What 584 owners told NHTSA about the 2012 Mercedes-benz C-class Coupe

Brake line corrosion

NHTSA ODI 11604605

My 2012 c300 has a rotted rear subframe making the car not able to be driven. It has major ,life threatening, costly damage and this issue already has a recall all over the world but not in the United States. If I can get the assistance to pay this repair, it will be gladly appreciated.

NHTSA ODI 11602805

During hard acceleration the high-pressure fuel pump fails. I've never had to replace this part on any other car that I have owned. When I research the part for this car, I reviewed many forums and articles complaining about the failure of the high-pressure fuel pump on the Mercedes c250 sport or similar chassis. The vehicle performs normally until there is hard acceleration; then the engine light comes on. This causes the car to lose acceleration power and slows the car down significant and can be dangerous especially if driving on a freeway or highway. The failure of the part has been reported to occur as early as 30k miles.

NHTSA ODI 11600868

We are having issues when braking. The backend of the car wiggles when braking hard. Shop advised that the subframe on the passenger side completely broke away and on the driver side it is very rotted. They advised this is a safety issue since the broken side could pierce the gas tank. I googled this and found that there was a warranty extension for the same year and make car (document MC-10233796-0001) Spoke to the service department and they advised this did not apply to our VIN. I called the corporate number on the warranty extension letter and they advised the same. My complaint is that several other Mercedes models and makes have this issues and are covered. Why isn't ours? Based on images I found online it looks to be the exact failure mode. My son was supposed to drive the car 4.5 hours on the 4th and could have gotten into an accident or been stranded. I also read that in Germany they are fixing all vehicles with this issue.

NHTSA ODI 11600131

The contact owns a 2012 Mercedes-Benz C300. The contact stated that while the vehicle was parked, the passenger’s side rear taillight was inoperable. The vehicle was taken to a local dealer but was not diagnosed or repaired since the VIN nor the model year was not included in NHTSA Campaign Number: 14V177000 (Exterior Lighting). The manufacturer was not made aware of the failure. The failure mileage was approximately 180,000.

NHTSA ODI 11597459

The contact owns a 2012 Mercedes-Benz C300. The contact stated that after opening the sunroof and then attempting to close the sunroof, the sunroof failed to fully close. The contact had to open and close the sunroof several times before the sunroof closed. Additionally, the contact stated that there was water entering the vehicle from the sunroof which caused electrical failures. The contact stated that the vehicle was drivable, but the "Anti-Theft" warning light illuminated. The contact stated that several other warning lights were later illuminated, and the vehicle would not start. The contact had the vehicle towed to a dealer who diagnosed the vehicle and determined that water had damaged the driver’s side electrical wiring harness. The vehicle was not repaired. The manufacturer was informed of the failure. The failure mileage was approximately 169,000.

NHTSA ODI 11594372

Took my car for a doorknob repair and was told the whole subframe is rotted. They told me not to drive the car on the highway. The car brakes very hard to the right and always goes right while making cranking noises. Car feels very unsafe. I paid a lot of money for this and own a 2012 c300 4matic.

NHTSA ODI 11592433

This is a low mileage car with odometer reading of 25668 (less than 2000 miles per year), used sparingly and always parked in the garage. On 05/07/2024 I noticed brake fluid flowing from the left rear side of the car; on examination this seemed to come from the flexible hose that connects the brake fluid line to the brake caliper. I called my Mercedes-Benz (MB) dealer and arranged for further inspection and service. The technician identified that the brake fluid lines to the rear were both totally corroded and in need of immediate replacement. Since the lines were embedded behind the subframe it necissated lowering the subframe to access. Other parts were also severely corroded and required replacement. (see attached PDF of Invoice) The total cost of the repair was $4,592.93. The dealership applied a discount of $150.00 to this for an amount due of $4,442.93. As an engineer, I believe the material used for the brake fluid lines were unsuitable and furthermore were unprotected for the harsh environment experienced under the car, and I believe MB with all their experience in automobiles manufacturing over the years clearly should have known and forseen this fact; I do believe that MB is responsible for this premature failure of the brake lines of my car aven driven only 25,666 miles to date. I am therefore requesting NHTSA to require MB to reimburse me for the unnecessary expense of the costly repairs. It is only fortunate that this failure was identified in my garage and not on the highway. Please advise me of your resolution. Thank you.

NHTSA ODI 11589443

What component or system failed or malfunctioned, and is it available for inspection upon request? As I started my car from a cold start and even when starting the engine, the car was creating this tractor like sound. No system has failed but I read the camshaft adjuster and tensioner pulley has come out of site, which can ruin the engine. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes, it was audible by the dealer but I was told that it would be a normal issue on a cold start. Now they will charge $200 for a service diagnosis. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? Mercedes Benz gave an extended warranty on the program for extension of 10 years but the problem has been happening for multiple people and it has been happening again that this warrants a recall over a poorly designed part that can destroy the car’s engine. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? No such codes or messages. Which is why this is so scary. This incident has been happening for the past 8 months or so and besides a letter about a warranty no such information.

NHTSA ODI 11588738

Subframe rusted and broke. It is available for inspection. Burlington Mercedes inspected the vehicle and told me it was not safe to drive. Mercedes-Benz USA is aware of the problem. They issued a letter extending the warranty covering only the subframe to twenty years and unlimited miles. Burlington Mercedes refused to do the subframe replacement without installing all new arms, which are currently not damaged. The cost to install all new arms is $2826.54. Mercedes-Benz USA is offering a warranty extension that their dealerships refuse to honor. This needs to be turned into a recall instead of a warranty extension. This subframe issue is dangerous. It affects Mercedes vehicles dating back to 2005 and encompasses many of their models including: SLK- Class, CLS-Class, SL-Class C-Class Sedan/Coupe, GLK-Class E-Class Sedan/Wagon, E-Class Coupe/Cabrio

NHTSA ODI 11588793

The contact owns a 2012 Mercedes-Benz C300. The contact stated while driving at an undisclosed speed, he heard an abnormal sound coming from the rear of the vehicle, prompting him to pull to the shoulder of the roadway. After a visual inspection, the contact observed that both trailing arms had become detached. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who determined that extensive frame corrosion had caused both trailing arms to detach. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 143,000.

NHTSA ODI 11587466

Vehicle will not start, possible ESL/EIS failure.

NHTSA ODI 11586117

car has a rear subframe damage from corrosion

NHTSA ODI 11574257

While I was driving my 2012 MB C300 4Matic Sport Sedan in Nov', 2023 with history of regular maintenance, noticed a pretty load knocking noise, shudder and drifting to left a bit when it brakes from the driver's rear side especially on the highways. I took it to our local mechanic who was horrified to report that the sub frame was broken and completely rotten out too specifically rust issue with the rear suspension-rear subframe. He gets other German Cars like BMW & Audi even older and more miles in Chicago but none have rusted so much as these MB C-Class cars. Knowing the Dealers wont accept it a manufacturing defect, he was planning to repair it (no chance of wielding that thin metal sheet as the likelihood of breaking it is high). I was surprised to see 2010 Chevy Impala having a much more robust under the cover protection and no rusting with 115k miles. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11573402

Took my 2012 Mercedes c300 to my mechanic and the Rear Sub frame is rusting out.

NHTSA ODI 11572690

vehicle sub-frame is cracked rusted corroded.

NHTSA ODI 11572697

the rear subframe broke while in motion and caused the car to drift and bounce while i was cornering the traction control and stability control intervened and i also counter steered once back in straight line i braked and the car tilted on the side, we lifted the car in a mechanic shop and found a rotten subframe one side broke the other was almost giving up.

NHTSA ODI 11569388

The contact owns a 2012 Mercedes-Benz C300. The contact stated that the front driver's side interior door handle was fractured. The contact was unable to open the door from inside the vehicle. An independent mechanic inspected the vehicle and referred the contact to the manufacturer for assistance. The dealer was not notified of the failure. 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 approximately 95,000.

NHTSA ODI 11561346

a rusted rear subframe is more prone to crack when a driver hits a pothole or wants to brake quickly, which can lead to instability in the vehicle's rear suspension.

NHTSA ODI 11554689

My rear subframe has corroded and has snapped, which is a major safety issue as while driving when I come to a stop the rear end of the car swags sideways. It do not stop straight.

NHTSA ODI 11551154

1) cranshaft and camshaft position sensors, timing problems and it has to be replaced this is a common damage in Mercedes Benz 2012 c250. 2) this put in risk my life because it can brake the engine in a highway and the car could be off.

NHTSA ODI 11550669

I started hearing noises about a week ago while driving. Last night while driving home in the evening traffic, I braked and car violently jerked and veered to the right almost hitting the car in the front. I took the car to a shop this morning and they found that the rear subframe had collapsed due to rust and advised the car was extremely dangerous to drive.

NHTSA ODI 11548575

Rear driver side wheel was making a clicking noise leading us to believe there was an issue with the strut and/or shock. Due to the nature and severity of the noise, we took the vehicle to our mechanic ASAP. Upon inspection, mechanic identified that the sub-frame had completely rusted through which could lead to other catastrophic issues making vehicle no longer safe to drive unless repaired. Due to the age of the vehicle being 11 years old, the cost to repair was almost the value of the vehicle basically making this a complete loss. I understand that Mercedes Benz has extended the warranty to 20 years for this issue for other models identifying that it is a design/parts defect but not the C300 although I have found that this is also an issue for this model.

NHTSA ODI 11546160

The contact owns a 2012 Mercedes-Benz C300. The contact stated while driving 35 MPH, he smelled a rubber burning odor. A message indicating that the turn signal was inoperable was displayed. The contact stated that he pulled to the side of the road and inspected the vehicle. The contact noticed that there was smoke coming from the rear passenger's side taillight. The contact stated that he opened the taillight panel and noticed that the interior and the bolt had melted. The contact was able to continue driving. The contact related the failure to Mercedes-Benz Campaign Number: 2014050001; however, the dealer informed the contact that the VIN was not included in the recall. The vehicle was not repaired. The manufacturer was notified of the failure and informed the contact that the VIN was not included in the campaign. The failure mileage was approximately 30,000.

NHTSA ODI 11544614

Rear subframe is corroded, rusted through, and cracking.

NHTSA ODI 11541080