Which parts fail
Components named in complaints (struts, shocks, control arms, ball joints, springs).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2009 Mercedes-Benz C300 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2009 Mercedes-Benz C300. The contact stated while driving approximately 60-70 mph, the vehicle started shuddering and lost stability. There were no warning lights illuminated. The contact stated that as she disengaged the accelerator pedal, the vehicle stopped shuddering. The vehicle was taken to an independent mechanic who diagnosed that the rear subframe was rusted and had fractured into two pieces on both sides of the vehicle, and the lower control arms were hitting the gas tank. The check engine warning light and TPMS warning light were illuminated at the time of the diagnosis. The manufacturer was not made aware of the failure. The vehicle was not repaired. The approximate failure mileage was 120,000.
The contact owns a 2009 Mercedes-Benz C300. The contact stated while driving 70 MPH, he heard an abnormal clunking sound coming from the rear of the vehicle. The contact veered to the side of the road. After looking under the vehicle, the contact noticed that the subframe located next to the gas tank was fractured. The vehicle was taken to an independent mechanic where it was diagnosed that the rear subframe had fractured from the weld point. However, the parts to do the repair were not available. The vehicle was not repaired. The dealer was not notified of the failure. The manufacturer was notified of the failure and referred the contact to the dealer. The failure mileage was approximately 190,000.
The contact's son owns a 2009 Mercedes-Benz C300. The contact stated upon taking the vehicle to the dealer for servicing, he was informed that the subframe was severely rusted. The contact stated that his son then informed him that while he was driving approximately 50 MPH and depressing the brake pedal to come to a complete stop, the vehicle started wobbling significantly. The dealer replaced the subframe, the rear tires, and completed an alignment on the vehicle. The vehicle was repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA. The failure mileage was approximately 87,000. Vehicle has been repaired.
The contact owns a 2009 Mercedes-Benz C300. The contact stated that while her husband was driving at an undisclosed speed, the vehicle swayed on the roadway. The vehicle was taken to an independent mechanic who diagnosed that the rear subframe was corroded and needed to be replaced. The mechanic contacted the dealer to order the replacement part and was informed by the dealer that there was a recall for the subframe; however, the VIN was not included. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 70,000.
The contact owns a 2009 Mercedes-Benz C300. The contact stated while driving at various speeds, the driver's side rear tire inverted into the wheel well due to excessive corrosion. The contact had taken the vehicle to an independent mechanic where he confirmed the failure and informed him that the subframe needed to be replaced. The manufacturer had yet to be notified of the failure. The vehicle had yet to be repaired. The failure mileage was 130,000.
the rear subframe @lower control arms right side rust on bracket when put break on the car go to right and make noise!!! the car just have 83.000 miles!! this have re call or not?we d'ont know untill seaching on web side findown couple owner C300 have problem said some
I am 80 years old, and disabled. Gave this car to my son, (age 53). Within a month, he experienced a potential LIFE THREATENING incident with the car. While driving, the car became very unstable and steering was almost impossible. The car was towed to A-1 Auto Repair in Pitman, New Jersey for analysis. This establishment has an excellent reputation for Mercedes-Benz repairs. Upon extensive review the shop advised "customer vehicle is very unsafe to operate and should not be driven"The Invoice states " ...During road test vehicle is unstable and steering and braking are out of specification and feels very unstable to operate. Checked vehicle suspension and undercarriage to diagnose rear subframe rusted off body mounts. and is hanging off left rear of body and subframe. …
I bought this car for my 18 year old son based on Mercedes reputation for safety and longevity, only to discover that Mercedes has a widely acknowledged issue with rotted sub-frames -- it's a serious safety issue and recalled in other countries. My son was was driving on the highway and the tire exploded. He was so close to being killed because the car went out of control. After getting it towed to my mechanic, he advised me that alignment adjusters were stuck, the subframe was rotted, the lower control arm subframe mounts were broken from the subframe and they were hitting the gas tank. Luckily, the tire only exploded as oppose to the entire vehicle bursting in flames. There were no warning lights or messages, only the feeling that the tires needed to be aligned. We bought new tires and were told an alignment was done from Town Fair Tires, which was untrue. …
Suspension Cross-Member - Mercedes-Benz (204-350-01-41) Driving regularly suddenly fill like the rear passenger side tire moved unevenly, then went to the tire shop, and when they take out the tire see how the rear frame was rusted and broken in a straight line exactly in the middle of the tire hole area. Then start to check used cars to donate that part and All of them have the same trouble in that piece, so I decided to review the frame and discover that the rust begins to damage the opposite side too, so I'm pretty sure is a component failure in metal and materials more than simple rust.
Brought in vehicle for problem when braking, car would pull to one side. Repair shop said rear sub assembly was rusted and they were aware of others like my vehicle with the same problem. Looked up some Mercedes Benz forums online and discovered many of the same problems with the C300 model (2008 and newer) my vehicle is a 2009 Mercedes C300 4Matic. I do live in Minnesota
Suspension complaints in other C300 years
Frequently asked questions
How common are suspension problems on the 2009 Mercedes-Benz C300?
NHTSA has 36 complaints about the suspension of the 2009 Mercedes-Benz C300, 6% of the model year's 576 complaints. The component named most often is subframe/mounting bracket (2 mentions).
Is there a recall for 2009 Mercedes-Benz C300 suspension problems?
No. NHTSA lists no suspension recall for the 2009 Mercedes-Benz C300, though it has 8 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2009 Mercedes-Benz C300 suspension problems start?
Half of the complaints with a recorded mileage happened before about 92,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.