Mercedes-Benz C-Class Complaints

3,817 consumer complaints on file.

#11766013September 21, 2026
ENGINE, POWER TRAIN
The M264 2.0L engine suffered a catastrophic internal failure. While making a left turn at an intersection, the vehicle suddenly shut off and stalled, leaving the car stranded in active traffic and creating an immediate safety risk. Prior to the shutdown, the check engine light came on accompanied by severe shaking and misfires. The vehicle was inspected by an authorized dealership service center, which confirmed complete engine failure. Mercedes-Benz issued a 15-year/150,000-mile extended warranty for the M264 exhaust valve and cylinder head assembly, but warranty coverage was refused because the cylinder defect progressed to total engine destruction. The vehicle remains available for inspection upon request.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11765519September 19, 2026
AIR BAGS
Airbags didn’t deploy during accident, vehicle hit on drivers side, greatly impacted, driver seatbelt was on. All recalls were completed. Impact from other vehicle that hit my vehicle had deployed airbags.
Crash:
Yes
Fire:
No
Injuries:
1
Deaths:
0
#11765556September 19, 2026
FUEL/PROPULSION SYSTEM
Noticed a strong odor of gas, well actually my kid did was sitting in backseat. I had just filled up and the smell didn't disipate. The next morning i still smelled it. I removed the seat and cover on the drivers side and almost half a gallon of pure gas was sitting there. I cleaned everything up removed all the gas. Reconnected the battery and its litteraly coming from micro cracks in the lid. I can send you the lid. I have since replaced it now i'm dealing with a 3699 code and just don't understand why a part like this that is recalled on other models with my 2013 w204 c class was not included just e, and cls.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11765376September 18, 2026
SUSPENSION, STRUCTURE:BODY
I noticed some unstable braking at higher speeds. I took the vehicle to a mechanic and he discovered severe rust with perforation of the rear subframe "very near to where some of the suspension connects to it and is allowing a lot of extra movement, especially under braking." He told me that the vehicle was unsafe to drive on the highway or at speeds over 40 mph and should be repaired, preferably through Mercedes as soon as possible. I've reached out to Mercedes Benz USA. They told me that this has been a common problem and some vehicles have had the warranty extended because of it. My vehicle is not included in the warranty extention but they suggested that it may be eligible for a "goodwill" repair. I've reach out to my local Mercedes dealership to further investigate the problem and are awaiting a return call.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11764699September 16, 2026
STRUCTURE:BODY
Front roof panel came detached at hwy speed
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11764481September 15, 2026
ENGINE, POWER TRAIN, ELECTRICAL SYSTEM
The vehicle experienced a severe safety issue involving a sudden loss of motive power in active traffic. 1. Initial Symptoms & Diagnosis: Recently, the Check Engine Light illuminated. Although the light turned off before my scheduled appointment, I still brought the vehicle to an authorized Mercedes-Benz dealership for a safety inspection. 2. Dealer Confirmation: The dealership inspected the vehicle and diagnosed an internal electrical fault with the engine oil control valve and harness. They recommended replacing the parts. Because the vehicle seemed to be running fine and the dealer did not warn me that it was unsafe to drive, I drove the vehicle home to consider the repair. 3. Critical Safety Incident: Shortly after bringing the car home, I was stopped at an intersection. When I attempted to accelerate, the vehicle suddenly entered "limp mode." It lost almost all motive power and would only crawl forward at a very low speed. This sudden loss of acceleration in the middle of traffic put me at an immediate risk of a collision. I had to pull over to the side of the road and restart the engine to regain normal function. 4. Prior Symptom: Looking back, I experienced a similar brief loss of power approximately one year ago. However, the vehicle recovered quickly after I restarted the engine, and no warning lights came on, so I was unaware of the severity of the defect at the time. The vehicle has less than 20,000 miles. An internal engine valve failure causing a sudden loss of acceleration on public roads is a major safety defect. The vehicle is currently parked for safety reasons and is available for inspection upon request.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11764483September 15, 2026
SUSPENSION, POWER TRAIN
The rear structural subframe on my vehicle has experienced severe, premature corrosion perforation (rotting from the inside out), resulting in a major compromise of the vehicle’s structural integrity. This subframe is a critical safety component that supports the entire rear suspension, differential, and braking components. The subframe has rusted to the point of developing holes and structural cracks under normal operating conditions. This severe deterioration creates an immediate safety hazard, as a total failure or snapping of the subframe while driving can cause a sudden loss of vehicle control, unpredictable suspension geometry changes, and a severe risk of a high-speed crash.Mercedes-Benz has previously acknowledged an identical, widespread manufacturing defect and issued an extended 20-year warranty (NHTSA ID NCU-2023020004) for older model lines (such as the W204 and W212). However, my specific vehicle is currently excluded from that extension, despite suffering from the exact same premature metallurgical failure and safety risk. The deterioration is identical to the covered models, where road debris and water get trapped inside the hollow subframe unit, causing it to oxidize and disintegrate undetected from the interior until structural failure occurs.This constitutes a severe safety hazard. Driving with a compromised rear subframe risks a catastrophic detachment of the rear axle, control arms, and braking lines while at highway speeds. A sudden failure will lead to immediate loss of steering control and an incredibly high probability of a severe motor vehicle accident, endangering lives. I am filing this complaint to urge the NHTSA to investigate Mercedes-Benz and mandate an extension of the existing warranty framework to cover newer model years that exhibit the exact same premature corrosion failure. Dealers are denying coverage based on arbitrary VIN cutoffs, forcing owners to drive unsafe vehicles or pay out of pocket for a known structural defect.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11764059September 14, 2026
UNKNOWN OR OTHER
Vehicle has prematurely rusted subframe. It is a know manufacturer defect, for which the manufacturer is covering repair cost for owners of the preceding model, but refuses to acknowledge responsibility on this model. (W204 model covered — W205 Mercedes (only offered $500.00 on a repair they value at over $6,000.00.))
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11763782September 12, 2026
FUEL/PROPULSION SYSTEM
Fuel tank is rusting. Leaking fuel, heavy fuel smell inside cabin. My saftey and anyone around the vehicle would be at risk due to fire chance. Confirmed by independent service center Vehcile has only been inspected by me and the shop Only symptom that appeared was fuel smell in my garage and a puddle of gasoline underneath the vehicle.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11761726September 2, 2026
UNKNOWN OR OTHER
I am reporting a potential safety defect involving the locking/key-detection system in my 2015 Mercedes-Benz C300. On [XXX], at approximately [XXX] p.m. in Coral Ridge, Fort Lauderdale, I secured my young son in his car seat. My purse, containing the key fob, and my phone were on the front passenger seat. I closed the door and walked around to the driver's side. The vehicle had locked all doors by itself. I did not press the lock button or intentionally lock the vehicle. There were no warning lights, messages, alerts, or other symptoms beforehand. My [XXX] son was trapped inside the locked vehicle, and both my key and phone were also inside, leaving me unable to access him or call for help. I flagged down a passing car, and we ultimately had to break a window to reach him. The vehicle has not been inspected by Mercedes-Benz, a dealer, police, insurance, or an independent service center, and the issue has not been reproduced or confirmed. After replacing the window, I have not attempted to recreate the incident because of the safety risk. The vehicle remains available for inspection upon request. I am concerned that the vehicle can lock with the key fob inside the passenger side, creating a potentially serious risk if a child or vulnerable occupant is trapped inside, particularly in hot weather or where immediate assistance is unavailable. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11761340September 1, 2026
STRUCTURE
The contact owns a 2015 Mercedes-Benz C300. While the contact’s son was driving approximately 20 MPH, the vehicle veered to the left and into the next lane when the brake pedal was depressed. The vehicle was cautiously driven back to the residence and parked. The vehicle was later towed to the local dealer to be diagnosed, and it was determined that the rear subframe had severe rust and was fractured and needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure, but no assistance was provided. The contact was informed that the vehicle was not covered under the manufacturer’s extended warranty coverage for the failure. The failure mileage was 110,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11761115August 31, 2026
SERVICE BRAKES
Brake line corrosion issues, related and reported along with the sub-frame assembly corrosion. After getting the sub-frame repaired XXX, corrosion and deformation of the tie rods and control arms caused vibration and noise at speed, and while cornering. Repaired XXX and vehicle inspection discovered no leaks in the corroded brake lines. After this repair, brake fluid warning light appeared. Very costly repair done at the MB dealership, in [XXX]. This is a common defective issue associated with the corrosion of the subframe, and should be attached to the subframe campaign, and reimbursed by the MFG. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760695August 30, 2026
ELECTRICAL SYSTEM, ENGINE, POWER TRAIN
CEL followed by no crank / no start. Codes u3017 and u0168. Software flashed and no crank / no start returned. SAM & EIS modules replaced and no crank/no start returned with new codes. U103F00 + P143400 + P051300. Now Mercedes is directing the replacement of the ethernet harness between the SAM and EIS. This intermittent communication or electrical fault can cause the vehicle to unexpectedly lose the ability to start. This creates a safety concern because the vehicle could fail to restart after being stopped in traffic, at an intersection, at a fuel station, or in another location where reliable starting is necessary. The intermittent nature of the failure also makes it difficult to predict when it will occur. The vehicle has sometimes operated normally for extended periods and then unexpectedly failed to start. As of filing this report the issue remains unresolved.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11760266August 28, 2026
SUSPENSION
I am a mechanic speaking on the behalf of a customer; this customer is experiencing problems with her rear subframe. The older generation of her car has a famous issue with rear subframe rusting out. Her car uses an updated part number that is almost identical in construction to the failure prone part that was famous for rusting out, although they are NOT the same number. The failure prone number is 2123503805 or 2043500141, they are installed on the older chassis, w204, w212, etc. The part that is in THIS vehicle is 2123503605, the construction is almost identical to the part numbers listed for the w212 and w204 provided above. There is no drainage holes provided for water that has entered through rain or any other detritus that will permeate on the road's surfaces through natural progression of the vehicle's life, like on the older chassis. The material used is steel with paint on the outside instead of some sort of encapsulation that coats both inside and outside surfaces. And because these don't have any sort of ability to evacuate any substances, they are interacting with unprotected metal and will react into rust. This failure can lead to misalignment at the very minimum of problems, at the worst, it can cause control arms falling off, causing wheel hub assemblies to fall off, this shouldn't have to be explained but this can cause major injury or death, not only to the passengers to the vehicle, but to others who share the misfortune of being at the wrong place at the wrong time. And, the understanding of these not being the SAME part shouldn't warrant the extension of the recall to these particular vehicles, but the failures are similar to what was seen before on other older vehicles and should warrant further investigation. With hope, this could just be an isolated incident, but since patterns are uncanny, this should be investigated with some interest to the public wellbeing. Cordially Naseam F. Samaan Licensed Virginia State Inspector. Sanko Auto Care
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11759626August 26, 2026
STRUCTURE
The contact owns a 2018 Mercedes-Benz C-300. The contact stated that while driving 70 MPH South on the interstate towards Miami, the front panel detached without warning. The contact pulled over to inspect the vehicle and became aware that the panel between the windshield and sunroof had detached. The contact stated that water started entering the vehicle from several areas. The sunroof was inoperable. The contact called the insurance company. The contact associated the failure with NHTSA Campaign Number: 23V854000 (Structure). The local dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted, but no additional assistance was provided. The approximate failure mileage was 83,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11759811August 26, 2026
ELECTRICAL SYSTEM, VEHICLE SPEED CONTROL, EXTERIOR LIGHTING
I acquired a Mercedes-Benz C300 from Mercedes-Benz of White Plains at [XXX] [XXX] on the last day of XXX Within 2 days of the car sitting in my driveway, I took it out for a drive; the electronic systems failed while I was driving on the highway. The speedometer and odometer went dark, and the turn signals stopped working. Blind Spot Warning, All electronics. I immediately return the vehicle to the dealership. One of the technicians and the manager acknowledged that not only do they see it because it’s still current, but they’ve had similar issues before. They would attempt to repair it with some software updates. In that same conversation, they acknowledged again that this problem had happened before in different capacities. The dealership still has the car 23 days later. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11759861August 26, 2026
UNKNOWN OR OTHER
The convertible roof gets stuck partially in open or closed position. It has to be forced closed. The vehicle is always garaged and the convertible was used very carefully but still has been troublesome from the beginning
Crash:
No
Fire:
No
Injuries:
1
Deaths:
0
#11759222August 24, 2026
UNKNOWN OR OTHER
Vehicle rear subframe has rusted through, causing vehicle to swerve upon braking, making the car unsafe to drive for the occupant, other vehicles on the road, and pedestrians. Mercedes dealer has advised that subframe has rusted through, requires replacement. The car will be brought to the dealer for repair (at owner's expense) by Friday, 8/28/2026. We can request that the dealer provide us with the subframe - please advise. The vehicle provided no warning indications.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11759255August 24, 2026
SUSPENSION
The rear sub frame has rusted and part of it has failed
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11757917August 19, 2026
SUSPENSION
An inspection of my vehicle on August 6, 2026 disclosed that the rear subframe has corrosion, including perforation. It is my understanding that this problem has been identified in mine and many other Mercedes-Benz models, and that Mercedes-Benz has offered an extended warranty to replace the subframe in certain of these models, but my model for the year it was manufactured was not included. I was not made aware of this potential problem by Mercedes-Benz, and they are not offering an extended warranty to resolve this serious safety issue.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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