NHTSA Owner Complaint Log
This page lists owner-reported complaints filed with NHTSA for the 2017 Mercedes-Benz C-Class. Complaints are unverified consumer reports submitted to NHTSA and do not by themselves prove a defect or defect rate.
Data synced from NHTSA on May 4, 2026
Positive Crankcase Ventilation (PCV) Can cause problem to the engine. Check engine light is on, car have been scanned. This happen one week ago. There’s no recall for this and happen a lot many Mercedes Benz causing problems on engine and is not on warranty or any other recalls
I have a mercedes c300 2017 and recently I was driving my car and the check engine light came on all of a sudden so I took it to my local shop to diagnose it they told me it was the PCV valve, so I called mercedes and they’re telling me that this is not covered and of course my warranty is no longer covered I have about 63k miles on the car. Mercedes is saying they don’t have a recall for this but I’ve googled around and multiple people are saying the same issue happened to them around the 55-65k range. It’s super frustrating that this doesn’t flag a recall.
The contact owns a 2017 Mercedes-Benz C300. The contact stated that while driving at approximately 75 MPH, a loud popping noise was heard and then the sunroof exploded. The contact stated that there were no injuries sustained from the glass shards that had fallen inside the vehicle. No warning lights were illuminated. The vehicle was not yet taken to an independent mechanic or local dealer to be diagnosed repaired. The manufacturer was made aware of the failure and advised the contact to file a complaint with the NHTSA Hotline. The approximate failure mileage was 15,000.
P502e code crankcase ventilation failure
My preowned vehicle has a strong gas odor in the cabin while operating. I don’t see any safety recalls but I did read online that a class action lawsuit proved my model may have faulty fuel parts causing seepage and the watranty is extended to 10yr/120k miles. I have scheduled maintenance this week but would like to be certain the warranty will cover this. Thank you.
Repeated Panoramic Sunroof failure: sun roof rails are have been reported by the dealer to fail / crack and allow panoramic sun roof to dislodge from tracks securing this structure to the vehicle. NOTE THIS IS NOT RELATED TO/ADDRESSED BY THE PREVIOUS RECALL Loud cracking noises heard and the sunroof stuck in an open position and appeared at risk of departing the vehicle on initial occurrence 2019/2020 Dealer attempts to repair resulted in replacement of the rails which are reportedly "made of plastic and do not hold up well in southwestern US temperatures/climate" Repairs/rigging the system appears to "load the rails" and dealer reported life limits can be as low as 10 cycles / 30 months This issue has occurred three times in the past 4 years 92k miles Improper closure/ cracked tracks could result in incomplete cabin security during a roll over and/or potential for the panoramic sunroof to depart the vehicle to become a threat to other traffic.
Engine code P052E - PCV REGULATOR VALVE PERFORMANCE. Common faulty Mercedes Benz part integral to the car. Just took in the car to MBSeattle.
In my family we have 2 mercedes benz cars one 2017GLC300 and other 2017 C300 4matic and both of the cars have the same issues. Check engine with code P052E. And after talking to friends and mechanics it appears that this issues to be almost on every mercedes car of this engine since both of the cars that are in my family have the same engine components. I request that it should be recall so mercedes benz will repair those issues under warranty. Thank you
Front safety system inoperable
I was driving on highway I95, all the sudden, the vehicle shows, Power Steering Malfunctioning See Owner's Manual. I've lost the power steering in the middle of the highway. The steering was so hard and not safe. The next day, I've started the car and the issue isn't there anymore! Now the car is driving fine!!! Please, this need to be fixed, cause it may happen again, and that happens on a sharp curve, it may lead to a crash!
My car suddenly turned off at a stop sign. After I restarted it, it turned back on and my engine light turned on. I called the dealership and after inspection I was told that the valve for my crankcase was malfunctioning. The total cost, including both parts and labor are $1775. I have seen many complaints regarding this issue with the same vehicle. It is apparent that a recall should’ve been issued for this months ago. It is truly a safety issue when the car turns off at a stop sign or a ramp. I could’ve been hit while my car was stalling on a ramp exiting major highway. I implore you to rectify this issue immediately before someone gets hurt.
Crank case ventilation valve causing check engine lamp. Car has 42k miles. Recommended repair cost $2000
I purchased my 2017 C300 class Mercedes-Benz ("MB") in May 2021 from a used car dealership in Mobile, AL. At that time it had 36,000 miles. Less than 2 years later, on or about 12/15/22, as I was driving, the MB suddenly and without warning began to vibrate violently and immediately lost power. The car had @54,000 miles on it. I routinely drive interstate to and from work and had just gotten off of the interstate. I was lucky that I was driving at a low speed when this happened; otherwise, a serious accident could have resulted. I took it to the local MB dealership which told me that the car failed a compression test in the #1 cylinder and that the engine would have to be replaced. Subsequent research on the cause of this total engine failure with low mileage revealed that this engine has a chronic piston defect that damages the #1 cylinder, causing it to lose compression, and that MB has known about the defect for many years, an issued an internal bulletin about it. MB has not alerted the public nor instigated a recall. I was not informed by MB at any time that the C300 class engine had a chronic piston defect that would damage the #1 cylinder which would, in turn, cause the engine to lose power and the vehicle to vibrate and shake, creating a dangerous diving condition under all circumstances, but especially if the car was being driven at speed on a federal interstate highway. Despite demands by me and others, MB refuses to responsibly address the issue. The driving public is, and remains, clearly, in great risk of harm due to this defective engine and associated power train issues. It is patently unreasonable for MB to produce and market such a unsafe, dangerous and defective product that poses an unreasonable risk of harm to its customers and others when being used as it was intended. I understand that the NHTSA has opened an investigation on this defect and wish for my voice to be heard on it. Please contact me [XXX] for further details. INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).
Most M274 engines have P06DA00 fault code internally. Harness for oil pressure regulating solenoid valve is short/open inside the engine oil pan. It can cause excessive oil pressure and premature oil pump failure. As the broken wire is sunken in the engine oil, I worry if it can cause fire. If the oil pump fair during driving prematurely, engine can be stalled. Mercedes-Benz knew the issue but they decided to ignore it.
Hey good morning. There’s been a been a system failure. P052E Positive Crankcase Ventilation Regulator Valve Performance. Warning message I got was the engine light showed
Crankcase ventilation valve failure.
ode P052E : Positive Crankcase Ventilation Regulator Valve Performance. This seems to be a common problem with the C300.It's not an easy fix. MB hasn't addressed this common issue. Also strong smell of gas coming into the cabin during start up. Took car to Keys Van Nuys Mercedes in North Hollywood and was no recall. We are inhaling these fumes and they blamed it on a hose that expands and fumes escape into the cabin. Wanted to charge for the repair but I refused.
Crankcase Breather System: Vent Valve Fault code stored for block crankcase breather valve. The fault code is 052E71. A lot of Mercedes cars are reporting it online and no recall has been made. The labor to change this takes around 8-9 hours and the part costs 300. Company is doing nothing about it as a lot of W205 engines are having this issue
The contact owns 2017 Mercedes-Benz C300. The contact stated while driving 45 MPH, he heard air coming in through the OSI cover. Once the contact arrived at his destination, he noticed that the front sunroof panel had detached from the vehicle. The dealer was contacted and stated that the vehicle was not under warranty and that the vehicle was already repaired under NHTSA Campaign Number: 21V197000 (Structure). The manufacturer was contacted and stated that the vehicle was not under warranty and that the dealer was not obligated to repair the vehicle free of changer. The failure mileage was 40,000.
Engine bay gets too much water whenever car wash has been done due to space between windshield and plastic engine bay shield (right hand side from vehicle driver seat) has slight gap.
When I started my car, the dash did not reveal park, drive, or reverse. It illuminated with a warning light indicating an Electronic Stability Problem (ESP). Research revealed this to be an important safety feature and that the Mercedes-warning-lights-electric-stability-control may have problems with traction control requiring attention. The ESP light was NOT flashing for the system to intervene – as the car was parked in my garage. It did not light up with the word ‘OFF’ to assess whether it may have been inadvertently deactivated. The light stayed on indicating a suddenly improperly working ESP system. The light remained on after stopping and restarting the engine several times as the dealer maintenance technician suggested concluding with my vehicle being towed to Mercedes Benz of Augusta for service. I am not sure if the MB mechanic reproduced the issue as they discussed several other potential failure points before resolving to replace an item in the steering control module. Experiencing this alert, I became more concerned that a safety inspection may not have been part of the last maintenance service. This is my third Mercedes and I make sure to keep up with all my maintenance. I had never seen this warning light before. Up until this time the only warning light I had seen in my car was for low air in my tires. My safety was not at immediate risk. I am glad my car was not able to be driven, as I would have hated for it to stop while I was out and about. I am a proud Mercedes Benz owner as they are world renown for the safest cars on the road. My car has just over 25,000 miles and it was unimaginable that it would have this kind of failure. I should not be held accountable to pay for a safety failure that I should be part of required maintenance checks. An additional periodic Mercedes required safety inspection could prevent this potential breakdown while providing another measure to protect the life of Mercedes Benz owners.
Check engine light. Code: P052E, positive crankcase ventilation regulation performance.
Piston one issue. I bought this car from an auction and according to the record on the car the previous owner had problem with piston one and low compression in that piston. After performing some research it looks like Mercedes’ Benz c300 m274 is riddles with this issue. It’s all over the internet and I don’t know why Mercedes is not taking responsibity for this. This car has less than 70000 miles and the engine is locked from the cylinder. Thank you
The contact owns a 2017 Mercedes-Benz C300. The contact stated while driving 45-50 MPH, the vehicle stalled inadvertently and would not exceed 3 MPH. There was no warning light illuminated. The contact was unable to veer to the side of the roadway. The contact turned on the hazard lights. The contact turned off and restarted the vehicle however, the vehicle would not exceed 5 MPH and was making abnormal sounds. The contact veered to the side of the road for approximately 4 hours until there was no longer traffic on the roadway. The contact proceeded to drive at 5 MPH to her residence less than two miles away. The manufacturer was notified of the failure and assisted with towing the vehicle to the dealer to be diagnosed. The contact was informed that the piston rings had blown out and the engine needed to be replaced. The manufacturer informed the contact that the failure was a known failure; however, she would be responsible of the cost of the repair. The vehicle was not repaired. The failure mileage was approximately 29,650.
My car threw the check engine code P052E, the issue is the positive crankcase ventilation valve being faulty. Incredibly common on this model and now failed on my car too at 60K miles. All maintenance was done up to this point with the dealer and at or before recommended intervals.
The contact owns a 2017 Mercedes-Benz C300. The contact stated that she heard air entering the sunroof however, while attempting to close the sunroof, the sunroof failed to close as designed. There was no warning light illuminated. The vehicle was taken to the dealer however, the contact was unsure of the diagnostic result. The vehicle was not repaired. The manufacturer was notified of the failure and the contact was informed of a program that was cost effective. The contact was referred to the NHTSA Hotline. The failure mileage was approximately 56,000.
My car leaked oil very fast while me & my wife were on a trip and it stopped on the highway and engine was stalling and misfiring due to a manufacture defect that is common with this model so it did put us in a very dangerous & risky situation. Now after i paid $1,740 the dealer is saying that my car needs a new engine due to cracked piston in cylinder 1 that damaged the engine which is a common problem with this model around the 50k miles.
The contact owns a 2017 Mercedes-Benz C300. The contact stated that while driving 65 MPH on the highway, the contact heard a popping sound coming from an unknown part of the vehicle. The contact pulled over to the side of the road, exited the vehicle, and became aware that the roof panel had shuddered. The contact stated there was no glass in the vehicle. No injuries were sustained. The contact stated that the failure had occurred on two occasions. The vehicle was not taken to an independent mechanic or the dealer to be diagnosed. The vehicle was taken to the dealer by the previous owner to be repaired under NHTSA Campaign Number: 21V197000 (STRUCTURE); however, the recall repair failed to prevent the failure. The manufacturer was notified of the failure and informed the contact that there was no recall related to the failure. The manufacturer offered the contact a trade for the vehicle. The failure mileage was 105,000.
My check engine light keeps jumping off and on, went to get diagnosed and the PCV valve came back. I’m not sure why
The contact owns a 2017 Mercedes Benz C300. The contact stated while driving at a slow speed in traffic, another vehicle rear-ended and caused her to crash into the vehicle in front. The air bags did not deploy. The contact sustained injuries to the back of her head, her left shoulder, right wrist, and right arm along with chest pains and facial contusion. The contact sought medical attention at an emergency room. A police report was filed. The vehicle was not drivable. The contact towed the vehicle to her residence. The vehicle was not diagnosed or repaired. A dealer was not contacted. The manufacturer had not been informed of the failure. The failure mileage was approximately 57,000.
Check engine light came on, took it to the dealership. It is the Crankcase Ventilation Valve that is once again broken. It helps to accurately depict emissions. It is a known problem that hundreds of other drivers are reporting on forums https://www.benzworld.org/threads/2015-c300-crankcase-ventilation-valve-replacement-p052e71.3047538/page-1 https://mbworld.org/forums/c-class-w205/739851-check-engine-code-p052e.html There needs to be a recall, this is a consumer protection and environmental safety issue.
I was reversing my vehicle when I heard a snap, and the inside dash panel warning sign came on…later I google it and found out it has happened to many other people. the clock spring behind the steering wheel snapped and airbags warning signs came on with possibility of deploying at any moment.
misfire cylinder 1 46300 miles on the engine.Mercedes dealer told me I need new engine and they are not providing warranty coverage.
There is an existing recall (21V197000) from Mercedes regarding defective glue attaching the roof panel to the car. The roof panel can dislodge and fly off the car, creating a road hazard. I have the same issue on my 2017 C300 where the panel has moved, causing a whistling noise. The deal has diagnosed this issue. However, my VIN is not covered by the Mercedes recall. I have reached out to Mercedes, and they refuse to include my vehicle in the recall. Other 2017 C300 models are included. I believe their recall does not cover all affected vehicles. The recall number is 21V197000.
P06DA00 CODE oil pump vale circuit open
CODE PO052E71 crankcase vent solenoid causing check engine light
The contact owns a 2017 Mercedes-Benz C43 AMG. The vehicle had previously been serviced under NHTSA Campaign Number: 21V197000 (Structure). The contact stated while driving 60 MPH, the sunroof glass was rattling. The contact pulled off the exit to check the sunroof. The vehicle was not diagnosed nor repaired by an independent mechanic or dealer. The manufacturer was made aware of the failure, and the contact was awaiting a callback. The failure mileage was approximately 85,000.
Diagnosis code P052E PCV regulator valve replacement/crankcase replacement. Dealership does not want to acknowledge code while car was under warranty despite proof that it existed when check engine was diagnosed. Now 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. I urge you to investigate this matter with other clients and ask the manufacturer to replace part and pay for labor.
At approximately 26,500 miles of use, the check engine light came on in my Mercedes Benz C300. I brought the vehicle to the dealership and they informed me that the diagnosis was a crankcase vent valve malfunction. The MB fault code is P52E71. After paying Mercedes to fix the issue, I found forums on the internet where many other MB owners reported the same issue at around the same mileage. Being that this seems to be a common malfunction with the C300, I believe that it should be considered as a recall issue. I don't know what could have happened if I didn't service the vehicle, but any engine issue is dangerous while a vehicle is in motion.
Please see attached letter: [XXX] Mercedes Benz Crankcase Valve Claim.pdf, repair estimate and other correspondence from Mercedes-Benz. This is an well-known issue where there is a gas lead from the engine where Mercedes insists doesn't pose a safety issue. During cold starts there is a smell of gas in the cabin and this is prevalent in colder climates like New England. Mercedes should make cars for all markets that are safe. INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).
Issue: Front driver and passenger seat belts do not fully retract despite completed recall service. The seatbelts often "puddle" behind the seats when unbuckled, and sometimes get trapped between their seat and adjacent door. My car was recalled and serviced under Mercedes Campaign 2021020010 to fix this in October 2021. Also, the right front seatbelt was replaced in October, 2018 under Campaign 2017050023. The first paragraph of the Mercedes Recall Campaign Bulletin states, "...certain C-Class Cabriolet vehicles (A205 platform) with PRE-SAFE might not meet the requirements of FMVSS 208, S7.4.5., as the front seat belts might not fully retract to its stowed position. In this case, certain regulatory requirements under FMVSS 208 might not be fulfilled. If the seatbelt webbing does not fully retract into its stowed position, the consumer may find the operation of the seatbelt inconvenient and not wear it, increasing the risk of injury in the event of a crash." In its step 1, the bulletin states, "The seat belt strap must retract into its final position automatically. Provide manual assistance with rolling up the seat belt strap if necessary." Having to provide manual assistance to retract the seat belt does not meet the definition of "must retract into its final position automatically". Further, it does not meet the aim stated in the bulletin's first paragraph about the importance of the seat belt fully retracting. The labor time spent on campaign was only 0.10 hours (6 minutes), so nothing more than a cursory inspection was done, and not any actual service work. I spoke with my local Mercedes dealer and the Mercedes USA customer service rep. They are both Ok with manually feeding the seatbelt into its slot. This is unacceptable and does not meet FMVSS 208. Both the dealer and the Mercedes USA say I can pursue proper fix at my expense. This is a failed recall service and I should not have to pay to explore a proper remedy.
Sunroof Front Trim for Mercedes-Benz GLC300 IS ALL SCRATCHED BUT MERCEDES BENZ SAYS IT IS NOT COVERED BY THEM.
I’m trying to ship my car back to the United States and there is a valid recall on my car which I have taken it to the dealership in Korea, which is where I’m currently at, and I cannot get me car updated either because they don’t understand the paper or because I don’t have an official recall which I have also encountered in the states. Without this update my car will not be shipped back home with me. Is there any way I can get this recall information in Korean to possibly make them perform the update.
Check engine light code " P052E71" Crankcase Ventilation Valve Replacement is needed. There is a defective part oil separator and the valve is stuck. Must replace the whole assembly with the hoses. (Part is available for inspection). The problem has been confirmed by the Mercedes dealership. When starting the car, gas fumes come out and is very distinct in the air which is VERY dangerous in confined spaces as well as around other people. . You will fail emissions testing due to this. The repair will cost between $1600 - $2000. This is a know defect in these cars and should be recalled. It also pollutes the air and put the safety of everyone around in danger.
When starting the car in the morning there is fuel smell that gets into the cabin. Additionally, as the car is idle during the drive, the smell of fuel is very obvious. Windows have to be rolled down to avoid the smell
The contact owns a 2017 Mercedes-Benz C300. The contact stated that the seat belt latch plate failed to latch securely into the buckle of the seat belt while the contact was attempting to exit the vehicle. The contact referenced NHTSA Campaign Number: 21V032000 (Seat Belts). The vehicle was taken to the dealer to be diagnosed. The contact was informed that the latch needed to be replaced. The seat belt was repaired but failed to operate as needed. The manufacturer was notified of the failure. The failure mileage was 22,000.
Strong gas smell when car is idling and miles to empty goes down very quickly, approximately a mile or more a minute. There is no recall for this problem and Mercedes is very aware of this problem.
Strong gas odor in the cabin and in motion to the point of causing me to be light headed with my children in the car. Smell of gas coming from the engine when parked. No lights or warnings and it does not occur all of the time just sometimes however ive noticed it 3x the last 5x i have drove my car, the cabin was only extremely bad once.
The car was parked on my driveway, As soon as i started it, I got a message 'The electronic rear axle differential lock is inoperative' NHTSA previously issued a recall for 2017 C63s AMG models. I purchased this vehicle from Carvana in April 2021 with clean single owner carfax. The manufacture warranty has expired. I have seen lots of posts on Mercedes forum talking about this issue where Mercedes did fix the issue free of cost. Since there is no open recall on my vehicle, I am not sure what to do.
MB USA extended the warranty coverage on the low pressure fuel hoses that connects to the high pressure fuel pump. The reason is "under certain cold ambient conditions during a cold start of the engine, the low pressure fuel hose at that connection may experience slight fuel weeping". MB USA, however, ruled out a safety risk. NHTSA needs to investigate it. If MB USA found the fuel pressure line is defective, they needed to do a recall. I believe it must be a recall as fuel leaks is not only a safety risk but also a serious health hazard to the occupants. What if the occupants have sinusitis and don't smell well. What if the leaks is too small to smell enough but can still be a health issue.