There are 3 owner-reported fuel system complaints for the 2012 Mercedes-Benz S-Classin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
There is a strong smell of fuel in the cabin. When I lifted up the rear seats, where the odor is coming from, I see a film of fuel around the fuel sending unit on the driver's side. I lift up the sound insulation and I see fuel that has leaked on total the top of the sending unit.
TL* THE CONTACT OWNS A 2012 MERCEDES-BENZ S550. WHILE THE VEHICLE WAS STATIONARY IN A PARKING LOT, THE CONTACT SMELLED FUEL FROM THE REAR OF THE VEHICLE. THERE WERE NO WARNING INDICATORS ILLUMINATED. ON SEPTEMBER 5, 2019, THE CONTACT WAS ALERTED BY SOMEONE OF A FUEL LEAK UNDER THE REAR OF THE VEHICLE. UPON INVESTIGATION, THE CONTACT ASSOCIATED THE FAILURE WITH NHTSA CAMPAIGN NUMBER: 12V557000 (FUEL SYSTEM, GASOLINE). THE CONTACT CALLED MERCEDES-BENZ OF ARROWHEAD (LOCATED AT 9260 W BELL RD, PEORIA, AZ 85382, (623) 815-3900) AND NOTIFIED THEM OF THE FAILURE. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE FAILURE MILEAGE WAS 86,000.
VEHICLE ENTERED LIMP HOME MODE WHILE ENTERING INTERSECTION. DEALERSHIP SAID CODES DID NOT INDICATE AN ISSUE AND COULD NOT REPRODUCE PROBLEM. ONLY ACTIONS TAKEN WAS A COMPUTER TEST AND ROAD TEST. AFTER LEAVING THE DEALER, THE VEHICLE ENTERED THE LIMP HOME MODE AGAIN THIS TIME ON THE HIGHWAY. DEALER THEN REPLACED TWO SENSORS AT THE TURBO. AFTER RETURNING THE VEHICLE TO ME, IT ENTERED THE LIMP HOME MODE AGAIN, ALSO WHILE DRIVING ON THE HIGHWAY. THIS TIME, DEALER REPLACED THE TURBO WHEN IT WAS BROUGHT BACK IN FOR REPAIR. THE VEHICLE STILL ENTERED THE LIMP HOME MODE AFTER THIS REPAIR. SO THE DEALER HAS ALSO REPLACED THE CATALYTIC CONVERTER. PROBLEM STILL PERSISTED AND CAUSED A HOSE TO RUPTURE. THIS WAS REPLACED AND THE PROBLEM STILL PERSISTS AFTER A MONTH OF TROUBLESHOOTING AND PARTS REPLACING.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026