Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
Are you using a basic hand scanner for OBD faults? If so, they typically only read engine OBD faults and nothing associated with BAS/ESP system. If the malfunction light is on, there most definitely is a fault some where.
If the only access you have is to a basic OBD scanner, then a shop (not necessarily a dealer) will have to at least pull fault codes for you.
If you have a shop pull fault codes for you, I can assist you in the diagnostic.
Yes, I'll be available all week. Good luck!