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

What 433 owners told NHTSA about the 2015 Mercedes-benz C-class Phev

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 (433)Crash / fire / injury (13)Engine (134)Fuel system (75)Body & structure (72)Electrical system (54)Steering (28)Suspension (28)Airbags (26)Transmission & drivetrain (23)Visibility & wipers (17)Brakes (10)

134 of 433 complaints match · Engine · clear filters · page 3 of 6

Mar 17, 2023Engine

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

NHTSA ODI 11512371

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 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 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

Jan 16, 2023Engine

I have 2015 C300 Model, total milage on the car is 30K. Dashboard is showing the check engine light and when I take to Dealership for diagnostic, the code is P052E which is a problem with Crankcase vent. Dealership tech had mentioned that this seems to be known issue effecting years 2015-2018. When I did search, he is right; many MB owners are facing same issue which is a malfunction during assembly/manufacturing. MB should be responsible for part replacement and labor. Please investigate and ask MB to run recall campaign. Thank You.

NHTSA ODI 11501944

Jan 12, 2023Engine

Vehicle experienced loss of power and rough running when check engine light came on. Mercedes dealer reported one of the pistons cracked resulting in catastrophic engine failure with just shy of 61,880 miles on it.

NHTSA ODI 11501468

Jan 6, 2023Engine

These cars have a known wrist pin failure, mercedes refuses to cover the cost of repairs as its not a recall. My vehicle is the specific model and year this is known for, and my car is making these piston slapping sounds, worse everyday. Worse on deceleration, goes away when warmed up, just like the reports. I am afraid I'll lose power while driving and hurt myself or others.

NHTSA ODI 11500515

Jan 5, 2023EngineFuel system

I have an emissions related Check Engine Light (P052E71) relating to the Evaporative/Crankcase ventilation system. I think this should be a Recalled/Warrantee item on the 10 year/100,000 miles federally mandated guarantee. Please advise...

NHTSA ODI 11500356

Jan 5, 2023Engine

It cuts out randomly while pressing the gas pedel to get out of the way of traffic and cuts out and stalls ive had it looked at and they say theres no check engine codes and that they cant make it do it. Theres many of people with the same issue online and the dealers wont help them either

NHTSA ODI 11500361

Jan 3, 2023Engine

Common problem mercedes hasn’t addressed from the factory crankcase breather element at less than 50,000 miles and the smell pf gas that comes in to the cabin is horrible

NHTSA ODI 11499880

Dec 27, 2022Engine

The dealership is staying I have an issue with the crankcase valve vent and this seems to be a known issue effecting years 2015-2018.

NHTSA ODI 11499064

Dec 23, 2022EngineFuel system

2015 Mercedes C300 crankcase ventilation regularly valve is garbage, have to spend around $2K to get it replaced. Very common issue for this model.

NHTSA ODI 11498620

Dec 7, 2022Engine

Car is at 60,000 Miles and code for Positive crankcase ventilation appeared. Why does this happen to a trouble free car after warranty runs out?????????? Seems like hundreds of complaints all over the internet and Dealer charging big money to fix their design Flaws.

NHTSA ODI 11496386

Nov 25, 2022Engine

Crankcase (pcv) problem of the 2015 Mercedes Benz C300 Diagnosis code p052e pcv regulator valve replacement/crankcase replacement. The code keeps coming back with check engine light on dashboard. To replace part, the engine has to be taken down since the crankcase is inside the engine. This is a malfunction during assembly/manufacturing, it is impossible to damage part while under usage. Mercedes benz should be held responsible for part replacement and labor. This is a common defect and should be recalled.

NHTSA ODI 11494920

Nov 23, 2022Engine

Crankcase Ventilation Regulator Valve

NHTSA ODI 11494713

Nov 17, 2022Transmission & drivetrainEngine

This occurred after an oil change. it is the P052E code crankcase ventilation code.

NHTSA ODI 11494011

Nov 9, 2022Engine

CEL light- with code P052e positive crankcase ventilation regularly valve.

NHTSA ODI 11492980

Nov 7, 2022EngineFuel system

Code P052E

NHTSA ODI 11492676

Oct 19, 2022Engine

Crankcase ventilation valve malfunctioning Second time with car. Creating trapped exhaust in crankcase.

NHTSA ODI 11489900

Oct 7, 2022Engine

Mercedes crankcase ventilation valve has failed, error P052E71. Found that this is happening to thousands of other Mercedes c300, and even after it is fixed it happens again. Reporting this so hopefully it can be resolved with a recall.

NHTSA ODI 11488418

Oct 1, 2022Engine

Vehicle throwing P052E error (crankcase ventilation valve - PCV) - Has occurred multiple times and has effected numerous C300 models of the years 2015-18. - The car has lower acceleration performance and can be potentially dangerous when merging on highways.

NHTSA ODI 11487460

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Working with the data? Download all 433 complaints as CSV · fetched from NHTSA July 20, 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 Phev verdict →