Possible Fix - Electronic Rear Axle Differential Lock Inoperative
I took it in and there was a recall to Update AMG Suspension Control Unit Software. I had this done and so far the message has not turned back on.
See notes on the recall, if you PM me your VIN I can run a VMI to see if your car has that recall open. The recall is not specific to that message but this update has fixed my dreaded message that kept coming on.
Mercedes-Benz ("MBAG"), the manufacturer of Mercedes-Benz vehicles, has determined that on certain Model Year (“MY”) 15-17 C-Class, E-Class, and GLC-Class (205, 213, and 253 platform) vehicles,
the software of the AMG suspension unit might not meet current production specifications. The possibility exists that noises may develop in the area of the rear axle differential.
An authorized Mercedes-Benz dealer will update the software of the AMG suspension control unit on the affected vehicles.



