Suspension Noise problems of the 2000 Mercedes Benz S500

Tl the contact owns a 2000 mercedes-benz S500l. While driving, the contact heard a knocking noise underneath the passenger side of the vehicle. The contact stated that the vehicle independently knocked while parked. The vehicle was taken to an independent mechanic where it was diagnosed that the air suspension was faulty. The contact was advised to take the vehicle somewhere else. The vehicle was taken to an auto center where it was diagnosed that the entire suspension needed to be replaced. The vehicle was repaired; however, the failure recurred. The abc active body control indicator illuminated and a message indicating to "stop the vehicle was too low". The vehicle was not diagnosed again or repaired. The dealer was not contacted. The manufacturer was not notified of the failures. The approximate failure mileage was 97,000.