The Fastlane

Mercedes calls their unit a “Flexible Service System”. The FSS on some Mercedes vehicles monitors actual oil quality as well as operating conditions (such as the number of cold starts, average engine temp, mileage driven, oil sump level, rpms, etc.). To measure oil quality, there is actually a sensor that measures the electrical conductivity of the oil. The higher the conductivity of the oil, the greater the need for an oil change, according to Mercedes. Of course, this isn’t likely a perfect model, and will not be nearly as accurate as an actual oil analysis in determining true oil quality, but it is better than no measurement at all.