2015 Mercedes-Benz C-Class Complaint Log

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.

The R&R rear subframe is showing premature corrosion that can cause structural failure. This can lead to rear suspension detachment, erratic driving behavior, and severe safety risks. This problem has been confirmed by the Mercedes Benz dealer. This has been inspected by the Mercedes Benz dealership. There were no warning lamps, messages or other symptoms of the problem prior me finding out it was failing. I had a multi inspection performed on my car due to another issues and the MB service dept found it during that time. Which means if I had never had the multi inspection done due to another issue I was having with the car, I would not have known.

Rear subframe has rust and holes. Dealer is saying not covered under warranty and asking for 8000

REAR SUBFRAME RUSTED OUT AND BROKEN

The rear subframe completely rusted out on both sides causing the car to swerve very dangerously to the left when braking. The subframe was diagnosed by the dealer. There was a " collision prevention assist inoperative" warning a week prior the the car noticeably swerving when braking

Fuel pressure pump hose on top of the engine leaks gasoline this is a serious safety concern the hot engine can catch fire easily, I noticed due intoxicating vapors in cabin while driving because car takes air from q side of the engine to the cabin. The car only has 28k miles on it.

Exhaust camshaft pulse wheel shifted on camshaft. Replacement of camshaft, positioner, oil control valve, timing chain and chain tension was recommended.

After strong fuel odor in interior of car, inspected the engine and discovered fuel in the top of the engine this is a serious safety concern due possible car fire. The leak appear to be due failure of a top engine gasoline hose due low quality. The car barely has 30k miles .

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.

When buying this car from Auto Shoppers, they was an airbag light on but dealership said it was a sensor from auto detail on car or recall. Got diagnostic from Mercedes Benz, findings was there was no air bag in place on drivers side. Dealership did not tell us there was no air bag and only was a sensory/recall and are refusing to fix it.

I am reporting a structural failure of the rear subframe due to corrosion on my 2015 Mercedes-Benz C300 4MATIC. The failure was diagnosed by an authorized Mercedes-Benz dealer, who confirmed that the rear subframe has corroded and broken, compromising the structural integrity of the vehicle. This is not cosmetic rust. The subframe is a load-bearing structural component, and its failure creates a serious safety risk, including potential loss of vehicle control. I have been advised that the vehicle may be unsafe to operate in its current condition. The vehicle has approximately 143,000 miles and has been registered and operated in Connecticut, a salt-use state. However, this level of corrosion leading to structural failure of a major suspension component is premature and not consistent with normal wear and tear, even in such environments. I contacted Mercedes-Benz USA and escalated the matter to an Executive Referral Manager. Mercedes-Benz acknowledged the seriousness of the issue but declined to provide any repair assistance, stating that my vehicle falls outside of warranty extension and goodwill parameters. Mercedes-Benz did not dispute the nature of the failure or its safety implications, but refused to address the issue based solely on internal policy criteria such as age and mileage. A rear subframe supports critical suspension components. Corrosion leading to structural breakage can result in instability, misalignment, or failure of suspension components while driving, increasing the risk of a crash. This issue appears to be consistent with known reports of rear subframe corrosion in similar Mercedes-Benz vehicles, raising concern about a broader safety defect. The failure was identified during inspection, and repair costs are estimated at approximately 5,000–6,000. I am submitting this complaint due to the safety risk posed by structural failure and the manufacturer’s refusal to address the issue.

Strong gas odor coming from vent when heat and AC is on. Odor was causing dizziness and had to drive with window open or vent off. When opening the hood gas odor was also present. Brought to the mechanic and found fuel lines leaking. Went online and found out this is a very coming problem. I had to spend $657. to repair. Mechanic stated Mercedes issued a service bulletin but not a recall.

1. What component or system failed or malfunctioned? The low-pressure fuel feed line (Part No. 274-070-35-00) and its associated clamps connected to the high-pressure fuel pump. Availability: State: The defective hose is currently on the vehicle and is available for inspection. If the repair proceeds, I request the dealership to retain the failed part for my inspection. 2. How was your safety or the safety of others put at risk? The failure resulted in raw fuel leaking directly into the engine compartment. This creates an immediate and severe fire hazard, as gasoline is being released near high-temperature engine components. Furthermore, the strong odor of gasoline entered the cabin through the HVAC vents, exposing passengers to toxic fuel vapors while the vehicle was in operation. 3. Has the problem been reproduced or confirmed? Yes. The defect was confirmed by Mercedes-Benz of Orange Park (Dealer Code: 64111). The technician performed a 'cold start' inspection and verified fuel leaking from the low-pressure line to the high-pressure pump. > Note: My service advisor's admitted: Yes sir we will do the hose. 4. Has it been inspected by the manufacturer, police, insurance, or others? Answer: The vehicle has been inspected and the failure documented by an authorized Mercedes-Benz dealership technician. It has not yet been inspected by insurance or police as no fire has occurred yet; however, the dealership has identified the part as defective. 5. Were there any warning lamps or other symptoms prior to failure? There were no warning lamps or dashboard messages. The primary symptom was a pungent smell of raw gasoline inside and outside the vehicle, specifically during cold starts. These symptoms first appeared recently [January 3rd, 2026] and became persistent as ambient temperatures dropped.

I took my car for service and they found a rusted rear subframe, with a small hole in it. I was informed that the car was not safe for my annual trip from NJ to FL (about 1000 miles). I was also told that this defect was a recall for cars through 2014. My car is a 2015 and I have the same defective part - which is supposed to be manufactured with rustproof material. I am requesting that this car be recalled and the part replaced by the manufacturer.

I have been informed by my dealer's service unit that the rear subframe of my car (2015 Mercedes C class) is rusted with holes. My understanding is that this can affect the integrity of the structure and cause problems while driving. According to your website [XXX] ) , this should be covered under a warranty extension. However, Mercedes says that my car is not, and to fill out this form if I believe it should be. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Purchased this car in September 2024 for our [XXX] son. Upon inspection at our local Mercedes Dealership on December 1, 2025, we were informed that the rear subframe should be immediately replaced as there is a rusted hole in the subframe, "compromising the structural integrity of the rear of the vehicle." We were informed that the prior bulletin issued for 2010-2014 C-Class models did not include our 2015 C-Class. We were quoted over $5200 to repair the subframe. There were no warning messages, lights problems that were noted, prior to inspection. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My wife first noticed loud noise from the back of the car when braking. Subsequently, when I drove it one day after, the car lost balance and nearly went into the opposite direction of the road on a two-lane street. The MB dealership later confirmed the problem was a severely corroded rear subframe that needs to be repaired at very significant expense. This is a serious safety issue that could have caused a head-on collision for me and my wife as a passenger on that occasion. I believe this issue warrants a full investigation by the NHTSA. I understand other Mercedes models such as the 2008-2015 C300 (W204) had the same corrosion issue and was under a recall but my car model (W205) was not covered by this recall. Thank you for your attention to this matter. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My car’s rear subframe was so badly disintegrated due to severe corrosion. It made the driving so dangerous when braking and nearly caused an head-on collision. I have reported this issue under tracking number 11701609 and would like to provide pictures on the corrosion issue.

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.

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

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

Rear subframe rusted out, car is not safe to drive

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.

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.

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.

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

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.

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.

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.

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.

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?

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.

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.

The contact owns a 2015 Mercedes-Benz C300. The contact stated that while driving at an undisclosed speed, there was an abnormal clunking sound coming from the front suspension of the vehicle. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the steering rack locknuts, observing that the steering rack had become loosened. The vehicle was not repaired. The vehicle was then towed to the dealer, who confirmed the diagnostic result. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 18V850000 (Steering), but the VIN was not included. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA hotline for assistance. The failure mileage was 70,000.

Power steering malfunction Car unable to drive I believe there is supposed to be a recall for this issue but not popping up when I put in VIN number Warning lamps come up. Sometimes every light on dashboard. Took it to Mercedes but it was when code was not popping up and they said I needed a new battery. Did that but still an issue. Has also happened when driving. Sometimes collision assist plus light comes on and power steering acts up. Light I am pointing at in picture is another light that consistently pops up I have been able to intermittently fix problem by resetting computer by unplugging battery for 15min or longer. As well as confirming full service on vehicle. Now it isn’t working though.

Rear subframe broke while driving- made stearing/controlling/breaking car very difficult & dangerous.... After reviewing on internet- MB is aware of this problem

Structure,Body.Roof & Pillars

Engine Light- Crankcase Ventilation Valve Replacement P052E71. Vehicle will jolt aggressively at the time of acceleration.

Have noticed a lot of air noise coming from the panoramic sunroof of my vehicle when driving, and now have issues of it opening or closing properly. I researched and found a recall regarding the issues my vehicle is having, and brought it into a dealership for diagnosis. Was told my vehicle VIN was not included in the recall. This is a dangerous issue that needs to be remedied. If the sunroof malfunctions I’m afraid it will come loose from the vehicle as it is doing the same things that the recalled VIN vehicles had issue with. Mercedes needs to update and add additional VINs to this recall. I did not repair, as I was told the entire thing will need to be replaced.

The contact owns a 2015 Mercedes-Benz C300. The contact stated that while driving at 50 MPH and attempting to decelerate, the front end of the vehicle began to drift to the right while the rear drifted to the left. The vehicle returned to normal functionality, but the failure became a regular occurrence. No warning lights were illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the rear subframe. The vehicle was not repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was 136,000.

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.

I took the car for annual maintenance to Mercedes-Benz dealership. After routine check up they came back to report rusty rear subframe and told me that needs to be replaced. However this part is really expensive and models from 2008 to 2015 C300 had the same issue(premature rust) and they all received extended warranty from Mercedes-Benz for free replacement. I wanted to report this safety issue for C300 model including mine that is not covered under extended warranty.

I took my vehicle to an independent repair shop for routine maintenance and while there I was advised that the vehicle is suffering from the subframe corrosion issue. I called the manufacturer service center and they took my VIN and said I was not covered under the bulletin. The independent contractor gave me an estimate to get it repaired, however Mercedes doesn’t even have the parts needed in stock as they are backed ordered nation wide. This is our only car and it now I am forced to drive an unsafe vehicle.

The contact owns a 2015 Mercedes-Benz C300. The contact stated that while driving at approximately 70 MPH, there was a loud clicking sound coming from the panoramic sunroof. The contact stated that the sunroof then became inoperable. The contact became aware of NHTSA Campaign Numbers: 23V854000 (Structure) and 21V197000 (Structure). The dealer was contacted and confirmed that the VIN was not included in the recalls. The vehicle was not diagnosed or repaired. The manufacturer was informed of the failure and confirmed the VIN was not under recall. The manufacturer referred the contact to the NHTSA Hotline to report the failure. The failure mileage was 115,000.

Panoramic roof explode sound like a gunshot but the roof exploded

The contact owns a 2015 Mercedes Benz C400. The contact stated that while vehicle was inside a high-pressure car wash, water leaked from the roof panel at the front of the vehicle, nearby the front windshield. The cause of the failure was not yet determined, and the vehicle was not repaired. The manufacturer was notified of the failure, but no assistance was offered. The contact was informed that the VIN was not included in the NHTSA Campaign Number: 23V854000 (STRUCTURE). The contact stated that the vehicle had experienced the failure listed in the recall. The local dealer was not contacted. The failure mileage was 100,000.

The engine lamp turned yellow. The car got inspected by a mechanic and showed code. P052E, which indicates the defect in the crankcase ventilation valve. I see that many cars of the same model in which were produced about the same year had the same defect. I called the manufacture customer service and they claim that my van was not included in the recall. My vehicle likely had the same problem as other people did in the past, but for some reason my vin was not included.

failed piston wrist pins from early production of mercedes w205 c300. The issue was diagnosed by mercedes of manhattan and could not provide me a fix. Stated that the issue is common with the vehicle and it does not warrant a recall for this issue. i believe its a safety issue and my vehicle only has 60K miles

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)

Crank case ventilation Valve needs replaced. This is a hazard and multiple Mercedes owners have reported the same issues.