There are 6 owner-reported powertrain & transmission complaints for the 2009 Mercedes-Benz C-Classin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
Rear Subframe gets rusted and breaks is an issue with most of mercedes c300 to the point the part is back order in USA and Germany its a safety issue and there should be a recall for it when I called mercedes benz they told me they get at least 3 to 4 calls a day about that issue and people can't find the part it's a comment issue and it sounds be resolved.
TOTAL 4 WHEELS LOCK AT HIGHWAY SPEED WITHOUT ANY WARNING. RECENTLY, A VERY UNSAFE INCIDENT HAS OCCURRED TO ME WHILE I WAS DRIVING ON THE HIGHWAY. I WAS DRIVING ON 202 SOUTH HEADING TOWARDS WEST CHESTER, PA NORTH OF EXIT 29; MY SPEED WAS ABOUT 50 MPH. ALL OF A SUDDEN THE CAR WENT FROM 50 MPH TO A COMPLETELY UNCONTROLLED FULL STOP WITH 1 TO 2 SECONDS. THE TIRES LEFT SKID MARKS ON THE ROAD. THE SEAT BELTS AVOID ME FROM BEING THROWN OUT OF THE CAR. I TRIED TO MOVE THE CAR IN ORDER TO AVOID TRAFFIC COMING AT ME AT 50 MPH BUT I COULD NOT. THE WHEELS OF THE CAR SUDDENLY LOCKED UP AND THE CAR COULD NOT BE MOVED. LUCKILY, THE CAR BEHIND ME WAS ABLE TO STOP WITHOUT ANYONE GETTING HEART. ALSO ALL THE INCOMING CAR AT THE HIGHWAY SPEED WERE ABLE TO SUDDENLY AVOID HITTING ME. THIS INCIDENT OCCURRED WITHOUT ANY WARNING OR ANY INDICATION THAT THERE IS A PROBLEM WITH THE CAR. THIS COULD HAVE BEEN A MULTI CAR ACCIDENT WITH POSSIBLE MAJOR INJURIES OR POSSIBLE FATALITIES. THE POLICE COULD NOT BELIEVE THAT THIS CAN HAPPEN AND THEY HAVE NEVER ANYTHING LIKE THIS BEFORE. THE CAR WAS TOWED TO THE MERCEDES DEALER. THE DEALER CALLED ME BACK TELLING ME THAT IT WAS THE SUDDEN FAILURE OF THE FRONT DIFFERENTIAL WITHOUT ANY WARNING. I CALLED MERCEDES AND THEY RESPONDED BY SAYING THAT THERE WAS A LEAK IN THE TRANSFER CASE. I INDICATED THAT THE CAR IS PARKED IN A GARAGE AND I WOULD HAVE SEEN THE LEAK FROM THE TRANSFER CASE. I WOULD LIKE THIS INCIDENT BE SERIOUSLY REVIEWED BY MERCEDES IN ORDER TO AVOID THIS FROM OCCURRING ON THE ROAD AGAIN AND BY THE DEPARTMENT OF TRANSPORTATION OR OTHER GOVERNMENT AUTHORITIES. AGAIN, LUCKILY NO ONE WAS HURT. *TR
TL* THE CONTACT OWNS A 2009 MERCEDES BENZ C300. THE CONTACT STATED THAT THE TRANSMISSION FAILED AND THE CONTACT WAS NOT ABLE TO CHANGE THE GEARS. THE VEHICLE WAS TAKEN TO AN AUTHORIZED DEALER WHO WAS NOT ABLE TO REPLICATE NOR DIAGNOSE THE FAILURE MORE THAN ONCE. THE VEHICLE STALLED ON MULTIPLE OCCASIONS AND WAS ONLY ABLE TO DRIVEN AT A SPEED OF LESS THAN 20 MPH EACH TIME THE TRANSMISSION FAILURE RECURRED. THE VEHICLE WAS TAKEN BACK TO THE AUTHORIZED DEALER A THIRD TIME FOR FURTHER INSPECTION, DIAGNOSIS AND REPAIR. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 41,000. UPDATED 09/15/14*LJ UPDATED 1/16/15 *JS
AT 43,500 AND 54 MONTHS THE TRANSMISSION IN THE CAR HAD TO BE REPLACED. THE CAR HAS ALWAYS BEEN PROPERLY SERVICED AT THE MERCEDES DEALER. I BELIEVE THIS MODEL/MAKE HAS DEFECTS AS I HAVE BROUGHT IT BACK FOR SERVICE MANY TIMES. *TR
TL*THE CONTACT OWNS A 2009 MERCEDES C350. THE CONTACT STATED THAT WHEN THE ACCELERATOR PEDAL WAS ENGAGED, THE TRANSMISSION SURGED FORWARD AT A HIGH RATE. THE FAILURE OCCURRED INTERMITTENTLY. THE DEALER WAS UNABLE TO DUPLICATE OR DIAGNOSE THE FAILURE. THE FAILURE MILEAGE WAS 15 AND THE CURRENT MILEAGE WAS 32000.
TL*THE CONTACT OWNS A 2009 MERCEDES BENZ C300. WHENEVER THE CONTACT PLACED THE VEHICLE INTO REVERSE OR DRIVE I WOULD VIOLENTLY SWITCH INTO GEAR CAUSING THE VEHICLE TO SLIGHTLY SURGE FORWARD. THE VEHICLE HAS BEEN TAKEN TO THE DEALERSHIP ON THIRTEEN DIFFERENT OCCASIONS WHERE SEVERAL DIFFERENT PARTS HAVE BEEN SERVICED ON THE TRANSMISSION;HOWEVER THE CONTACT IS STILL EXPERIENCING THE FAILURE. THE CONTACT HAS NOTICED THE FAILURE SINCE THE VEHICLE WAS PURCHASED. THE CURRENT AND FAILURE MILEAGES WERE 14000.
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 26, 2026