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2017 Mercedes-Benz C 300 Engine Problems

Owner-reported complaints naming the engine system, filed with NHTSA

Data refreshed

Engine reportsComplaints are reports submitted to NHTSA by owners and drivers. NHTSA does not verify most reports before publishing them, and a complaint does not establish that a defect exists. Volume is influenced by how many of a vehicle were sold, how long it has been on the road, and how much attention an issue has received.
79
Latest Jul 27, 2026
Share of all reportsThis category as a share of every owner report on file for this model year. One report can name more than one component, so the categories overlap.
37%
of 215 total
Crash or fire reportedReports in this category whose submitter recorded that a crash or a fire occurred. The reporter's own answer on the NHTSA form, not a verified finding.
1
Injuries or deaths reportedTotals the submitters entered on their own reports in this category. Not verified by NHTSA and not a casualty statistic.
0

What this page shows

Reports naming the engine itself — including stalling, misfires, oil consumption, cooling and internal engine components. Every record below is an owner-reported complaint about the 2017 Mercedes-Benz C 300 submitted to NHTSA — not a confirmed defect, not a recall and not a manufacturer bulletin. 79 reports on file name it.

Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.

Owner reports naming engine

The 25 most recent of 79, in the owner's own words

Engine
Filed Jul 27, 2026

2017 Mercedes c300 the switchover valve in the diagnostic module of the evaporative emission control system is jammed open. This issue was called for recall for models 2018 or later, but 2017 was not part of it.

NHTSA ID
11753176
Incident
Jul 27, 2026
ElectricalEngineFuel system
Filed May 15, 2026
Fire reported

The contact owns a 2017 Mercedes-Benz C300. While driving at approximately 15 mph, the contact observed smoke emanating from under the hood. The vehicle was driven to her work location and parked. Upon exiting the vehicle and opening the hood, she observed orange flames coming from the engine compartment. A parking attendant extinguished the fire, and a police and/or fire report was filed. The vehicle was towed to a dealer and diagnosed with a fuel line leak that caused the engine harness to come apart. The leaking fuel hose from the high-pressure fuel pump caused damage to the high-pressure pump, engine harness, vacuum transducer, and coolant feed line from the thermostat to the firewall. The following components needed replacement: high-pressure fuel pump, rubber fuel hose, engine harness, pressure transducer, and intake manifold. The vehicle was repaired. Five months later, the contact experienced another failure she believes was associated with the engine fire. While parked and attempting to start the vehicle, it did not start. The vehicle was towed to a dealer and diagnosed with a faulty starter that needed replacement. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 65,422.

NHTSA ID
11738037
Incident
Oct 29, 2025
Mileage
65,422 mi
Engine
Filed Mar 20, 2026

Check engine light for P052E which has been coming and going off for years now. Now the check engine light is there permanently. I spoke to Mercedes Benz customer service and requested for them to fix the problem now that the light is on permanently but they refuse to fix it because the car has 222,000 miles on it. This should be a recall from the manufacturer not an extended warranty coverage. The Mercedes dealer in Valencia California told me they now only do a software update and put a plug cap on the sensor and want to charge me $850 even though this should be a recall

NHTSA ID
11725960
Incident
Mar 20, 2026
Body & structureElectricalEngine
Filed Oct 30, 2025

I am reporting a serious vehicle safety hazard caused by improper and unsafe repair work performed by USA Platinum Motor, located at 1221 California Lane #126B, Arlington, TX. I brought my 2017 Mercedes-Benz C300 in for a cold start rattle with no warning lights or prior issues. The shop diagnosed a loose timing chain and I authorized the repair. After the repairs, the vehicle was returned with critical safety defects, including a loose fuel pump, unsecured fuel line, missing bolts, and improperly reassembled engine components. Shortly after pickup, the car experienced loss of acceleration on the interstate, a strong odor of fuel, and a sudden loss of power, creating a dangerous and life-threatening situation. The vehicle had to be towed back to the shop. The manager, who is not a certified mechanic, admitted he personally “fixed” the issue by tightening the fuel pump himself. A Mercedes-Benz diagnostic inspection later confirmed multiple severe assembly errors, including missing fasteners, unsecured oil cooler, disconnected vent lines, and other safety-related defects in the fuel and cooling systems. These unsafe and negligent repairs created an extreme fire hazard, engine instability, and risk of sudden failure while driving. I am requesting a formal NHTSA investigation into this matter to ensure vehicle safety compliance and to prevent similar incidents affecting other consumers.

NHTSA ID
11696497
Incident
Oct 24, 2025
ElectricalEngine
Filed Apr 13, 2025

ESP control unit software Recall 2016090002 Recall 2017110002 Recall 2020080016 And my car shows there’s cero recall active but is giving me problem showing code: U0121 u1110 U0122 B227d U0423 B227d

NHTSA ID
11654348
Incident
Mar 5, 2025
Engine
Filed Feb 16, 2025

this is my send time writing in. mercedes used the wrong wrist pins for the pistons leading to my wife getting a cracked piston on freeway in phx.if you look up cylinder 1 issues on this model there is a lot of people who have encountered this. why this hasn't been recalled and sticking consumers with a10k plus repair is beyond me. if you use the wrong parts you should be responsible for the repair!!!

NHTSA ID
11643047
Incident
May 2, 2024
Engine
Filed Oct 31, 2024

I have an error code: P052E.

NHTSA ID
11623039
Incident
Oct 31, 2024
EngineFuel system
Filed Oct 21, 2024

my whole entire car smells like gas. I cannot drive this car around because I will pass out and it is a safety hazard. There is a recall for this exact same issue, just not for my Vin number. I would like to get this done for my car, please.

NHTSA ID
11621009
Incident
Oct 19, 2024
EngineFuel system
Filed Aug 20, 2024

Keep getting a code P052E! Changed the oil and code went away for a few days then came back. Looked into getting it fixed and it seems like Mercedes has known about this issue and hasn’t called for a recall on this piece of equipment! Very costly to fix and says it needs to be replaced every 30k to 50k miles! At around 1k to 3k to fix everytime that’s something they should recall

NHTSA ID
11609586
Incident
Aug 14, 2024
Engine
Filed Aug 11, 2024

P052E code for PCV vent valve

NHTSA ID
11607831
Incident
Aug 11, 2024
Engine
Filed Aug 10, 2024

cracked piston in cylinder #1. After doing research this is a common problem in the m274 engine from 2015-2018 which Mercedes is aware of but does nothing. mercedes need to be held responsible and a recall issued. This isn't a 2 or 3 thousand dollar repair!! this repair is 6 figures!!! Please hold them acountable!!! THX

NHTSA ID
11607748
Incident
May 2, 2024
Engine
Filed Jul 22, 2024

Check engine light on. Test results: Positive Crankcase Ventilation Regulator Valve Performance CODE : P052E

NHTSA ID
11603672
Incident
Jul 20, 2024
EnginePowertrain (other)
Filed Jul 10, 2024

Car check engine light came on with only 62,000 miles. Diagnosed as code P052E, the issue is the positive crankcase ventilation valve being faulty. Regular oil changes and maintenance was done. I see multiple complaints with this issue, why is this not recalled? It is very expensive to have fixed.

NHTSA ID
11601009
Incident
Sep 29, 2023
Engine
Filed Jul 2, 2024

My engine light keeps coming on and off on my 2017 C300 4matic coupe. I got the problem diagnosed in March 2023. Benz said I had a faulty solenoid valve and that I would need to replace the crank case ventilation assembly. That is $3000. My friend has a C300 sedan and they replaced his under the extended warranty that came out on August 2023 for the crankcase. I have the same exact issue but they said my VIN doesn’t populate so they cannot do anything. This is the 2nd faulty crank case in my car, it was replaced by warranty in 2019. I don’t drive that much I have 47K miles on the car. They refuse to cover the faulty part.

NHTSA ID
11598324
Incident
Mar 16, 2023
Engine
Filed May 8, 2024

po52e71 the valve for crankcase ventilation has malfunction

NHTSA ID
11587623
Incident
May 1, 2024
Engine
Filed Apr 12, 2024

P052e positive crankcase ventilation regularly valve

NHTSA ID
11582711
Incident
Apr 7, 2024
Engine
Filed Mar 29, 2024

Check engine light on on 2017 Mercedes C300 4 Matic. Car has 52,000 miles on it. The code P052E71 was diagnosed by Mercedes mechanic as the valve for the crankcase ventilation. The actuator was blocked. Mechanic said part (crankcase ventilation hose) is not available and this problem happens to all 2015-2017 C 300 models usually around 50,000 miles. When air conditioning or heat is run it causes an odor of burning fuel or oil in the cabin. Mercedes said part is not in stock and they have no ETA on when it will be available. Vehicle is unable to pass vehicle emissions test.

NHTSA ID
11580115
Incident
Feb 26, 2024
EnginePowertrain (other)
Filed Mar 29, 2024

The contact owns a 2017 Mercedes-Benz C300. The contact stated that while at a stop light the vehicle stalled. There were no warning lights illuminated. The vehicle was taken to the local dealer where it was diagnosed and determined that the battery cable needed to be replaced. The vehicle was repaired but the failure recurred. The vehicle was taken back to the local dealer where it was diagnosed that an update to the powertrain software was needed, and the transmission pump needed to be replaced. The vehicle was repaired but the failure persisted. The contact called the local dealer, and it was recommended that the transmission be replaced. The vehicle was not repaired. The manufacturer was contacted. The failure mileage was approximately 80,000.

NHTSA ID
11580064
Incident
Feb 1, 2024
Mileage
80,000 mi
Engine
Filed Mar 18, 2024

My Mercedes benz C300 2017 have the P052E positive crankcase ventilation regulatory valve, and Mercedes Benz they start sending this letter and when I go to the dealer they said my car not qualified, but the letter says other thing, my car have the check engine light on with the code PO52E. They don’t want to do the repair because is a $2,500 repair and they making excuses to not do it.

NHTSA ID
11578049
Incident
Feb 16, 2024
Engine
Filed Mar 17, 2024

P052E Positive Crankcase Ventilation Regulator Valve Performance this is a common issue with Mercedes as lots of car are affected by this and this should be covered under emission but lots of dealership are declining saying it’s not covered under emission warranty but this code cause pollution and this part is so expensive to fix and I paid 2k to fix it last year and that same code came again. We can’t keep paying 2k plus for something Mercedes fault design Please help us and make Mercedes Recall this Part

NHTSA ID
11577903
Incident
Mar 8, 2024
Engine
Filed Mar 10, 2024

P052e..PVC ventilation crank shaft valve sensor, too many people all reporting the same expensive item/ labor intensive work by a dealership just after the warranty expires. Help. There are thousands of us with the EXACT SAME CODE AND PROBLEM!! ORDER A RECALL INVESTIGATION!! PLEAS?!?!!!

NHTSA ID
11576501
Incident
Dec 5, 2023
EngineSeat belts
Filed Mar 6, 2024

The contact owns a 2017 Mercedes-Benz C300. The contact had received notification of NHTSA Campaign Number: 21V032000 (Seat Belts). The vehicle was taken to a local dealer and the recall repair was performed; however, upon retrieving the vehicle, the check engine warning light illuminated upon starting the vehicle. The vehicle was taken back to the dealer and remained in the dealer possession. The manufacturer was not notified of the failure. The vehicle was not repaired. The failure mileage was approximately 34,000.

NHTSA ID
11575740
Incident
Mar 5, 2024
Mileage
34,000 mi
Engine
Filed Feb 22, 2024

Check engine light came on. Error code indicates a PCV crankcase ventilation valve has malfunctioned. Code is P052E. This is a notorious problem with Mercedes, BMW and other European cars. It should also be considered part of the emissions system. Contacting the MB dealers, I cannot get a clear definition whether it is covered by extended warranties or any warranty whatsoever. They are vague as to "maybe, but not sure". I feel that there should be a recall to fix the defective parts involved with this error code.

NHTSA ID
11573268
Incident
Feb 5, 2024
Engine
Filed Feb 21, 2024

P502e code crankcase ventilation failure

NHTSA ID
11573103
Incident
Feb 15, 2023
Engine
Filed Dec 19, 2023

P052E PCV Regulator Valve Performance

NHTSA ID
11561010
Incident
Dec 15, 2023

Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.

Other components reported on this vehicle

Categories with enough reports to have a page of their own

Elsewhere on this vehicle

Data sources

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