69 of the 669 complaints filed about the Mercedes Benz C 300 are about the fuel system — 10% of everything owners reported. The worst model year for it is 2017.
69
Complaints
10%
Share of all complaints
1
Crashes
1
Fires
FUEL SYSTEM, GASOLINE
The contact owns a 2021 Mercedes Benz C. The contact stated that while driving on the highway, the vehicle began to lose power, riding rough. The check engine light illuminated. The vehicle was towed to the dealer where it was diagnosed with a fuel injection failure. The vehicle read diagnostic code P1CEF85. The manufacturer was made aware of the issue. The approximate failure mileage was 60,000.
NHTSA complaint #11738727 — an unverified report by a vehicle owner.
FUEL SYSTEM, GASOLINE
The contact owns a 2017 Mercedes-Benz C300. While driving at approximately 15 mph, the contact observed smoke emanating from under the hood. The vehicle was driven to her work location and parked. Upon exiting the vehicle and opening the hood, she observed orange flames coming from the engine compartment. A parking attendant extinguished the fire, and a police and/or fire report was filed. The vehicle was towed to a dealer and diagnosed with a fuel line leak that caused the engine harness to come apart. The leaking fuel hose from the high-pressure fuel pump caused damage to the high-pressure pump, engine harness, vacuum transducer, and coolant feed line from the thermostat to the firewall. The following components needed replacement: high-pressure fuel pump, rubber fuel hose, engine harness, pressure transducer, and intake manifold. The vehicle was repaired. Five months later, the contact experienced another failure she believes was associated with the engine fire. While parked and attempting to start the vehicle, it did not start. The vehicle was towed to a dealer and diagnosed with a faulty starter that needed replacement. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 65,422.
NHTSA complaint #11738037 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
strong evident fuel/ gas smell when driving and when the car is in park after driving.
NHTSA complaint #11735746 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
UNKNOWN it was just one day I started my car and turned the A/C on and I started getting this strong gasoline smell. I went on like a saw there is a recall for this problem for the M274 engines.
NHTSA complaint #11708103 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
This vehicle was brought to an authorized Mercedes-Benz dealership for regularly scheduled maintenance. Shortly after this service, the vehicle began experiencing significant issues including difficulty accelerating, engine hesitation while driving, and noticeable shaking at idle. This car has never overheated. The vehicle was returned to the dealership for inspection. The dealership diagnosed a cracked cylinder head and advised that the repair requires replacement of the cylinder head at an estimated cost of approximately $11,000. The failed component is available for inspection and the vehicle is currently at the dealership. The vehicle has approximately 46,000 miles, has been regularly maintained, garaged, and driven under normal conditions. These symptoms created engine performance issues that could result in loss of power or inability to accelerate while driving, creating a potential safety risk, especially in traffic or at highway speeds. I regularly transport my young grandchild in this vehicle. The possibility of sudden engine failure, loss of power, or breakdown while driving raises significant safety concerns for myself and any passengers, particularly a young child. The failure has been confirmed by an authorized Mercedes-Benz service center. During my own research, I discovered there have been recalls involving similar engines for the same model year, as well as multiple owner complaints reporting similar engine or cylinder head failures on this vehicle. I contacted Mercedes-Benz customer care on December 17, 2025, after receiving the dealership diagnosis, and was advised that I would receive a response within 72 hours. As of today, I have not received any response. I attempted to call customer care again, but the phone system would not accept a voicemail and no representative answered. My case number with Mercedes-Benz is 19653254. No prior abuse, misuse, or abnormal driving conditions occurred. The vehicle was properly maintained.
NHTSA complaint #11706568 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
My car had a coolant leak last year a hose broke and I have a 2021. My son’s mercedes sis the same thing on 11/23/2025. I have researched ma y others with this same issue. There should be a recall on that hose or whatever the problem Is.
NHTSA complaint #11701496 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
1. The vehicle experienced a fuel injector failure, which is part of the engine fuel delivery system. This failure appears connected to an open Fuel System Control Unit Software Update Recall (Campaign 2024080006) that has been open since May 2024 but was not performed on my vehicle, despite the vehicle being serviced at the dealership in January 2025 for other recall-related updates. The failed injector is still available for inspection upon request. 2. The vehicle began exhibiting symptoms of fuel system malfunction while driving, including rough idling, hesitation, and loss of power. A malfunctioning injector can cause the engine to misfire, stall unexpectedly, or run unpredictably, which creates a high-risk situation in traffic. This placed me, my passengers, and other drivers at risk, especially during acceleration or when merging into traffic. 3. Yes. The issue was diagnosed and confirmed by the Mercedes-Benz dealership, which stated that the injector had mechanically failed. The dealership also noted the open recall for the fuel system software update but claimed it was unrelated. I am seeking clarification because the timing and symptoms suggest there may be a connection. 4. The vehicle has been inspected only by the Mercedes-Benz dealership. Mercedes-Benz USA (MBUSA) has been contacted regarding the issue, but my case was closed without resolution and is currently awaiting review for reopening. MBUSA has not yet inspected the vehicle or the failed component directly. 5.Prior to the injector failure, the vehicle displayed engine hesitation, rough idling, and intermittent performance issues. Eventually, a check engine light illuminated. These symptoms began before the manufacturer-installed software update, and the issue appears to have worsened afterward.
NHTSA complaint #11700351 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
Cabin smells heavily like fuel and has a check engine light possibly a fuel leak
NHTSA complaint #11698322 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
I purchased this 2020 Mercedes-Benz C300 only two months ago and have driven it less than 3,000 miles. The Carfax report shows consistent maintenance and regular service history by prior owners. While driving, the check engine light came on and the vehicle began shaking and running roughly. Diagnostics by Peachtree Imports (10/03/2025) and later by Mercedes-Benz of Atlanta South confirmed Cylinder #2 failure on the M264 2.0L engine at only 26,589 miles. The dealer’s report states: “Cylinder #2 mixture formation out of spec. Fault occurred due to worn exhaust valve seat. Cylinder head replacement required.” Estimated repair cost: $10,470.66. This causes misfire, loss of power, and unsafe drivability. The failure matches Mercedes-Benz Technical Service Bulletin LI01.30-P-072328 (2021), which documents valve-seat leakage in M264 engines requiring head replacement. The vehicle is outside warranty but has extremely low mileage, and MBUSA Case #18392667 remains unresolved. It is also important to note that the M260 engine, which is mechanically identical to the M264 but mounted transversely, has already received a warranty extension from Mercedes-Benz for the same cylinder-head and valve-seat defect. This indicates a systemic issue across both engine families, presenting a safety risk of sudden power loss or engine stall during operation.
NHTSA complaint #11695702 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
While driving car on Sunday 10/5, it suddenly failed to respond to gas pedal pressure. The car stopped accelerating and rather slowed to 15 MPH, almost causing a car from behind to hit me in the rear side.
NHTSA complaint #11691568 — an unverified report by a vehicle owner.
FUEL SYSTEM, GASOLINE
The contact owns a 2019 Mercedes-Benz C300. The contact stated that while driving at various speeds, the vehicle suddenly lost motive power and decelerated. The accelerator pedal was depressed while attempting to accelerate. The contact stated that the fuel gauge failed to accurately display the level of fuel in the tank. The check engine warning light was intermittently illuminated. The vehicle was taken to the dealer, who diagnosed that the fuel level sensors had failed. The fuel tank and fuel pump needed to be replaced. The vehicle was not repaired. The contact became aware of NHTSA Campaign Numbers: 23V880000 (Fuel System, Gasoline), and 23V445000 (Fuel System, Gasoline); however, the model year was not included. The manufacturer was informed of the failure. The manufacturer referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 157,000.
NHTSA complaint #11688189 — an unverified report by a vehicle owner.
FUEL SYSTEM, GASOLINE
The contact owns a 2019 Mercedes-Benz C300. The contact stated that while at a stoplight, there was an abnormal odor of fuel inside the vehicle. The contact stated that the vehicle failed to respond as needed. The vehicle was restarted and shut off independently. The check engine warning light was illuminated. The contact stated that the failure was related to NHTSA Campaign Number: 21V961000 (Fuel System, Gasoline). The vehicle was towed to an independent mechanic who determined that the failure was a fuel rail failure. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted and confirmed there were no open recalls on the VIN. The failure mileage was approximately 60,000.
NHTSA complaint #11656739 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
Po52E71- Emissions issue with crankcase. Mercedes implemented an extended warranty on various models but excluded 2019 C300, which definitely has the same issues. See below in reference to previous models. IMPORTANT EMISSION EXTENDED WARRANTY INFORMATION In our continuing efforts to assure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA, LLC (“MBUSA”) is extending the warranty coverage on the intake line assembly in certain Model Year (“MY”) vehicles listed below from the original New Vehicle Limited Warranty of 4 years/50,000 miles to 15 years/150,000 miles (whichever occurs first) due to the following condition: • Under certain circumstances, the partial-load ventilation valve (a part of the intake line assembly) may not work as intended, resulting in the illumination of the check engine Malfunction Indicator Lamp (‘MIL’). A faulty partial-load ventilation valve might also increase exhaust gas emission. Model Model Years Sales Designation C-Class 2015 – 2018 C 300, C 300 4MATIC C-Class Convertible 2017 – 2018 C 300 Convertible, C 300 4MATIC Convertible C-Class Coupe 2017 – 2018 C 300 Coupe, C 300 4MATIC Coupe C-Class Hybrid 2016 – 2018 C 350e E-Class 2017 – 2019 E 300, E 300 4MATIC GLC 2016 – 2019 GLC 300, GLC 300 4MATIC GLC Coupe 2017 – 2019 GLC 300 4MATIC Coupe GLC Hybrid 2018 – 2020 GLC 350e 4MATIC SLC 2017 – 2020 SLC 300 SLK 2016 SLK 300
NHTSA complaint #11648766 — an unverified report by a vehicle owner.
FUEL SYSTEM, GASOLINE
The contact owns a 2018 Mercedes-Benz C300. The contact stated that while the vehicle was parked inside the garage, there was a strong fuel odor inside the garage. The contact stated that there was fuel leaking from the vehicle. There were no warning lights illuminated. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not contacted. The failure mileage was approximately 52,300.
NHTSA complaint #11642176 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
The engine light is on with only 35000 miles. Upon using an OBD2 scanner, error code P052e positive crankcase ventilation(PCV) malfunction was detected. It's a problem that I researched and noticed a lot of people having the same issue. I was told that this can cause the car to stall or shut down? This causes serious risk and safety issues to drivers, passengers, and pedestrians. With so many complains about this problem, I believe the manufacturer and dealers should take responsibility before tragedies happen.
NHTSA complaint #11640265 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
Leaking fuel as described in one of the previous recalls for the car. There is a fire hazard but the VIN is not listed as being eligible.
NHTSA complaint #11633699 — an unverified report by a vehicle owner.
FUEL SYSTEM, GASOLINE
The contact owns a 2019 Mercedes-Benz C300. The contact stated while driving, the vehicle failed to exceed 15 MPH. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic to be diagnosed. The vehicle was scanned, and the mechanic retrieved fault codes indicating a failure with the high-pressure fuel pump. The contact was informed that the high-pressure fuel pump needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 34,945.
NHTSA complaint #11624818 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
small to much gas inside the cab and outside and bouth seatbelt doosent work corectly
NHTSA complaint #11624452 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
my whole entire car smells like gas. I cannot drive this car around because I will pass out and it is a safety hazard. There is a recall for this exact same issue, just not for my Vin number. I would like to get this done for my car, please.
NHTSA complaint #11621009 — an unverified report by a vehicle owner.
FUEL/PROPULSION SYSTEM
Gas smell coming from engine area when car has been sitting overnight. Smell comes from driver's side of engine compartment. Gas smell does not happen when car is running. Smell fills up our 2-car garage causing concern when we start the car in the morning.
NHTSA complaint #11611601 — an unverified report by a vehicle owner.