I run the full diagnostic on my 2000 S430 (155000 Mls). During the diagnostic the ignition is on and I hear the buzzing vibrating noise from the air intake side. Using the stethoscope, I could pinpoint to the airflow sensor/air intake area. No error code showing for the engine diagnostic. I’m just cautious and try to prevent any road side breakdown. Since the air intake regulation is with "fly by wire" is there an electric motor to adjust the air intake valve?