Mercedes-Benz C-Class Complaints (2012)

588 consumer complaints on file.

#11773412October 24, 2026
STRUCTURE:BODY
Did a winter inspection of vehicle and found rust on the rear frame. Rust has already made a hole on the subframe and hair line crack already forming, only a matter of time before it brakes.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11771513October 15, 2026
FUEL/PROPULSION SYSTEM
Fuel leaking in the back seat of the car
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
#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
#11759255August 24, 2026
SUSPENSION
The rear sub frame has rusted and part of it has failed
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11738871May 19, 2026
FUEL/PROPULSION SYSTEM
Vehicle: 2012 Mercedes-Benz C300 4Matic Sport Problem Component: Fuel / Propulsion System Safety Issue Description: My 2012 Mercedes-Benz C300 developed a serious fuel tank leak at approximately 106,460 miles which created overwhelming gasoline fumes and rendered the vehicle unsafe to operate. The gasoline fumes were extremely strong and entered the passenger area. The fumes were severe enough that I became physically overwhelmed from the gasoline exposure and discarded clothing due to gasoline contamination and odor. A local repair facility identified the leaking fuel tank. I was informed the replacement fuel tank was allegedly on extended backorder through Mercedes-Benz channels. Because the vehicle was unsafe to drive and replacement parts were allegedly unavailable for several months, I was forced to tow the vehicle from [XXX] to [XXX] at my own expense in order to locate a repair facility that could obtain a replacement fuel tank and safely repair the vehicle. The repair invoice states: “Installed used lt fuel tank incl switchover fuel pumps replace section of steel fuel line front of tank from lower braided line.” I am submitting this complaint due to: serious gasoline leak safety concerns, severe gasoline fume exposure, potential fire hazard, and the alleged extended unavailability of replacement fuel tanks. Mercedes-Benz USA Case Number: 22302114 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
#11732281April 19, 2026
SUSPENSION
I have a rust free, relatively lower mileage car I bought for my teen daughter. Despite being such a clean car the rear subframe has rusted and rear suspension has broke off while driving, hitting the fuel tank and is unstable. We avoided an accident but the car is not drivable.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11701264November 24, 2025
STRUCTURE:BODY, SUSPENSION
Mercedes of Danbury replaced the rear sub frame CODE 3441 47, since my mechanic (Newtown Auto Repair) told me that the Front subframe is in real bad shape, rotten/rusted, that it is dangerous to drive the car in this condition since the wheel and steering components are part and attached to it, the car would be out of control and all over the road any of these components fail and pull / brake away from the rusted out Sub Frame. When I brought the car in was under the impression that Mercedes Benz would replace front and back Sub Frames. But now they informed me of only recall on rear subframe, rear subframe will let go wheels will collapse, front controls the car and failing could kill people and total the car. frames.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11696118October 28, 2025
FUEL SYSTEM, GASOLINE
The contact owns a 2012 Mercedes-Benz C300. The contact stated the fuel tank was emitting a fuel odor. The contact stated that the fuel odor was extremely strong and could be smelled inside the residence while the vehicle was parked in the garage. There were no warning lights illuminated. The vehicle was taken to a Certified Mechanic, who diagnosed that the leak was coming from the top of the fuel tank; however, the mechanic was unable to specify the cause. The vehicle was towed to the dealer, but the vehicle was not diagnosed. The vehicle was not repaired. The contact became aware of NHTSA Campaign Number: 12V557000 ( Fuel System, Gasoline) online; however, the VIN was not included. The manufacturer was informed of the failure and informed the contact that the VIN was not under recall. The failure mileage was approximately 98,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11687260September 15, 2025
VEHICLE SPEED CONTROL, SERVICE BRAKES, STEERING
-The steering wheel and brake locked up and became unusable while driving at approximately 75mph. Cruise control was enabled for a few miles (maybe 2) and disabled after. Around 5 minutes after disabling, the car began to surge between acceleration and deceleration drastically on its own. All of the dashboard lights that come on when the key is initially inserted came on at once while engine was on/running and the car was in drive. After finally being able to reach a safe enough spot, I put the car in park and turned the engine off. I sat for a few minutes to try and turn the engine/car back on and the car would not crank, but the overhead lights, radio, and dash lights were functioning. -This was an extremely dangerous experience. The car began to decelerate rapidly in heavy freeway traffic. At that speed, with many semi-trucks traveling nearby, this sudden loss of speed created an extremely dangerous situation. My vehicle instantly became a slow moving obstacle in the lane. Only by luck and quick reaction was a serious or fatal collision avoided. The car would not start back up so I was sitting at the edge of the highway as many cars flew by just inches away from my car. -I am away at college in a rural city. Accessibility is limited as well as support because of lack of resources. -The car was towed to a mechanic who does not specialize in German cars and stated they did not have the proper tools to "get into the car" because the motor is "locked up" and the car wouldn't crank. -The vehicle will be towed to the nearest dealership (50mi away) who stated they won't be able to look at it for a few weeks from date of arrival. Research indicates this may be linked to a known issue with Electronic Steering Lock (ESL) / Electronic Ignition Switch (EIS) failure in Mercedes vehicles, which can electronically disable the engine and steering. This could've easily been fatal for me and still poses an alarming threat if not addressed.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11682005August 20, 2025
STRUCTURE:BODY, UNKNOWN OR OTHER
Rear subframe rotted out and broke due to corrosion. Rear crossmember is broken and needs replaced. My safety as well as the safely of other was put at risk. Loss of control at high speed could have been deadly. Luckily, I wasn’t going very fast at the time of incident or else who knows what would have happened to me or bystanders. Independent service center inspected and confirmed that incident was due to corrosion in the rear. They informed me of the extended warranty (20 years, unlimited miles) on 2008-2015 C300 models for this particular issue as my safety and the safety of others was put at risk. There were some symptoms leading up to the incident. At the time of braking the car would become unstable and feel skittish in the rear. It felt as if the rear was sliding to one side. The vehicle would also make some metal clinking noises at sharper turns. The symptoms had been more frequent in the prior 2-3 months of incident. The vehicle has been inspected and diagnosed by one shop and is currently getting a second opinion from another independent service center.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11681296August 18, 2025
ENGINE
The contact owns a 2012 Mercedes-Benz C250. The contact stated that while driving at an undisclosed speed, there was an abnormal rattling sound coming from the vehicle with the check engine warning light illuminated. The contact drove the vehicle to the shoulder of the road. The contact stated that the rattling sound continued, and the vehicle shuddered abnormally. The vehicle was towed to the residence. The independent mechanic provided mobile service and diagnosed the vehicle with cam shaft timing chain adjuster failure. The contact was informed that the cam shaft timing chain adjuster needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure but provided no assistance. The contact was advised to contact the NHTSA Hotline and report the failure. The failure mileage was approximately 150,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11676056July 24, 2025
UNKNOWN OR OTHER
The electronic steering lock failed resulting in my car being completely disabled. My safety was not at risk in this particular instance. I was left stranded in a parking lot at night. The component was not inspected by the manufacturer or dealer. The manufacturer/dealer did not inform anyone that this problem will happen to every car with this compensation. This component failed without warning/symptoms/messages. It will fail on all Mercedes Benz cars from 2008-2016. The problem has not been confirmed or communicated by the dealer. Other Mercedes benz owners have encountered this problem resulting in their cars being disabled and leaving them stranded.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11674095July 16, 2025
SUSPENSION
Rear subframe crossmember rotting, needs replacement. It seems to be a common problem with this vehicle and the assumption by most professional is that it a faulty part supplied by a third party to Mercedes. The rest of the cars undercarriage is pristine, making me wonder why just this one part would rust out.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11673323July 14, 2025
AIR BAGS
I was driving normally last week when the driver's head restraint system (known by Mercedes as Neck Pro) unexpectedly and without warning blew at my head. The noise was very loud, and the headrest slammed against my head. Luckily, I was driving approximately 20-25 miles per hour, daytime, on a residential street without too many other vehicles. I was able to pull over to investigate what happened and ensure I wasn't injured and did not collide with any objects in the road. If this had happened on the highway at highway speeds with a less attentive driver, I could see this potentially resulting in a major collision. The road was fat, no bumps, weather was clear. There is no reason why this happened. From what I can tell, the system looks like it failed (plastic clips broke off) and the system did not intentionally deploy. It has not been repaired and is available for inspection. I have not taken it to the dealership for review. The vehicle is in perfect condition with no warnings. It very recently passed Maryland state inspection.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11670521July 1, 2025
SERVICE BRAKES, HYDRAULIC
The contact owns a 2012 Mercedes-Benz C250. The contact stated while driving 35-40 MPH and depressing the brake pedal, the brake pedal was significantly stiff, and the vehicle failed to respond as needed. The contact stated that upon standing on the brake pedal, the vehicle responded as needed. The contact stated that the failure recurred while driving 65 MPH. The vehicle was taken to the dealer, where the vacuum pump was replaced; however, the failure recurred. The vehicle was taken to Mercedes-Benz of Beaumont (1865 I-10 S, Beaumont, TX 77701), where it was test-driven, and the dealer became aware that the brake pedal was extremely firm. The dealer diagnosed the vehicle and determined that the vacuum pump needed to be replaced. The part was replaced; however, the failure persisted. The contact stated that the failure increased, causing the contact to engage the parking brake to stop the vehicle. The vehicle was not repaired. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 96,826.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11666448June 12, 2025
AIR BAGS, ENGINE, POWER TRAIN
The model/year Mercedes-Benz are well known for experiencing this/these particular issues. My research has shown that these year/make/model vehicles are experiencing the same type of mechanical failures nationwide. The issues all relatively begin around 75,000 miles. I've only had my car 3 years putting 30000 on it hardly driven/cared for **Issue Found:** Oil was leaking onto the ignition coil and spark plug of cylinder 3. **Source of Leak:** Valve cover gasket failure. **Recommended Repairs:** - Replace the valve cover gasket (to halt the oil leak). - Replace spark plugs and ignition coil (which were contaminated/damaged by oil). **Relevance to Warranty:** The valve cover gasket is only covered if it fails as a result of an internally lubricated engine part causing damage. Ignition coils and spark plugs are maintenance items and are not covered by warranty plans. **Required Repairs (Identified Mechanical Issues)** - **Coolant Pipe Leak – $850** **Issue:** Coolant leaking from a pipe on the side of the cylinder head. **Relevance to Warranty:** Typically not covered unless it pertains to a failure in a covered system such as the water pump or cylinder head due to an internal breakdown. This is likely classified as an external plumbing component, which is not included. - **Oil Feed Line Leak – $600** **Issue:** Oil leaking from the side of the engine, traced back to the oil feed line. **Relevance to Warranty:** This is not typically covered unless the oil feed line is part of the oil pump system and has failed due to an internal issue (usually regarded as an external line). **Other Items Found (Worsening Issues)** - **Timing Chain Rattle / Cam Adjuster Noise – $6,000** -**Issue:** Rattling sound during startup. **Diagnosis:** Noise emanating from the timing chain and camshaft adjusters. **Relevance to Warranty:** This is covered under Secure Plus, as both the timing chain and camshaft adjusters are recognized as internally lubricated par
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11661547May 16, 2025
ELECTRICAL SYSTEM
I was replacing rear tail light bulb. Now I'm getting an error message on instrument cluster. I tried to fix the issue but couldn't do to the fact the wiring harness has melted. Mercedes Benz had a recall back in 2013 saying this is a safety issue. No recall for our car.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11652861April 4, 2025
ENGINE, FUEL/PROPULSION SYSTEM
The contact owns a 2012 Mercedes-Benz. The contact stated while driving at an undisclosed speed, the Check Engine and High Pressure Fuel Pump warning lights was illuminated. The failure occurred on several different occasions. The vehicle was taken back to the residence. The contact did research and was made aware of an unknown NHTSA Campaign Number however, the VIN was not included. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was unknown.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11639290January 29, 2025
SUSPENSION
Took the car in for an oil change and asked them to look at the brakes and rear as there was a strange noise. Vehicle was inspected and found the entire subframe is rotted. Was advised this is a common problem with Mercedes and there were some recalls. Unfortunately no open recall on this vehicle and it is now not driveable as this is a safety risk. Car has been driven 60 miles/day for the past 3 months and could have had serious consequences.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

← Back to Mercedes-Benz C-Class