Home · 2015 Mercedes-benz C-class Hybrid · Complaints

What 435 owners told NHTSA about the 2015 Mercedes-benz C-class Hybrid

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (435)Crash / fire / injury (13)Engine (134)Fuel system (75)Body & structure (73)Electrical system (54)Steering (28)Suspension (28)Airbags (26)Transmission & drivetrain (23)Visibility & wipers (17)Brakes (10)

Newest first · 435 complaints · page 7 of 18

May 26, 2023Transmission & drivetrainEngineFuel system

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. My additional concerns are: If an odorless fume is passing into the passenger cabin and the vehicle can not pass state emissions these are immediate concerns. The service center advices that I may continue to drive the vehicle. However, I am concerned should the oil fully empty without warning the vehicle may fail while in use on a dangerous roadway due to cause and effect of additional unknown maintenance related operational co-dependent mechanical components.

NHTSA ODI 11524033

May 7, 2023Engine

Crank case breather assembly needed replacement at 31,200 miles. Service mech. Advised the leaking area (oil) could not be repaired since Mercedes does not sell replacement parts and entire assembly needs to be replaced. March advised Mercedes is aware of issue and has redesigned the entire assembly. Cost for part was $400+ and labor to install was $1000. This issue is common as seen on internet and should warrant a recall refund to customers.

NHTSA ODI 11520828

May 5, 2023Engine

Positive Crankcase Valve faulty causing car to buck during moderate acceleration especially when accelerating onto an interstate on an on ramp.

NHTSA ODI 11520609

Apr 27, 2023Steering

The contact owns a 2015 Mercedes-Benz C300. The contact stated while driving 65 MPH, the power steering assist warning light illuminated, and the steering wheel became firm. The contact was able to pull over safely on the side of the road. The vehicle was towed to the dealer and the dealer stated that steering column was experiencing an electric failure, and that the rack and pinon needed to be replaced, and the steering module needed to be reprogramed. The vehicle was not repaired. The manufacturer was contacted, and the manufacturer stated that the VIN was not under any recall. No further assistance was provided. The failure mileage was 100,000.

NHTSA ODI 11519273

Apr 22, 2023Body & structure

FRONT STATIONERY PANEL FAIL OFF WHOLE DRIVING I SEE IT IS IN RECALL BUT DO NOT SEE MY VIN HOW CAN I GET THIS FIXED PER RECALL

NHTSA ODI 11518471

Apr 10, 2023Body & structure

The contact owns a 2015 Mercedes-Benz C300. The contact stated while driving 45 MPH, the roof carriage started shuddering. The contact veered to the side of the road. Upon inspecting the vehicle, the contact noticed that the roof panel had loosened. The contact stated continued driving and the roof panel fractured and partially separated from the vehicle. The vehicle was taken to an auto glass repair shop, where the roof panel was replaced; however, the failure reoccurred. The vehicle was taken back to the same auto glass repair center. The contact then became aware of NHTSA Campaign Number: 21V197000 (Structure) that he related to the failure. The dealer and the manufacturer were notified of the failure and informed the contact that the VIN was not included in the recall. The vehicle was not repaired. The failure mileage was approximately 85,000.

NHTSA ODI 11516408

Mar 31, 2023Engine

My vehicle is a 2015 C300 AWD. One day I was driving on the highway and noticed white smoke coming out of the exhaust. The check engine light came on shortly after as I pulled over. Being that I was less than a mile from my house, I decided to go park the vehicle. I noticed that it was losing power and had problems going above 45mph. Since my vehicle had 99k miles. I took it to my indy mechanic that has worked on the vehicle since it has been out of warranty. When he diagnosed the vehicle, 48 codes came up. He suggested we change the spark plugs and coils, which we did. Didn't fix the problem. Then he suggested we change fuel injector 1, which we did. That didn't solve the problem. I decided to take it to the local Mercedes dealership where they did another diagnostic test. And like many others here, cracked piston/cylinder 1 dead. I'm looking at $18,000 in repairs. I told them no thank you. The car is now sitting in my garage. I really hope Mercedes makes this right with its customers. There is no reason why this many people should be having this exact same problem. Vehicle Symptoms: White smoke out of exhaust Check engine light on Cylinder 1 Misfire Burning Oil Causing loss of power Radio randomly shuts off & went into Anti Theft Mode

NHTSA ODI 11514880

Mar 30, 2023EngineFuel system

2015 C300 Crankcase Ventilation Valve Replacement P052E71 NEED TO BE REPLACED, ENGINE LIGHT COMES ON. ONLY HAVE 37,000 MILES MANY REPORTS OF THIS ISSUE

NHTSA ODI 11514640

Mar 27, 2023Transmission & drivetrain

PVC valve shouldn’t fail and each time it does it is around 2k dollars.

NHTSA ODI 11514007

Mar 27, 2023Engine

my car is a 2015 C300 class Mercedes-Benz, as I was driving, the car suddenly and without warning began to vibrate and shake violently and immediately lost power. Fortunately I was off the freeway, a serious accident could have resulted. I took it to the the local MB dealership and they told me that the car failed a compression test in the #1 cylinder and that the engine would have to be replaced at almost $17000. Of course, this was beyond warranty, Mercedes know it’s a defective product, they refused to act responsibly. This cracked piston which is a design flaw by Mercedes needs to be recalled, a lot of people are reporting the same issue.

NHTSA ODI 11514065

Mar 26, 2023Engine

The problem is actually a manufacturing defect in the wrist pins. The defective parts are in engines made before April 20, 2015 which is mine. If left unrepaired, it causes premature wear in the cylinder walls. The issue on my car been confirmed by mb dealer.

NHTSA ODI 11513842

Mar 23, 2023Engine

obd2 scanner reported Error Code P052E which seems a very common issues on Mercedes C class 2015 or newer and there is no recall issued by Mercedes Benz yet which points out to possible problems with "PCV Regulator Valve components. There are 100s of post in the forum related to same issue

NHTSA ODI 11513338

Mar 23, 2023EngineFuel system

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. It's a safety factor in that it can affect driving, there's risk of blowing valves/valve cap and engines, including loss of the vehicle and nowadays no one can afford to buy a new car or even a used one! Consumers buy what they think is a reliable vehicle but Mercedes isn't taking care of their customers. Mercedes-Benz should be forced to do a recall and replace these faulty parts. Read other complaints here: https://www.benzworld.org/threads/2015-c300-crankcase-ventilation-valve-replacement-p052e71.3047538/page-2

NHTSA ODI 11513522

Mar 17, 2023Engine

Engine light came on there is a problem with pcv valve. This requires extensive repair

NHTSA ODI 11512371

Mar 10, 2023Fuel system

When start the engine, or idling, it smell gasoline in the cabin so bad.

NHTSA ODI 11511283

Mar 2, 2023Engine

The contact owns a 2015 Mercedes-Benz C300. The contact stated that while driving at an undisclosed speed, the vehicle hesitated and stalled. The check engine warning light was illuminated. The vehicle was towed to Safety Auto Repair where it was diagnosed that the engine failed and needed to be replaced. The vehicle was not repaired. Neither the dealer nor the manufacturer was notified of the failure. The failure mileage was approximately 90,449.

NHTSA ODI 11509898

Feb 28, 2023Engine

Driving the 2015 c300 with approx. 69k in miles down the highway and heard a pop and the check engine light came on. The next day there was a rough idle and clanging at low speeds. took to dealership and they quoted me $15k in repairs for a new engine. MB tech said the cylinder #1 is out of spec., and there is scoring on cylinder wall caused by the piston being off center and riding the cylinder wall. After doing research this is a common problem with the m274 engine. How has this not been recalled and taken care of by Mercedes?? At this point i am 'forced' to either come up with $15k for the repairs, or go to MB dealership and try to get into a new car...which i am over $12k upside down on i might add

NHTSA ODI 11509590

Feb 26, 2023EngineFuel system

Check engine light came on and strong fuel smell. Crankcase ventilation malfunction code was verified by dealer.

NHTSA ODI 11509160

Feb 26, 2023Fuel system

The car smell like gasoline inside, the gas hose connecting the high pressure gas line to the gas tank is licking due a bad connectors

NHTSA ODI 11509173

Feb 17, 2023Electrical systemEngineFuel system

When driving I accelerated and then the engine light turned on. after that the car was jolty and turned off completely when stopped. had to force a restart at the light. code that came back was p052E. This is a major and common issue with these cars. part is 400+ dollars. labor is much more since this is a 6 hour job. the work to replace this part is incredibly intensive that makes it impossible for regular car owners to change. Mercedes refuses to recognizes this as a common issue. but the truth is they designed a faulty system that they claim to have updated a handful of times now.

NHTSA ODI 11507757

Feb 15, 2023Engine

My check engine light was on when I was driving on the highway. I was terrified that something was very wrong. Right after, I took the car to the dealer and was told that the valve for the crankcase ventilation. The actuator was blocked. I was also told that this is not caused by something I did. It's the design of the car that caused the problem.

NHTSA ODI 11507493

Feb 15, 2023Engine

P052e71 positive crankcase ventilation regularly valve issue. This is a common issue Mercedes is aware of with their vehicles. I was quoted 1600+ for a repair for something has been known about for over 7 years to be an issue with the car class. I was also told by the shop that this a very common issue and odds are I would need the same service within a year or two.

NHTSA ODI 11507500

Jan 22, 2023Fuel system

Strong Gas Smell when heater comes on. Could be hazardous due to breathing in Fuel Fumes

NHTSA ODI 11503021

Jan 19, 2023Electrical system

Hi i have seen lot of customers have filed this cause happening in all 2015 to.2018 c300 its crank case vent valve needs to be changed every 30 to 60k miles lt of posts i have seen i just want mercedes to recall this problem.as its $2400 to fix this because something they didnt did right and part goes bad . Pls help.us reach this so they can do recalls why we have to pay 2400

NHTSA ODI 11502701

Jan 18, 2023Engine

Oil separator failure. This a common design fault as documented by multiple complaints on the internet. This is another Mercedes Benz emission design flaw causing emission failures. This is very cheap part but extremely expensive to replace. Mercedes collects over $1200 per labor repair for each. THIS IS AN EMISSIONS POLLUTION AND SAFETY ISSUE THAT CAN BE SOLVED. PLEASE FORCE A RECALL. Engine severely smokes/stalls leaving people stranded on highways. When stuck, coolant is sucked into the engine mixing with the oil. No warning. The car

NHTSA ODI 11502437

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Working with the data? Download all 435 complaints as CSV · fetched from NHTSA July 25, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2015 Mercedes-benz C-class Hybrid verdict →