN BEGIN TO CORRODE. INCLUDE ALL MODELS AND MODEL YEARS. *PE
SSIMBNA1412A
Service Bulletin/Repair Instructions
EMISSION TESTING ON DYNAMOMETER. *YC