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 2015 Mercedes-Benz C300 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2015 Mercedes-Benz C300. The contact stated that approximately every 6-8 months, the vehicle sputtered while driving at various speeds or while idling. The contact stated that a month after the first failure had occurred, the front end of the vehicle lowered as if the shocks or hydraulic system had failed. The failure had occurred 3 times within a year and a half. The contact stated that after the second failure, the entire vehicle lowered several inches, and at the third failure, only the front end of the vehicle was lowered. The dealer diagnosed the vehicle and determined that the hydraulic pump and the connections from the shocks to the hydraulic pump had failed. The failure reoccurred approximately 8 months later. The vehicle was returned to the dealer who diagnosed the same failure and completed the same repairs. …
The contact owns a 2015 Mercedes-Benz C300. The contact stated that upon taking the vehicle to an independent mechanic for a routine maintenance check, the contact was informed that there was severe corrosion on the subframe of the vehicle. The contact was informed that the vehicle was unsafe to drive and that several failures might occur due to the failure. The contact stated that recently, while depressing the brake pedal, the vehicle swerved, and the contact lost control of the vehicle. Upon investigation, the contact discovered that there was a warranty on the vehicle related to the failure. The manufacturer was notified of the failure, and the contact was informed that the vehicle was no longer covered under the warranty. The vehicle was not repaired. The failure mileage was approximately 110,000.
Failed/Malfunctioned Component: Rear subframe (structural/chassis component) exhibited advanced corrosion (perforation/rust-through), compromising structural integrity and alignment/handling. Availability for Inspection: Yes. The vehicle and the subframe are available for inspection upon request. I can provide photos, videos, and repair estimates if needed. The corroded subframe is fracture and detach suspension mounting points, which may lead to: Sudden loss of vehicle stability or control (especially during braking, cornering, or over bumps). Unpredictable alignment changes causing pulling, vibration, or abnormal tire wear that can escalate into a loss-of-control event. Increased stopping distance and potential for wheel misalignment or collapse, raising the risk of a crash involving occupants and other road users. …
On January 21,2025, I had an appointment for an inspection at Mercedes Benz of Smithtown, the dealership I use. I was informed that my car required replacement of a rotted rear subframe. A hole had rotted through, causing the car to "Fail inspection and was NOT SAFE" to drive. I was provided a video showing the damage. There was a recall in effect however, my Vin # was not included and it's status has not changed. The 2015 C-Class Sedan/Coupe Vin # [redacted] , which was neglected to be included in the recall covers 2008-2015 C-Class Sedan/Coupes, regarding rotted rear subframe. MBUSA extended the vehicle Warranty 4 yrs/ 50,000 miles to 20 yrs/unlimited miles. However, I do not qualify for reimbursement of $4,014.92, because my Vin # was left off the list. Mercedes customer assistant center states they can't help, has to be included by NHTSA, when I said they cannot add a Vin #. …
I have a 2015 Mercedes-Benz C300 4Matic got a letter from the company car had few recalls to address. Dropped the at Mercedes-Benz Hampton VA dealership on 12/06/2023 at 8:30 AM EST. After few hours got a call from the dealership that rear subframe of the has bad corrosion and because of the rust it got holes in it which is a bad safety risk. Risk is so great that it cant pass Virginia state inspection. I did a good online research and found it is a common issue in Mercedes-Benz vehicles and the company issued safety recall on some years and models but not on all the affected vehicles. Like my car has the exact same safety issue rear subframe got rust from inside so it was hard to notice till it became unsafe to drive the car. The dealer is asking almost $5000.00 to replace it. …
there is a recall for 2008-2015 Mercades Benz c-300 c/w204. this recall talks about the rear subframe rusting out early on this car. we have a 2015 c300 c/w205. this car is seeing the same early rust seen in the other c-300. the dealership is refusing to do right by the warranty because it is a c/w205 even thought this is a known problem for this year and type of car. I am making this because it should be extended to all c300 2008-2015 cause they all use the same subframe. they changed the subframes and the look of the c-300 starting in 2016. it also would appear that the rust is coming from the inside of the subframe making we wonder how bad it is on the inside if it is making its way to the outside of it. I believe water penetrates into the rear subframe has no drainage and begins to rust. …
My car (vin [redacted] ) a 2015 Mercedes C300 is experiencing the same premature rusting on the subframe. I was told that while a lot of Mercedes are covered, mine is not for some reason but I'm at the same risk for the subframe getting holes in it and wheels breaking off. I only have 78,000 miles on my car, only have it serviced at the dealer and it has been garaged parked. This type of damage is not typical for a car that has been this well cared for and for the amount it has been driven. I called Mercedes to honor the $5600 or to extend the warranty should it have to be replaced and they said to file a claim here.
Rear subframe completely rusted out. While driving on the hwy I heard a loud noise, a couple minutes later I hit the brakes to slow down to get off my exit and after pressing the brakes the car instantly fishtailed sending me sideways across 2 lanes of traffic. Luckily no one was injured or killed. I've seen that the car manufacturer was replacing this issue on models 2008-2015. My vehicle is a 2015 and they are telling me my vehicle is not covered for the issue. The car is not drivable and Mercedes needs to be held accountable. A critical component such as rear subframe completely rusting out in just under 10 years is unheard of and I can't afford to pay 10k to fix it. Please help
The Rear Subframe on this vehicle is rusted and has hole in it. The sub frame requires replacement. The sub frame was inspected by the Mercedes-Benz Dealership, Euro Motorcars in Germantown, MD and they recommended that the sub frame should be replaced. There is an extended warranty that has been issued by Mercedes-Benz for the Model Year and Model (2008-2015 C-Class Sedan/Coupe). However, Mercedes-Benz decline to cover the cost of the repair stating that my VIN is not part of that Warranty. This is a well documented safety issue and I believe that Mercedes-Benz should include my VIN in that extended warranty and replaced the subframe on my car.
Rear subframe rust has deemed the car unsafe to drive. Hitting a pot hole at high speed or any sudden stop could cause the subframe to collapse causing loss of control of car. Car is available for inspection upon request. Car was taken in for regular oil change and multi-point inspection when rust was noticed by mechanic at the dealership. Car is located in East TN not the snow belt. There have been recalls on similar models for the year prior, but this vin is not part of the recall and has same issue, although the number 204 which is part of the recall is stamped on the part. (Pic attached below.)
Suspension complaints in other C300 years
Frequently asked questions
How common are suspension problems on the 2015 Mercedes-Benz C300?
NHTSA has 22 complaints about the suspension of the 2015 Mercedes-Benz C300, 6% of the model year's 381 complaints. The component named most often is subframe/mounting bracket (1 mentions).
Is there a recall for 2015 Mercedes-Benz C300 suspension problems?
No. NHTSA lists no suspension recall for the 2015 Mercedes-Benz C300, though it has 11 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 2015 Mercedes-Benz C300 suspension problems start?
Half of the complaints with a recorded mileage happened before about 50,000 miles, and 40% before 25,000 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.