2008 Mercedes Benz S550 problems

ENGINE

I’m reporting a serious safety issue with the balance shaft sprocket in my Mercedes-Benz S550 (M273 engine, 273.968). This is a known defect that causes the sprocket to wear out far too early due to poor material design. When it wears, it throws off the engine timing, leading to check engine lights, rough idling, reduced power, and even stalling. In some cases, the engine can shut down while driving, which is a major safety risk. Thousands of people have experienced this exact problem, and it’s all over Mercedes forums, Reddit, and technical bulletins. Mercedes quietly updated the part in later models, which shows they knew the early ones were defective. Some people got repairs under warranty or “goodwill,” but most of us are stuck with thousands in repair bills for something that clearly shouldn’t have failed. This isn’t just a mechanical issue—it’s a safety concern. Imagine merging onto a highway or turning through an intersection when the engine loses power. That’s a real risk with this defect. Mercedes should be held accountable, and NHTSA needs to investigate and push for a recall before someone gets hurt or worse.

NHTSA complaint #11659570 — an unverified report by a vehicle owner.

ELECTRICAL SYSTEM

The contact owns a 2008 Mercedes-Benz S550. The contact stated while driving 40-50 MPH, the vehicle was shuddering intermittently. The contact stated that the failure recurred while at a complete stop. The check engine warning light was illuminated. The contact stated that the failure had been recurring intermittently. The vehicle was taken to an independent mechanic, where it was diagnosed that the wiring harness was causing an engine misfire. The mechanic related the failure to an unknown recall. The dealer was notified of the failure. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 40,000.

NHTSA complaint #11577423 — an unverified report by a vehicle owner.

ENGINE

The contact owns a 2008 Mercedes-Benz S550. The contact stated while driving 40-50 MPH, the vehicle was shuddering intermittently. The contact stated that the failure recurred while at a complete stop. The check engine warning light was illuminated. The contact stated that the failure had been recurring intermittently. The vehicle was taken to an independent mechanic, where it was diagnosed that the wiring harness was causing an engine misfire. The mechanic related the failure to an unknown recall. The dealer was notified of the failure. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 40,000.

NHTSA complaint #11577423 — an unverified report by a vehicle owner.

TIRES

We were traveling home and our TPMS indicated a tire failure. The PSI starting dropping rapidly. We took the tire off and found that only 4 " of rubber holding the back sidewall together on the tire. I then inspected the other tires on the car (which were purchased and installed at the same time) are showing signs of failure as well. All of the tires are 255-40-r19 We had a family of 4 in the vehicle at the time of the incident.

NHTSA complaint #11547224 — an unverified report by a vehicle owner.

POWER TRAIN

The contact owns a 2008 Mercedes-Benz S550. The contact stated while driving 35-40 MPH, the message "SAFETY" was temporarily displayed on the instrument panel. Additionally, the contact stated while starting the vehicle on several occasions, the message " SAFETY " was displayed on the infotainment system screen. The check engine warning light was illuminated, and the messages "Active Head Lamp Inoperative" and "Service Required. Do Not Shift Gears" were displayed. The contact also stated that upon shifting into drive (D), the gear shift indicator displayed that the transmission was in park (P). The contact stated that the vehicle failed to shift into the intended gear and had become undrivable. An independent mechanic replaced the battery; however, the failure persisted. The mechanic informed the contact that the computer needed to be reset. The vehicle was not repaired. The used car dealer was notified of the failure. The Mercedes-Benz dealer and manufacturer were not notified of the failure. The failure mileage was approximately 176,310.

NHTSA complaint #11541256 — an unverified report by a vehicle owner.

ELECTRICAL SYSTEM

The contact owns a 2008 Mercedes-Benz S550. The contact stated while driving 35-40 MPH, the message "SAFETY" was temporarily displayed on the instrument panel. Additionally, the contact stated while starting the vehicle on several occasions, the message " SAFETY " was displayed on the infotainment system screen. The check engine warning light was illuminated, and the messages "Active Head Lamp Inoperative" and "Service Required. Do Not Shift Gears" were displayed. The contact also stated that upon shifting into drive (D), the gear shift indicator displayed that the transmission was in park (P). The contact stated that the vehicle failed to shift into the intended gear and had become undrivable. An independent mechanic replaced the battery; however, the failure persisted. The mechanic informed the contact that the computer needed to be reset. The vehicle was not repaired. The used car dealer was notified of the failure. The Mercedes-Benz dealer and manufacturer were not notified of the failure. The failure mileage was approximately 176,310.

NHTSA complaint #11541256 — an unverified report by a vehicle owner.

VEHICLE SPEED CONTROL

P-RC-200808004 BODY CONTROL ACCELERATION SENSORS...MODELS 2001-2008 11/4/2008 - 200807001 RE-CODE THE SOFTWARE CALIBRATION NUMBER (SCN) 11/04/2008 - 200803005 REPLACE FRONT SAM S-SC-2012070002 RETROFIT ADAPTER WIRING HARNESS ON CAMSHAFT ADUSTMENT SOLENOIDS MODELS 2005-2011 S-RC-200807001 REVISION TO STEP Z, IN WORK PROCEDURE RECODE THE SOFTWARE CALIBRATION NUMBER (SCN).

NHTSA complaint #11324288 — an unverified report by a vehicle owner.

WHEELS

EVEN CHANGE TO NEW TIRES, THE AIR PRESSURE UP TO 37 AND ALWAYS AFTER 1 WEEK OR SO, DOWN TO 33, COMPLAIN AND CHANGE TIRE AND STILL HAVE THE SAME RESULT. YOU COULD ONLY CHECK THE TIRE PRESSURE AFTER YOU RUN FOR A WHILE. MASSAGE CHAIR, AFTER OPERATION AND ALL THE SUDDEN IT STOP. CLOCK IN THE CABIN DOESN'T CHANGE EVEN YOU SET IT UP AND THE INTERNAL SAID THE RIGHT TIME AND THE FRONT DOESN'T CHANGE

NHTSA complaint #11292448 — an unverified report by a vehicle owner.

UNKNOWN OR OTHER

EVEN CHANGE TO NEW TIRES, THE AIR PRESSURE UP TO 37 AND ALWAYS AFTER 1 WEEK OR SO, DOWN TO 33, COMPLAIN AND CHANGE TIRE AND STILL HAVE THE SAME RESULT. YOU COULD ONLY CHECK THE TIRE PRESSURE AFTER YOU RUN FOR A WHILE. MASSAGE CHAIR, AFTER OPERATION AND ALL THE SUDDEN IT STOP. CLOCK IN THE CABIN DOESN'T CHANGE EVEN YOU SET IT UP AND THE INTERNAL SAID THE RIGHT TIME AND THE FRONT DOESN'T CHANGE

NHTSA complaint #11292448 — an unverified report by a vehicle owner.

ELECTRICAL SYSTEM

EVEN CHANGE TO NEW TIRES, THE AIR PRESSURE UP TO 37 AND ALWAYS AFTER 1 WEEK OR SO, DOWN TO 33, COMPLAIN AND CHANGE TIRE AND STILL HAVE THE SAME RESULT. YOU COULD ONLY CHECK THE TIRE PRESSURE AFTER YOU RUN FOR A WHILE. MASSAGE CHAIR, AFTER OPERATION AND ALL THE SUDDEN IT STOP. CLOCK IN THE CABIN DOESN'T CHANGE EVEN YOU SET IT UP AND THE INTERNAL SAID THE RIGHT TIME AND THE FRONT DOESN'T CHANGE

NHTSA complaint #11292448 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

MY VEHICLE HAS A STRONG GAS ODOR WHILE DRIVING BUT PARTICULARLY WHEN THE VEHICLE IS STATIC OR PARKED. THIS SMELL IS SO STRONG THAT I CANNOT SIT IN THE CAR AND MY CLOTHES REAK OF THE SMELL. THERE HAS NOT BEEN ANY EXTERNAL GAS LEAKAGE OR PERFORMANCE ISSUES WITH THE CAR. ONLY THE GAS ORDOR THAT HAS GIVEN ME A HEADACHE AND MAKES ME NAUSEATED. THE CAR ONLY HAS 70,000 MILES ON IT.

NHTSA complaint #11164448 — an unverified report by a vehicle owner.

SUSPENSION

I HAD TO REPLACE BOTH FRONT AIR SHOCKS AROUND 90,000 MILES. NO OFF ROAD DRIVING. BOTH AIR STRUTS LEAKED WITHIN 4 MONTHS . SUSPENSION WARNING LIGHT CANE ON FIRST. THEN A MESSAGE TO STOP THE CAR AND NOT OPERATE.

NHTSA complaint #11124439 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE

TL* THE CONTACT OWNS A 2008 MERCEDES BENZ S550. THE CONTACT STATED THAT THE VEHICLE HAD EXPERIENCED AN ABNORMAL FUEL ODOR. THE VEHICLE WAS TAKEN TO THE DEALER WHERE IT WAS DIAGNOSED THAT THE FUEL TANK WAS FRACTURED AND NEEDED TO BE REPLACED. THE VEHICLE WAS NOT REPAIRED DUE TO THE PART BEING ON BACK ORDER. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE CONTACT HAD REFERENCED NHTSA CAMPAIGN: 12V557000(FUEL SYSTEM, GASOLINE) AS A POSSIBLE SOLUTION TO THE FAILURE HOWEVER THE VIN WAS NOT INCLUDED. THE FAILURE MILEAGE WAS APPROXIMATELY 91,000.

NHTSA complaint #10956010 — an unverified report by a vehicle owner.

SUSPENSION

TL* THE CONTACT OWNS A 2008 MERCEDES BENZ S550. THE CONTACT STATED THAT THE FRONT END OF THE VEHICLE LOWERED, INDICATING THAT THERE WAS SUSPENSION FAILURE. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 70,000. UPDATED 09/01/15*LJ UPDATED 12/7/2015

NHTSA complaint #10730608 — an unverified report by a vehicle owner.

TIRES

I PURCHASED 4 NEW 255/45/ZR18 EXTREMECONTACT DWS ABOUT 13 MONTHS AGO AND NOW ALL 4 TIRES HAVE A BULGING BUBBLE ON THE SIDEWALLS. OF COURSE I BROUGHT IT BACK FROM WHERE I PURCHASED IT FROM AND THEY BLAME IT ON POT HOLES, ROAD HAZARDS. I CURRENTLY CANNOT DRIVE THE VEHICLE IN FEAR THAT I MIGHT HAVE A BLOW OUT. I HAVE PURCHASED MANY TIRES BEFORE THAT WERE NOT CONTINENTAL AND NEVER EXPERIENCED WHAT IM GOING THROUGH NOW. LET SEE HOW LONG IT WILL TAKE TO BE CONTACTED WITH SOME HELP OR WHAT EXCUSE THEY GOING TO COME UP WITH.

NHTSA complaint #10705489 — an unverified report by a vehicle owner.

TIRES

MICHELIN PILOT SPORT A/S PLUS 255/45ZR18 99Y AS+ INSTALLED ON 2008 MERCEDES S550. TIRES TREAD IS "CHUNKING" WITH 18,000 MILES OF USE. PURCHASED FROM COSTCO. I HAVE CONTACTED COSTCO. WAS TOLD IT WAS "NORMAL", COMPLAINED IT CANNOT BE, WE NEGOTIATED BACK AND FORTH ON AN ADJUSTMENT. IT WASN'T SATISFACTORY. I WAS OFFERED FOR A DISCOUNT PRICE THE "NEW" VERSION OF THE TIRE, I.E. PILOT SPORT A/S 3. I HAVE READ THE OTHER COMPLAINTS ON NHTSA SITE. THEY ARE SIMILAR TO MINE. I SPOKE TO 4 DIFFERENT COSTCO EMPLOYEES, THREE DIFFERENT MICHELIN YET, I COULD NOT FINE ANYONE AT COSTCO OR MICHELIN THAT CAN ASSURE ME WITH AN OFFICIAL MICHELIN STATEMENT THE PROBLEM HAS BEEN CORRECTED WITH THE NEW PILOT SPORT 3. I WILL NOT PAY TO HAVE NEW TIRES INSTALLED AT A DISCOUNT AND HAVE THE SAME THING HAPPEN AGAIN.THESE TIRES ARE A POTENTIAL SAFETY HAZARD.

NHTSA complaint #10574210 — an unverified report by a vehicle owner.

TIRES

THE TIRE TREAD ON THE MICHELIN PILOT SPORT A/S PLUS SHREDS OR CRUMBLES. MICHELIN CALLS IT "CHUNKING" AND SAID IT WAS DUE TO THE COMPOUND USED TO MAKE THE TIRE. THE COMPOUND HAS SINCE BEEN MODIFIED. THIS PROBLEM OCCURRED ON MY GIRL FRIEND'S 2009 MERCEDES C-SERIES SEDAN AND ALL FOUR TIRES WERE REPLACED IN OR ABOUT NOVEMBER 2012. I NOTICED THE SAME PROBLEM OCCURRING TO THE FRONT TIRES ON MY MERCEDES S550 AT JUST OVER 24,000 MILES OF USE. THE TIRE HAS A 45,000 TREAD-WEAR WARRANTY. THE TIRES WERE PURCHASED IN NOVEMBER 2010. THE MICHELIN DEALER AND MICHELIN ACKNOWLEDGE THIS IS A KNOWN PROBLEM. THE TREAD SPLITS OR CRACKS AT THE SIPES AND FALLS OFF, AFFECTING TRACTION AND POSSIBLY RISKING A CATASTROPHIC FAILURE. MICHELIN SAID THE PROBLEM OCCURS ON ONLY CERTAIN MODEL VEHICLES AND DOES NOT INTEND A RECALL. THESE TIRES WERE RECOMMENDED BY MICHELIN FOR MY VEHICLE, BUT IT APPEARS THEY MAY NO LONGER RECOMMEND IT. THEY NO LONGER RECOMMEND OR MAKE THEM FOR MY GIRL FRIEND'S VEHICLE.

NHTSA complaint #10537491 — an unverified report by a vehicle owner.

ELECTRICAL SYSTEM

I WAS IN UNFAMILIAR AREA. REMOTE KEY WOULD NOT OPERATE. WHEN USING SMALL KEY TO ENTER VEHICLE CAR SIREN WOULD NOT QUIT BLARING AND .NEW BATTERIES DID NOT HELP. MERCEDES RESPONDER TOLD ME I HAD INOPERATIVE "DEAD" KEY. CAR OF COURSE WAS INOPERATIVE. NO WAY TO MOVE CAR FROM AREA. COULD NOT SECURE CAR. I HAD RBM IN ATLANTA ON CELL PHONE ENTIRE TIME. ABOUT HOUR LATER SOMEONE TOOK ME TO MY HOME FOR SPARE KEY. THIS WORKED. KEY WAS AS MERCEDES RESPONDER TOLD ME...... DEAD. THE MERCEDES KEYS ARE UNSAFE AND UNDEPENDABLE. NEED TO BE RECALLED. MERCEDES WOULD NOT REPLACE "DEAD" KEY PER KYRUS FRAMES AT RBM IN ATLANTA. BECAUSE MY CAR HAD 57000 MILES ON IT AND OUT OF WARRANTY. KEY MUST BE RECALLED DUE TO SAFETY CONCERN THERE IS NO WAY TO OPERATE A "DEAD" KEY. MERCEDES RESPONDER TOLD ME THAT HE SEES IT ALL THE TIME. WHAT IF??? I HAD BEEN MILES FROM HOME? UNSAFE AREA? COMPROMISING SITUATION?THIS IS UNACCEPTABLE FOR $100,000 CAR. I COULD BE DEAD. JUST PROVIDE A WORKABLE KEY MERCEDES.

NHTSA complaint #10536999 — an unverified report by a vehicle owner.

EQUIPMENT ADAPTIVE/MOBILITY

I WAS IN UNFAMILIAR AREA. REMOTE KEY WOULD NOT OPERATE. WHEN USING SMALL KEY TO ENTER VEHICLE CAR SIREN WOULD NOT QUIT BLARING AND .NEW BATTERIES DID NOT HELP. MERCEDES RESPONDER TOLD ME I HAD INOPERATIVE "DEAD" KEY. CAR OF COURSE WAS INOPERATIVE. NO WAY TO MOVE CAR FROM AREA. COULD NOT SECURE CAR. I HAD RBM IN ATLANTA ON CELL PHONE ENTIRE TIME. ABOUT HOUR LATER SOMEONE TOOK ME TO MY HOME FOR SPARE KEY. THIS WORKED. KEY WAS AS MERCEDES RESPONDER TOLD ME...... DEAD. THE MERCEDES KEYS ARE UNSAFE AND UNDEPENDABLE. NEED TO BE RECALLED. MERCEDES WOULD NOT REPLACE "DEAD" KEY PER KYRUS FRAMES AT RBM IN ATLANTA. BECAUSE MY CAR HAD 57000 MILES ON IT AND OUT OF WARRANTY. KEY MUST BE RECALLED DUE TO SAFETY CONCERN THERE IS NO WAY TO OPERATE A "DEAD" KEY. MERCEDES RESPONDER TOLD ME THAT HE SEES IT ALL THE TIME. WHAT IF??? I HAD BEEN MILES FROM HOME? UNSAFE AREA? COMPROMISING SITUATION?THIS IS UNACCEPTABLE FOR $100,000 CAR. I COULD BE DEAD. JUST PROVIDE A WORKABLE KEY MERCEDES.

NHTSA complaint #10536999 — an unverified report by a vehicle owner.

POWER TRAIN

MERCEDES BENZ, S550, 4MATIC, 2008. I WAS STOPPED AT A RED LIGHT. WHEN THE LIGHT TURNED GREEN AND I WAS MOVING FORWARD AT ABOUT 15-20 MILES PER HOUR, THE CAR CAME TO A SUDDEN STOP. THE VEHICLE BEHIND ME ALMOST RAN INTO MY BACK SINCE THERE WERE NO BRAKE LIGHTS ILLUMINATED WHEN THIS UNFORTUNATE MALFUNCTION TOOK PLACE. I IMMEDIATELY LOOKED THE CONTROL PANEL FOR ANY MALFUNCTION ALARM AND THERE WERE NONE. THE ROOT CAUSE OF THE PROBLEM WAS FRONT DIFFERENTIAL SEIZE UP WITHOUT ANY WARNING. THERE WERE THE RIGHT AMOUNT OF OIL IN THE RESERVOIR SO THE PROBLEM WAS NO DUE TO LACK OF LUBRICATION. THE CAR WAS REPAIRED BY MB DEALER AND I WAS GIVEN A BILL FOR (HOLD ON TO YOUR PANTS) $8,252. I CALLED MB CUSTOMER SERVICE TO FIND OUT IF THERE ARE ANY RECALL ON THIS MALFUNCTION. I WAS TOLD NONE REPORTED. I HAVE A HARD TIME BELIEVING THAT I AM THE ONLY ONE WITH THIS PROBLEM. I ALMOST CAME TO A DECISION TO SIGN OVER THE TITLE AND HAVE THEM SELL THE CAR TO RECOVER THE REPAIR COST. OBVIOUSLY THE DEALER IS NOT AT FAULT HERE. HOWEVER YOU WOULD EXPECT THAT A CAR OF THIS CALIBER WOULD BE BETTER DESIGNED AND SUPPORTED. AS YOU HAVE GUESSED I AM UNHAPPY WITH MY MB. BY THE WAY IF YOU ARE TRYING TO SIGN ON FOR MB ONLINE OWNER COMMUNITY AND WANT TO CHOOSE THE USERNAME "UNHAPPY", YOU CAN'T. IT IS ALREADY TAKEN. TRY IT WITH SOME #S.

NHTSA complaint #10502393 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE

CAR STALLED WHILE DRIVING ON 10 FWY GOING FROM AZ TO CALIF. WOULD NOT RESTART & WAS TOWED TO PALM SPRINGS MBZ. NOT OPEN TIL MON 27TH.

NHTSA complaint #10408926 — an unverified report by a vehicle owner.

EQUIPMENT

I GOT A BLOW OUT IN THE REAR LEFT SIDE TIRE. I WAS DOING ABOUT 40 MPH AND DID NOT GO OVER ANYTHING THAT I WAS AWARE OF. I WENT TO CHANGE THE TIRE USING THE SUPPLIED TIRE AND JACK. THE JACK WAS VERY FLIMSY AND AFTER I RAISED THE VEHICLE THE JACK FLIPPED OVER CAUSING DAMAGE TO MY CAR, HOWEVER I NARROWLY AVOIDED PERSONAL INJURY. THERE IS A PLATE UNDER THE VEHICLE AT THE JACK CONTACT POINT WHICH ALSO BROKE OFF THE VEHICLE WHEN THE JACK ROLLED OVER. THE FOLLOWING ARE THE DEFECTS I BELIEVE EXIST. 1. THE JACK IS EXTREMELY FLIMSY AND IS DIFFICULT TO SET PROPERLY ON THE GROUND. 2.THE JACK PLATE ON THE CAR APPARENTLY IS ALSO NOT VERY STABLE. 3. THE HANDLE ON THE JACK IS VERY SHORT AND REQUIRES AN EXTREME AMOUNT OF STRENGTH TO LIFT CAR. (NO LEVERAGE) 4. THE LUG WRENCH IS ALSO VERY SHORT AND REQUIRES A LOT OF STRENGTH TO LOOSEN BOLTS, THERE IS ABSOLUTELY NO LEVERAGE. I ESTIMATE THE DAMAGE TO MY VEHICLE, WHICH I BLAME ON THE DEFECTIVE JACK TO BE ABOUT $750.00.

NHTSA complaint #10275658 — an unverified report by a vehicle owner.

SERVICE BRAKES, HYDRAULIC

I HAVE 2008 MERCEDES S550. THE CAR SUDDENLY STARTED MAKING NOISE IN THE FRONT AND I CALLED DEALERSHIP. THEY TOLD ME THE BRAKES ARE GONE AND EVEN ROTORS ARE DAMAGED. I HAD NO INDICATION ALL THIS TIME I WAS DRIVING THAT THE CAR HAD NO BRAKES AS NO BRAKELIGHTS CAME ON. TILL THE TIME I WENT TO DEALERSHIP NO INDICATION CAME AS SENSORS ARE NOT WORKING. IS IT NOT UNSAFE TO BE DRIVING ON THE HIGHWAY 60 TO 70 MILES /HR WITH NO BREAK SENSORS . I CALLED MERC AND THE TOP TWO PEOPLE ROBYN AND TIM IN ESCALATION DEPT TELL ME AT FIRST THEY ARE PICKING UP THE. REPAIR AND THEN TOTALLY TURNED THEIR BACKS AND YEARS AND SAID TO ME IT IS NOT A SAFETY ISSUE WHERE THE CARS BREAKS ARE COMPLETELY GONE TO THE POINT THE ROTORS ARE DAMAGED AND THERE IS MO INDICATION. WITH A 100K CAR WHICH HAS ALL THESE FANCY FEATURES BUT BRAKES ARE NOT IMO.

NHTSA complaint #10255933 — an unverified report by a vehicle owner.