2012 Mercedes-Benz S550 Problems
Owner-reported complaints filed with NHTSA, grouped by component
Data refreshed
What this page shows
Everything below is an owner-reported complaint submitted to NHTSA about the 2012 Mercedes-Benz S550, grouped by the component NHTSA recorded on the report. These are not confirmed defects, and they are not recalls. NHTSA does not verify most reports before publishing them, and a category with more reports in it is not evidence that a part is defective.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
Reports by component
Ranked by how many owner reports name each component category
- Engine337.5%
- Fuel system337.5%
- Electrical112.5%
- Steering112.5%
Percentages are of component mentions. A single complaint can name more than one component, so these do not sum to the total complaint count.
Each component in detail
What the reports in each category say, in the owners' own words
Engine
Reports naming the engine itself — including stalling, misfires, oil consumption, cooling and internal engine components.
From owner reports, verbatim
I purchased this vehicle in July 2020. I did a through check for recalls, warranty problems and could not identify any with this vehicle. From the get go the check engine light would come on. I checked the codes and they indicated an "electrical fault on bank 1, oxygen sensor 1. I replaced the wiring harness on that sensor as well as the sensor. From then until now the car would code weekly about the same issue. Eventually I started using a catalytic converter cleaner (it cleans off sulfur deposits) in an attempt to solve the issue. It would work for a couple of tanks of gas and then continuing coding. I asked MB on numerous occasions about what the issue was. They all said they had no idea. It looks to me like they knew what the issue was, but kept it to themselves. Several weeks ago I received a letter in the mail(not dated by postmark) but the letter was dated August, 2023. The letter outlined an issue with the catalytic converter system identifying my vehicle by vin. The same problem I have had all along. The letter came at a time when the car codes almost daily with the same issue as always, ONLY NOW THE VEHICLE STALLS occasionally while waiting at stop lights. I said great. I called to get an appointment to fix the issue only to be told that the fix window had passed. I told them that I just got the letter. They told me that the fix expired in December 2023. I called MB hotline at 1-800-367-6372 to see what was up. They said they would get back to me in 3 days. It's been a week so I called again and they advised me they can't help. It's an issue for the 2011, 2012, 2013, and 2014 MB S550 W221. Why is this not a recall and why won't they fix it. It's an expensive repair. They sent me the letter and said it was expired 6 months before I received the letter. Can you help?
VEHICLE CUT ON FIRE WHILE SITTING LUCKY OUTSIDE, THE CORNER OF ENGINE PASSENGER SIDE BELLOW THE HEADLIGHT STORES THE SUSPENSION AIR PUMP AND ELECTRIC HYDRAULIC STEERING PUMP.. BASE ON MY INSPECTION THE EHPS HEATED AND SET ON FIRE.SOMEONE SAW THE CAR ON FIRE AND CALLED FIRE DEPT.. CAR WAS LOCK AND STORE AFTER HOURS
Too few reports in this category for a page of its own — they appear in the full complaint list.
Fuel system
Reports naming fuel storage or delivery — tanks, pumps, lines, injectors and fuel leaks.
From owner reports, verbatim
I purchased this vehicle in July 2020. I did a through check for recalls, warranty problems and could not identify any with this vehicle. From the get go the check engine light would come on. I checked the codes and they indicated an "electrical fault on bank 1, oxygen sensor 1. I replaced the wiring harness on that sensor as well as the sensor. From then until now the car would code weekly about the same issue. Eventually I started using a catalytic converter cleaner (it cleans off sulfur deposits) in an attempt to solve the issue. It would work for a couple of tanks of gas and then continuing coding. I asked MB on numerous occasions about what the issue was. They all said they had no idea. It looks to me like they knew what the issue was, but kept it to themselves. Several weeks ago I received a letter in the mail(not dated by postmark) but the letter was dated August, 2023. The letter outlined an issue with the catalytic converter system identifying my vehicle by vin. The same problem I have had all along. The letter came at a time when the car codes almost daily with the same issue as always, ONLY NOW THE VEHICLE STALLS occasionally while waiting at stop lights. I said great. I called to get an appointment to fix the issue only to be told that the fix window had passed. I told them that I just got the letter. They told me that the fix expired in December 2023. I called MB hotline at 1-800-367-6372 to see what was up. They said they would get back to me in 3 days. It's been a week so I called again and they advised me they can't help. It's an issue for the 2011, 2012, 2013, and 2014 MB S550 W221. Why is this not a recall and why won't they fix it. It's an expensive repair. They sent me the letter and said it was expired 6 months before I received the letter. Can you help?
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.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Electrical
Reports naming the electrical system — wiring, battery, charging, control modules, infotainment and electrical accessories.
From owner reports, verbatim
I purchased this vehicle in July 2020. I did a through check for recalls, warranty problems and could not identify any with this vehicle. From the get go the check engine light would come on. I checked the codes and they indicated an "electrical fault on bank 1, oxygen sensor 1. I replaced the wiring harness on that sensor as well as the sensor. From then until now the car would code weekly about the same issue. Eventually I started using a catalytic converter cleaner (it cleans off sulfur deposits) in an attempt to solve the issue. It would work for a couple of tanks of gas and then continuing coding. I asked MB on numerous occasions about what the issue was. They all said they had no idea. It looks to me like they knew what the issue was, but kept it to themselves. Several weeks ago I received a letter in the mail(not dated by postmark) but the letter was dated August, 2023. The letter outlined an issue with the catalytic converter system identifying my vehicle by vin. The same problem I have had all along. The letter came at a time when the car codes almost daily with the same issue as always, ONLY NOW THE VEHICLE STALLS occasionally while waiting at stop lights. I said great. I called to get an appointment to fix the issue only to be told that the fix window had passed. I told them that I just got the letter. They told me that the fix expired in December 2023. I called MB hotline at 1-800-367-6372 to see what was up. They said they would get back to me in 3 days. It's been a week so I called again and they advised me they can't help. It's an issue for the 2011, 2012, 2013, and 2014 MB S550 W221. Why is this not a recall and why won't they fix it. It's an expensive repair. They sent me the letter and said it was expired 6 months before I received the letter. Can you help?
Too few reports in this category for a page of its own — they appear in the full complaint list.
Steering
Reports naming the steering system — racks, columns, power-steering assist and steering linkage.
From owner reports, verbatim
VEHICLE CUT ON FIRE WHILE SITTING LUCKY OUTSIDE, THE CORNER OF ENGINE PASSENGER SIDE BELLOW THE HEADLIGHT STORES THE SUSPENSION AIR PUMP AND ELECTRIC HYDRAULIC STEERING PUMP.. BASE ON MY INSPECTION THE EHPS HEATED AND SET ON FIRE.SOMEONE SAW THE CAR ON FIRE AND CALLED FIRE DEPT.. CAR WAS LOCK AND STORE AFTER HOURS
Too few reports in this category for a page of its own — they appear in the full complaint list.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Elsewhere on this vehicle
Data sources
- NHTSA Office of Defects Investigation — owner-reported complaints and the components recorded on them
Data on this page last refreshed .