Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2015 Mercedes-Benz C300 owners, lightly cleaned up (personal details are redacted by NHTSA).
My son's car was blowing white smoke out of the exhaust and had a sweet burning smell and the check engine light came on. The crankcase vent valve is needing to be replaced on this 2015 C300 Mercedes Benz and many owners of this same type of car (different year) are posting about it. Owners of these types of cars are saying that replacement is happening more than once! That it's a common defect of these cars. My son has less than 100,000 miles (61,000 if that) and this shouldn't be happening. And, it's time someone does something to protect the consumer. Mercedes-Benz dealers are taking advantage of consumers and charging ridiculous prices to replace this part, but the part shouldn't be breaking. …
I was driving my car was sputtering or trying to shut off while I press the gas and I let go of the gas and it catches and stayed on. I took it to the dealership and they said they found nothing wrong. May 3rd around 12pm im driving on the freeway and as im getting on the express lane going 60 it dies and I couldn't move the steering wheel and I slammed into a guardrail. After doing research my car (vin [redacted] ) had multiple recals from the fuel pump and steering wheel and the dealership never fixed or checked any recalls before selling it to me.
The contact owns a 2015 Mercedes-Benz C300. The contact stated that after refueling, the contact smelled a gasoline odor throughout the interior of the vehicle. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the canister purge valve. The vehicle was not repaired. After investigating the failure, the contact related it to NHTSA Campaign Number: 15V138000 (Fuel System, Gasoline), but the VIN was not included. The manufacturer was not notified of the failure. The failure mileage was 10,000.
The contact owns a 2015 Mercedes-Benz C300. The contact stated that a strong fuel odor could be smelled from both inside and outside the vehicle. The vehicle had to be serviced for the failure; however, upon inspection, the contact believed that the source of the odor was from the engine fuel lines. The dealer was notified of the failure and informed him that there were no recalls on the vehicle. The manufacturer had yet to be notified of the failure. The vehicle had yet to be repaired. The failure mileage was approximately 102,000.
Car has 51,000 miles , no check engine light or any other warning light .driving in on the freeway at 70 mph when I hear a pop sound and my car loses power , I pushed on the gas and it started to shake violently and I panicked as the construction on the freeway was not allowing drivers a shoulder to pull over on . I was lucky enough to be driving at 2am and with the construction going on , drivers were already slowing down . My car also started blowing a thick white smoke through the back exhaust that could have made it harder to see that late night as it was already foggy here in California . At first I didn't realize I was smoking through the back until my car began smelling like burnt oil . I wasn't able to get off the freeway until the next exit all while thinking that my car was going to explode from the smell of the burning oil . …
Mercedes Benz via American Service Center in Arlington, VA regarding the service they performed on my 2015 C300 W4 4Door Sedan AWD the following issues have presented: ISSUE: 03MBZZWARN1 ENGINE LIGHT TECH: 901844 PROBLEM: ENGINE HARNESS, ENGINE CONTROL MODULE, CRANKCASE VENT VALVE, AND O2 SENSOR BANK 1 CAUSE: FOUND OIL IN THE ENGINE HARNESS AND ENGINE HARNESS. OIL IS ENTERING THREW [SIC] THE CRANK CASE VENT VALVE. RECOMMEND REPLACING. Approximate miles at the time of this issue: 63,141. Cost of Repair: $8309.58 Yes, the vehicle is available for inspection. Safety concerns: The vehicle is not able to pass an emissions test with the engine light engaged. Per America Service Center in Arlington, VA, which is the only service center that has serviced the vehicle during my ownership, they commented and documented that oil is entering through a vent valve. …
Heavy fuel/gasoline smell around engine bay began approximately 2 years ago while the car was still under original 5 year warranty. Fuel smell would persist outside of the vehicle despite the vehicle not being driven for multiple days. When driven, fuel smell would permeate into the cabin of the vehicle and cause mild headaches to the occupants. Taken to dealer to find cause of smell and was advised that there was nothing wrong with the vehicle. Fuel smell continues to persist since it was originally noticed without change and vehicle is no longer within warranty period. Recently, this vehicle was taken back to the same dealer for servicing for an unrelated issue. Told the service representative that there was a fuel smell that continues to linger around the vehicle when parked and inside the cabin. …
Hi so i woke up this morning and my started my car as usual then noticed the smell of gas all around the car Inside and out. I got worried turned off the car and started sniffing around to see if i can find where the leak was and found out the high pressure fuel pump was leaking i looked up info on this part and it is very common on these car for that part to fail. Im very upset that there is no recall yet when the dealership told me that they do 2-3 of those jobs a week (HIGH PRESSURE FUEL PUMP REPAIRS) and still no recalls on this,what is it going to take to get one?, my car has to blow up to get your guys attention?? Oh wait other Mercedes c300 cars in the united states already caught on fire please fix this saftey hazard i want to feel safe and not worry about catching on fire. ITS BEEN 6 years AND STILL HAVE NO RECALLS FOR THIS CAR ???
Looks like I am not the first one to complain about the strong smell of fuel on the driver side under the hood as well as inside of the vehicle. Upon further inspection it was determined that the fuel line at the pump is leaking fuel. My car has only 48k miles on it...How can such dangerous failure be ignored by MB for more than three-four years or longer?? Please note that this particular issie is leading the complaints chart. Based on the amount of identical complaints, it appears that this "manufacturer" is waiting for an injury or fatality before they do something about it. This fuel hose situation MUST be addressed IMIDIATELY. Please start the recall before it is too late!!!
There seems to be a continuous gas smell in my car and I see some class action law suits for the same problem but dealership says there is no recall- synopsis of class action below February 26, 2021 - A Mercedes C300 fuel smell has led to a class action lawsuit that alleges 2015-2019 (W205) C-Class vehicles have defects that cause fuel leaks and odors. According to the Mercedes-Benz class action lawsuit, fuel can leak into the engine compartment from fuel line connections to the fuel pump at the rear of the engine compartment. Mercedes C300 and other C-Class vehicle occupants complain of strong fuel smells caused by the fuel leaks. Please assist
Related recalls
Fuel system, gasoline › Delivery › Fuel pump
Mercedes-Benz USA, LLC. (MBUSA) is recalling certain model year 2015 C300 4matic and C400 4matic vehicles manufactured April 7, 2014, to July 25, 2014. In the affected vehicles, the fuel delivery module may be improperly secured to the fuel tank.
Remedy: MBUSA will notify owners, and dealers will inspect the vehicles for improperly secured locking plates and pinched wires, correcting the vehicles as necessary, free of charge. The recal began on April 24, 2015.
Fuel System complaints in other C300 years
Frequently asked questions
How common are fuel system problems on the 2015 Mercedes-Benz C300?
NHTSA has 70 complaints about the fuel & propulsion system of the 2015 Mercedes-Benz C300, 18% of the model year's 381 complaints.
Is there a recall for 2015 Mercedes-Benz C300 fuel system problems?
Yes — NHTSA recall 15V-138 (fuel pump, Mar 10, 2015). Recall repairs are free at authorized dealers.
At what mileage do 2015 Mercedes-Benz C300 fuel system problems start?
Half of the complaints with a recorded mileage happened before about 48,000 miles, and 23% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 0 fires and 1 injury to fuel & propulsion system problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.