Home · 2018 Mercedes-benz C-class Hybrid · Complaints

What 125 owners told NHTSA about the 2018 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 (125)Crash / fire / injury (5)Engine (39)Body & structure (15)Steering (13)Electrical system (12)Fuel system (10)Transmission & drivetrain (6)Airbags (5)Communication (5)Tires (5)Wheels (5)

Newest first · 125 complaints · page 3 of 5

Sep 15, 2023Engine

Engine light came on, checked with diagnostic machine shows a crank shaft issue. I have maintained the car with regular checks and maintenance. This has to be a defective part.

NHTSA ODI 11544819

Sep 6, 2023Electrical system

According to the dealership, if the car is not started every 3 days, it will shut itself down. The car was towed 6 times, I'm a business woman, my coworkers, friends drives Mercedes Benz, and no one have heard of any such issues. Any cheaper cars, after 2 weeks at the airport, the car starts. Something is wrong with the car, something is draining the car battery if not started every 3/ 4 days. They are taking advantage to the fact, that I'm a female and older. They need to replace the car, fix, or junk their car. Someone needs to take responsibility for the repair of the car.

NHTSA ODI 11543013

Sep 5, 2023

The check engine light came on with the error code P052E - PCV valve failure while the car is only driven for less than 38K miles. I am worried about the quality of the car/engine.

NHTSA ODI 11542789

Aug 24, 2023Electrical system

Hello My c300 2018 only have 79k and suddenly the engine light on, when I check it show that I need Positive Crankcase ventilation valve replace. it cost $2300. As I know a lot of people who own Merced have the same problem so should have a recall for that Thanks

NHTSA ODI 11540537

Aug 12, 2023Visibility & wipersBody & structure

Incorrect bonding of the rear window. The rear window bond is failing which is causing the window to detach from the convertible top. The bonding is failing in many different locations, causing not only detachment, but the failure is also causing fine hairline cracks at the points of failure. The dealership refused to correct the defect, informed I would have to pay $3,000.00 to correct the failure of the bonding.

NHTSA ODI 11538137

Aug 5, 2023Engine

The check engine light has been coming on to indicate replacement of vent valve assembly According to the Mercedes Benz dealership. This is a commonly known problem in MB that they should replace and repair instead of charging customers $2k. My car has below 40k miles on it.

NHTSA ODI 11536699

Jul 26, 2023EngineFuel system

Check engine light came on. Had a diagnostic check and was told that the crankcase ventilation sensor needs to be replaced which will cost $1200.

NHTSA ODI 11534679

Jul 23, 2023EngineFuel system

My c300 2018 only has 50k and suddenly the engine light is on, when I check it shows that I need the Positive Crankcase ventilation valve replaced. it cost $2300. As I know a lot of people who own Mercedes have the same problem. Three mechanics claim it on almost all C, CLA, and GLA models. Please make Mercedes recall it finally.

NHTSA ODI 11533877

Jun 7, 2023Engine

Has 27000 miles out of warranty at 5 years. PCV code bad actuator. Looks like a common problem. Should be recalled.

NHTSA ODI 11525844

May 25, 2023Fuel system

This particular model of vehicle has a well-known and documented failure of the PCV valve (Crankcase). This has not been identified by NHTSA to date. This should be considered for a recall due to the high incident rate of the P052E error code (valve failure) as this causes reduced emission control and possible explosions within the engine due to pressure-related issues. My vehicle did not have any warnings prior to the engine light illuminating. After diagnostics, P052E was identified. Dealership told me that it needed to be replaced as it would fail and result in damage.

NHTSA ODI 11523881

Apr 30, 2023EngineFuel system

The code I received is p052e from the check engine light. This can cause the car to stall out mid way through driving and cause a potential fatal accident. This is a common issue across C300 And GLC benz.

NHTSA ODI 11519686

Apr 16, 2023

Rear camera doesn’t work

NHTSA ODI 11517301

Apr 2, 2023

The fault code P052E71 is logged in the fault memory of the engine control unit. Cause: Possible cause: The component or the electrical actuation at the partial load crankcase ventilation valve (Y58/2) may be faulty or might not activate initially.

NHTSA ODI 11515018

Mar 10, 2023Electrical systemCommunication

The contact owns a 2018 Mercedes-Benz C300. The contact stated that after starting the vehicle, the S.O.S. Not Active message displayed. The contact was concerned that in the event of an emergency, the emergency services function would be inoperable. The vehicle had previously been serviced under NHTSA Campaign Number: 21V058000 (Electrical System, Communication) however, the failure recurred. The dealer was made aware of the failure; however, the vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 85,000.

NHTSA ODI 11511208

Feb 22, 2023Engine

Engine light P052E, This seems to be a common problem with the C300.My concern is that Mercedes Benz hasn’t address the common issue. I own the car less than a year got it from Mercedes dealership and to be honest I expect Mercedes Benz to be better than the this to it customers

NHTSA ODI 11508602

Feb 21, 2023EngineFuel system

at 67000 miles the check engine light came on and is was engine code p052e crankcase ventilation regulator valve failure. This failure will cause the ending to exhaust increased contaniments in to the air. This is a know problem by MBUSA and they have changed the part design on new vehicles , this problems comes up right after the cars warranty and they cost to repair is in excess of $2500. For this to be an emission know problem by MBUSA a recall should be issued and this problem corrected under the recall process of the NHTSA ASAP. This has been reported to MBUSA and they have been zero help in this matter. The NHTSA is here to protect our citizens and environment and hopefully you will continue to do so.

NHTSA ODI 11508445

Feb 21, 2023EngineFuel system

Failed positive crankcase ventilator after 40,000 miles common problem regulating oil consumption to the engine. Causing oil burn, oil leak, inconsistent oil ventilation. Dealer is aware of the problem. Engine light is on with code P052E. Commonly reported problem for this model on the internet.

NHTSA ODI 11508446

Feb 17, 2023Engine

Code P052E just like all 2.0 turbo Mercedes Benz engines will get. This is a engineering defect and the cars with these engines should be recalled. I have researched and read that even after repaired this expensive engine defect will re-occur about every 35000 miles.

NHTSA ODI 11507887

Jan 29, 2023Body & structure

This is 2018 Mercedes Benz - C300 and it seems across this model line up and models from that year it looks like headliner particularly fabric starts to separate from the pillars in the rear. Across google there is bunch of C300 with the same issue in the same spot starting. The Car is only 5 years old and if it would be any other brand I would not be to upset about it. But this is Mercedes and they pride themselves of being a " Luxury " Vehicle where their standards should be much higher. Needles to say we contacted and went to one of the Mercedes Dealership that we got charged $226 for the inspection and Mercedes did not honored to replace the defect nor MBUSA - did not helped either. This is the problem across the model . Be AWARE and take this into consideration when thinking of purchasing this particular model year C300.

NHTSA ODI 11504289

Jan 24, 2023Transmission & drivetrain

Error Code P052E Positive Crankcase Ventilation Regulation Valve Performance

NHTSA ODI 11503405

Jan 24, 2023Engine

2018 Mercedes C300. P052E check engine code. Positive Crankcase Ventilation failed with less than 28K miles. Common reported problem but not covered after warranty period, even with extended warranty addition. It's a major part of the engine function and 6 hours of labor to replace. Mercedes Benz should cover this type of fault on the design.

NHTSA ODI 11503416

Dec 23, 2022Engine

initial observation started happening intermittently a week before the car become inoperable. When the vehicle came to a stop like at a light the engine would sound like it was going to almost turn off like a rattle noise and a popping sound or like I hit a plastic bag sound on acceleration. Then the day it broke down I was merging onto interstate 15 I heard the same popping sound, the engine light came on and my car broke down. My car was towed to Mercedes Benz of Ontario and inspected by technicians there and by the claims inspector for safe guard international (service protection plan i purchased with the vehicle)I was told it needed an entire new engine due to cracks in two pistons, etc. This was confirmed by the claims inspector with safe guard. This car was well maintained and only had 69,000 miles on it. I don’t think I need to explain the how my safety or the safety of others was at risk when my car breaks down in the middle lane on interstate 15 in California and I have to get over to the shoulder. This vehicle is available for inspection if needed.

NHTSA ODI 11498619

Aug 27, 2022

I have a 2018 C class. Purchased it with 32k mikes 12/21. April 2022 I started experiencing issues. When I put my car in drive/reverse the gears shift it’s self back to neutral. When I’m stopped at a light it will take me out of drive and shift it’s self in neutral. I’ve taken my car to the Mercedes dealer for a diagnostics paid out of pocket and they were unable to find the issue. This is a major safety concern and I would like to be contacted as it is unsafe to drive and no one seems to be able to locate the issue so it can be repaired.

NHTSA ODI 11481491

Aug 16, 2022Engine

Engine light appears due to P052e code “positive crankcase ventilation regulatory valve”. Part failed prematurely and appears to be a common problem in make/model. May cause engine damage due to inability to clear combustion gases in the crankcase.

NHTSA ODI 11479681

Aug 9, 2022Engine

CRACKED PISTON AT 68K MILES The vehicle is very well maintained, only 68k miles, has had every oil change, only takes premium gas. I was driving it when the check engine light went on and the vehicle began shaking violently. After towing the vehicle to the Mercedes Benz dealership, they informed me that the piston cracked and they could not articulate a reason why this would happen.

NHTSA ODI 11478301

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Working with the data? Download all 125 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 2018 Mercedes-benz C-class Hybrid verdict →