2015 Mercedes-Benz C 300 Owner Complaints

The contact owns a 2015 Mercedes-Benz C300. The contact stated that while driving at various speeds and depressing the brake pedal, the vehicle fishtailed on several occasions. The vehicle was taken to an independent mechanic, where it was raised on a lift, and the mechanic discovered that the rear subframe was severely corroded. The mechanic determined that the failure was associated with Manufacturer Communication Number: MC-10232321 (Structure); and referred the contact to a dealer for assistance. The vehicle was towed to the dealer, where the failure was confirmed, and it was discovered that the rear subframe had separated. The dealer informed the contact that the vehicle was unsafe to drive. The contact was provided an estimate for the repair and was informed that goodwill assistance would not be provided. The vehicle was not repaired due to the cost. The manufacturer was notified of the failure and informed the contact that the dealer was unreachable. The failure mileage was approximately 120,000.

NHTSA ID

11754977

Incident

Jul 15, 2026

Mileage

120,000 mi

The contact owns a 2015 Mercedes-Benz C300. The contact stated that while the vehicle was parked, the contact became aware that the panoramic roof failed to close as intended. The vehicle was taken to the dealer, where it was determined that the panoramic roof guide rails had failed. The contact was informed that the panoramic roof guide rails needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure, and a case was filed. The contact was informed that the mileage and age of the vehicle had exceeded the limitation. The failure mileage was approximately 110,000.

NHTSA ID

11753779

Incident

Apr 15, 2026

Mileage

110,000 mi

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.)

NHTSA ID

11753660

Incident

Jul 2, 2026

The contact owns a 2015 Mercedes C300. The contact stated that the driver's side rear brakes and rotors were rusted. The contact stated that when the brakes were applied, they were slow to respond. The TPMS warning light was illuminated. The vehicle was taken to a braking center, which declined the warranty for the aftermarket parts. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not notified. The approximate failure mileage was 176,000.

NHTSA ID

11740646

Incident

Apr 1, 2026

Mileage

176,000 mi

I was driving my car was sputtering or trying to shut off while I press the gas and I let go of the gas and it catches and stayed on. I took it to the dealership and they said they found nothing wrong. May 3rd around 12pm im driving on the freeway and as im getting on the express lane going 60 it dies and I couldn't move the steering wheel and I slammed into a guardrail. After doing research my car (vin [XXX] ) had multiple recals from the fuel pump and steering wheel and the dealership never fixed or checked any recalls before selling it to me. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11736219

Incident

May 3, 2026

The contact owns a 2015 Mercedes-Benz C300. The contact stated that while driving at an undisclosed speed, there was an abnormal sound coming from the vehicle. The vehicle was driven to the shoulder of the road. The contact inspected the exterior of the vehicle and became aware that the moon roof panel had detached, and the moon roof panel flew off the vehicle. The dealer was made aware of the failure. The contact stated that the vehicle was previously repaired under NHTSA Campaign Number: 21V197000 (Structure) in 2021. The contact was informed that the repair was not covered under warranty. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. The manufacturer was made aware of the failure but provided no assistance. The failure mileage was approximately 62,612.

NHTSA ID

11733048

Incident

Apr 17, 2026

Mileage

62,612 mi

The contact owns a 2015 Mercedes-Benz C300. While driving approximately 15 MPH, the brake pedal was depressed, and the body of the vehicle shifted to one side. The vehicle was drivable after the failure. There was no warning light illuminated. The vehicle was driven to the residence and parked. The contact stated that due to the failure, the vehicle was unsafe to drive. An independent mechanic was contacted, and it was determined that the rear subframe was corroded. The vehicle was not repaired. The manufacturer was notified of the failure, and it was confirmed that the VIN was not under recall. The failure mileage was not available.

NHTSA ID

11722220

Incident

Feb 16, 2026

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. I limited driving/use due to the risk; issue is a structural safety concern rather than cosmetic. Confirmation: Yes on multiple visits since Oct 2023 -Yes—diagnosed and documented by Mercedes-Benz of Silver Spring on Oct 2 2023, Nov 2023 and Dec 2025. Technician confirmed severe corrosion/rust perforation on the rear subframe requiring replacement. No No

NHTSA ID

11712059

Incident

Aug 22, 2025

Fuel hose system leaking. Inhalation of gas fumes caused headaches and nausea. Risk of vehicle fire. Yes, the problem has been confirmed by a Mercedes dealer. This is a known issue with Mercedes C300 2015 models and other years. There have been other complaints/lawsuits against Mercedes not wanting to pay for the issue. No warnings just strong gas smell.

NHTSA ID

11707032

Incident

Nov 2, 2025

Rear subframe rusted out, car is not safe to drive

NHTSA ID

11698179

Incident

Oct 23, 2025

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

NHTSA ID

11696650

Incident

Oct 27, 2025

I’m the owner of a Mercedes Benz C- Class Sedan 2015. My Rear Sub Frame Rusted Through at The right trailing arm - Fails state inspection. Mercedes Benz has issued a extended 20 year warranty on all vehicles from 2008 - 2015 C - Class Sedan for Rear Sub Frame that rusted out. Mercedes Benz service advisor stated that my vehicle was not under that extended warranty when he run my vehicle Vin number. My vehicle should be under that warranty, I have the same problem with the same vehicles on the list. Please help. Thank you

NHTSA ID

11695279

Incident

Oct 23, 2025

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.

NHTSA ID

11688397

Incident

Sep 4, 2025

I took my 2015 vehicle to the Mercedes dealership and learned the rear subframe is rusted and has holes on two sides. I was warned that it is a safety hazard and could lead to a lack of control and other dangerous situations. I also learned that other 2010 through 2014 Mercedes models in the same class have been recalled for this exact concern. I am disappointed and upset to learn that those concerns are known, but not addressed in this model and put customers at risk.

NHTSA ID

11687651

Incident

Sep 16, 2025

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. also we take the car to the dealer every 5 Ish months and this last service is the first we have seen of this.

NHTSA ID

11687391

Incident

Sep 10, 2025

The contact owns a 2015 Mercedes-Benz C300. The contact stated that upon taking the vehicle for the State Inspection, the contact was informed that the rear subframe was rusted, and there was a hole on each side of the rear subframe. The vehicle was taken to the dealer, where an unknown diagnosis was made, and the dealer ordered an unknown part to repair the vehicle. The vehicle was not repaired. The manufacturer was notified of the failure but denied assistance. The contact was referred to the NHTSA Hotline for assistance. The failure mileage was approximately 60,000.

NHTSA ID

11681594

Incident

Aug 19, 2025

Mileage

60,000 mi

The contact owns a 2015 Mercedes-Benz C300. The contact stated while driving 40 MPH, the vehicle unexpectedly veered to the left. There was no warning light illuminated. The contact stated that the steering wheel became inoperable, and the contact was unable to straighten the steering wheel. The brake pedal was also depressed. The contact attempted to depress the accelerator pedal however, the vehicle started to stall. The contact pulled over into a parking lot and was able to restart the vehicle. The dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 82,000.

NHTSA ID

11678756

Incident

Aug 6, 2025

Mileage

82,000 mi

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 # [XXX] , 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 was then told, it has to come from the head office in Germany. Nothing like getting a run around not what I expected from Mercedes Benz USA, INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11675408

Incident

Jan 21, 2025

Failed component: Front Sunroof Clip What component or system failed or malfunctioned, and is it available for inspection upon request? Sunroof clip, yes. How was your safety or the safety of others put at risk? The glass pane lifted while the car was in motion and had to be held down to secure it until the car stopped. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? No Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? No While merging to enter the freeway at approx 45-50 mph I opened my sunroof. At about halfway back the glass began to lift up off the track/railing as if it was going to fly off the track. Had I not been holding the button to open the sunroof I would not have noticed and the entire glass pane would have blown off, possibly damaging the car or worse flying off and hit another car. I had to hold the glass in place to keep it from flying off until I was able to exit the freeway. Once I stopped the car to inspect the sun roof I noticed the clip that secures the glass to the track was broken (crumbled) in the sunroof track. I removed the pieces of broken plastic from the track and was then able to close the sunroof. I am now unable to safely open my sunroof while the vehicle is in motion.

NHTSA ID

11672076

Incident

Jul 7, 2025

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.

NHTSA ID

11671701

Incident

Apr 2, 2025

Mileage

110,000 mi

The contact owns a 2015 Mercedes-Benz C300. The contact stated that while his wife was driving at an undisclosed speed, the roof panel detached from the vehicle and fractured. The contact stated that the roof panel had previously been replaced, but the failure occurred. The vehicle was taken to the dealer, where it was determined that the front roof panel needed to be replaced. The vehicle was not repaired. The contact related the failure to NHTSA Campaign Number: 23V854000 (Structure); however, the VIN was not included in the recall. The manufacturer was made aware of the failure. The failure mileage was approximately 70,000.

NHTSA ID

11669469

Incident

Jun 26, 2025

Mileage

70,000 mi

Check Engine light came on recently, fault code P052E is identified by scanner. Car has 60,000 miles on original it. MB dealer wants to charge $300 for diagnostics, repair job (parts and labor) may cost over $2,000. Since this is critical emission compliance part/system, why is it not recalling?

NHTSA ID

11669468

Incident

Jun 16, 2025

Panoramic glass sliding plastic brackets broke off while driving at 25-35 mph Lifting up the glass off the vehicle. Quick reaction saved the large detached glass from flying off into the roadway injuring or killing someone. Vehicle was 5 years old and out of warranty. Dealer estimated repair cost at $2500

NHTSA ID

11665351

Incident

Jun 1, 2020

On May 27th, 2025, during highway driving suddenly the sunroof got open by itself for like 3 inches upwards from the front and after exiting the highway i stopped and push the sunroof downwards by applying the force and apply duct tape all around the sunroof to keep it protect from sun and rain so i am not driving anymore before getting it resolved.

NHTSA ID

11664393

Incident

Jun 2, 2025

Rear-subframe corrosion at the lower-control-arm mounts has progressed to the point where both arms have play and produce loud metallic bangs while braking or turning at low speed. Two independent shops lifted the car, documented flaking rust around the bushing sleeves, and advised the subframe is structurally compromised and could let a control arm detach under load. The corroded subframe remains installed and can be inspected on request. Safety risk: a detached rear control arm would cause sudden, unpredictable steering and loss of control. The vehicle already pulls right under braking, and feels very unstable in curves Problem has been reproduced and photographed by two independent repair facilities. No manufacturer representative has inspected the vehicle so far. Additional component failures possibly linked to the same progressive chassis stress: premature wear of both front CV axles; timing-chain stretch with worn guides; slack oil-pump chain; upper & lower oil-pan gasket leaks; water-pump seepage; right engine-mount collapse; persistent misfire traced to a loose intake-hose clamp; transmission-cooler hose clip released under pressure, dumping all ATF and destroying the automatic transmission; excessive play in all four lower control-arm bushings. The transmission and the other components were replaced 1-2 months before the subframe bro History: A faint clank from the rear suspension first appeared roughly three years into ownership. Dealer service dismissed it as “normal noise,” and warranty would not cover “loud clanks,” so the issue went unaddressed. The noise has grown steadily into the current condition, suggesting long-term subframe corrosion that was never inspected or remediated. No collision, flood, or off-road use; the car has typical Northeast winter-salt exposure. The failure pattern matches subframe-corrosion cases already acknowledged by the manufacturer on this model, although this serial number is not yet included in the official campaign.

NHTSA ID

11663816

Incident

May 19, 2025