What 73 owners told NHTSA about the 2019 Mercedes-benz C-class Phev

Throttle body and accelerator pedal position sensors failed. Component is available for inspection upon request. Independent service center confirmed failure on 1/3/2026 with 6 stored fault codes: P2101, P0122, P0222, P0123, P0223, P2135. Vehicle shuts off while driving without warning at various speeds. Loss of power steering and power brakes occurs when engine stalls, creating immediate risk of crash, injury or death to occupants and other drivers. Manufacturer customer service confirmed in writing 4 times that engine shutting off while driving is a safety issue and that these exact codes match Service Campaign 2022090005. On 1/7/2026, manufacturer denied campaign applies to this vehicle and refused no-charge dealer inspection, demanding customer pay diagnostic fees to confirm defect they already documented. Vehicle has not been inspected by manufacturer or dealer because manufacturer refuses free inspection. Check engine light illuminated prior to stall events. Manufacturer has actual knowledge of safety defect under 49 U.S.C. 30118 and is creating financial barrier to repair of defect covered by their own service campaign. Request NHTSA investigation and order manufacturer to repair under Service Campaign 2022090005 at no charge.

NHTSA ODI 11747712

Upon starting engine while parked the engine vibrated roughly then stopped. Engine light and coolant light illuminated but shut off. Vehicle proceeded as normal, however, as I proceeded for the highway about 1 - 1/2 blocks and approximately 1,200 feet before approaching highway the vehicle 1200 abruptly lost acceleration; engine light and coolant light illuminated again, then engine abruptly shut down in the middle of the road causing a severe safety hazard. Putting myself and others at risk. There were no symptoms of the problems prior to the failure. Coolant leakage; sluggish engine/acceleration; jerking acceleration; coolant light illumination steady.

NHTSA ODI 11738906

While driving on highway, the engine light came on, a diagnostic test was performed by dealer, oil control valve defected) This could cause engine to lock up while driving, a serious safety concern. I contacted Mercedes Benz corporate office seeking help, because of factory defect. They're not assisting me with this extreme safety matter!!

NHTSA ODI 11712677

While driving at approximately 65 mph on the I-405 freeway in Irvine, CA during rainy conditions, my 2019 Mercedes-Benz C300 suddenly and completely lost acceleration without warning. At the same moment, a Check Engine Light illuminated on the dash. I was forced to coast across all lanes and stop in the emergency shoulder in a very unsafe area with high-speed traffic passing close by in low visibility rainy conditions. Multiple vehicles nearly struck us, including one that had to emergency brake directly behind my car in the shoulder. I contacted AAA and the vehicle had to be towed because it was not safe or driveable. My girlfriend was also in the car and both of us experienced significant fear and distress during and after the incident. My mechanic retrieved fault code P019185 and stated this is a known software problem with the engine control unit that requires a Mercedes software update and reset of mixture adaptations per a manufacturer LI/service document. This means the manufacturer appears aware of the defect and the required software fix, yet I received no recall notice or safety warning. A sudden total loss of engine power at highway speeds creates an extreme crash risk and life-threatening danger to the driver, passengers, and surrounding traffic. There have been other serious drivability issues with this vehicle in the past (misfires, coolant pipe failure, etc.), but this incident was the most dangerous. I am reporting this because this defect appears safety-related and could easily cause a fatality if it happens to someone else at freeway speeds. Diagnostic Note from official Mercedes-Benz Fletcher Jones of Newport Beach Mechanic: “FAULT CODE P019185, WILL START WITH PERFORMING THE SOFTWARE UPDATE OF ME CONTROL UNIT, RESET THE MIXTURE ADAPTIONS PER LI DOCUMENT AND RECHECK.” Tow Provider: AAA — tow confirmation available if needed.

NHTSA ODI 11708992

This vehicle was brought to an authorized Mercedes-Benz dealership for regularly scheduled maintenance. Shortly after this service, the vehicle began experiencing significant issues including difficulty accelerating, engine hesitation while driving, and noticeable shaking at idle. This car has never overheated. The vehicle was returned to the dealership for inspection. The dealership diagnosed a cracked cylinder head and advised that the repair requires replacement of the cylinder head at an estimated cost of approximately $11,000. The failed component is available for inspection and the vehicle is currently at the dealership. The vehicle has approximately 46,000 miles, has been regularly maintained, garaged, and driven under normal conditions. These symptoms created engine performance issues that could result in loss of power or inability to accelerate while driving, creating a potential safety risk, especially in traffic or at highway speeds. I regularly transport my young grandchild in this vehicle. The possibility of sudden engine failure, loss of power, or breakdown while driving raises significant safety concerns for myself and any passengers, particularly a young child. The failure has been confirmed by an authorized Mercedes-Benz service center. During my own research, I discovered there have been recalls involving similar engines for the same model year, as well as multiple owner complaints reporting similar engine or cylinder head failures on this vehicle. I contacted Mercedes-Benz customer care on December 17, 2025, after receiving the dealership diagnosis, and was advised that I would receive a response within 72 hours. As of today, I have not received any response. I attempted to call customer care again, but the phone system would not accept a voicemail and no representative answered. My case number with Mercedes-Benz is 19653254. No prior abuse, misuse, or abnormal driving conditions occurred. The vehicle was properly maintained.

NHTSA ODI 11706568

I am writing to formally report an ongoing issue and safety concern with my vehicle. Since the day I purchased the car, I have experienced numerous mechanical problems and have spent a significant amount of money on repairs. In August, I had to take my vehicle to a local repair shop three times due to persistent issues. The car was also towed by AAA three separate times for safety reasons. My main concern is that the vehicle hesitates during acceleration and feels sluggish while driving, which creates a serious safety risk on the road. I contacted Mercedes-Benz and filed a claim regarding this issue; however, I have not received any meaningful assistance or resolution. I am requesting that this matter be re-evaluated and properly addressed as soon as possible, as my safety and the reliability of the vehicle are at risk. Please confirm receipt of this message and advise me on the next steps or any documentation needed to proceed with my claim. Thank you for your prompt attention to this matter. [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11691362

I had a A1 service completed on 5.23.25 with Mercedes Benz dealership in Sourh San Francisco. 2233 Gellert Blvd. On [XXX] 48 hrs later as I was leaving working- 4-5 blocks before entering the freeway, my car suddenly struggled to drive over 20MPH and the check engine light came on. I pulled over a block before entering freeway. I had it towed and got a Lyft’ ride home. It was a holiday weekend and I had to rent a car . Vehicle accessed 2 days later . I was told it needed a software update and there was a bulletin that came out in 2024 recommending to have the update and I needed to pay to have it repaired by performing a hard/soft upgrade . No empathy was evident . I said I knew nothing about it - dealership said they weren’t obligated to advise. I could have been in a collision or caused and accident and seriously injured had it occured while on freeway . This should be a recall as my life was at risk and so are others driving this year, make and model. The Mercedes Rep. told me she tested the car and was surprised by how it struggled to get past 20 mph, she thought maybe the mechanic had made an error a few days before. I feel very lucky I wasn’t in an accident- or a worst seriously injured! This bulletin warning should be a recall and looked into for a future recall that could save life’s. Knowing, this is a risk for a possible accident , it’s unacceptable that it is only a bulletin and not mandatory to share with owners of the this car. This was very scary and stressful situation. I was stuck in an area in Oakland, Ca known for high crime. In the end Mercedes waived the repair fee, they said under the circumstances and how my life was put as risk . I still think perhaps a wire or something may been disconnected- but no one will admit. Hence they waived fee. Please investigate , I look forward to your findings. Respectfully, [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11664002

The contact owns a 2019 Mercedes-Benz C300. The contact stated that while at a stoplight, there was an abnormal odor of fuel inside the vehicle. The contact stated that the vehicle failed to respond as needed. The vehicle was restarted and shut off independently. The check engine warning light was illuminated. The contact stated that the failure was related to NHTSA Campaign Number: 21V961000 (Fuel System, Gasoline). The vehicle was towed to an independent mechanic who determined that the failure was a fuel rail failure. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted and confirmed there were no open recalls on the VIN. The failure mileage was approximately 60,000.

NHTSA ODI 11656739

Po52E71- Emissions issue with crankcase. Mercedes implemented an extended warranty on various models but excluded 2019 C300, which definitely has the same issues. See below in reference to previous models. IMPORTANT EMISSION EXTENDED WARRANTY INFORMATION In our continuing efforts to assure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA, LLC (“MBUSA”) is extending the warranty coverage on the intake line assembly in certain Model Year (“MY”) vehicles listed below from the original New Vehicle Limited Warranty of 4 years/50,000 miles to 15 years/150,000 miles (whichever occurs first) due to the following condition: • Under certain circumstances, the partial-load ventilation valve (a part of the intake line assembly) may not work as intended, resulting in the illumination of the check engine Malfunction Indicator Lamp (‘MIL’). A faulty partial-load ventilation valve might also increase exhaust gas emission. Model Model Years Sales Designation C-Class 2015 – 2018 C 300, C 300 4MATIC C-Class Convertible 2017 – 2018 C 300 Convertible, C 300 4MATIC Convertible C-Class Coupe 2017 – 2018 C 300 Coupe, C 300 4MATIC Coupe C-Class Hybrid 2016 – 2018 C 350e E-Class 2017 – 2019 E 300, E 300 4MATIC GLC 2016 – 2019 GLC 300, GLC 300 4MATIC GLC Coupe 2017 – 2019 GLC 300 4MATIC Coupe GLC Hybrid 2018 – 2020 GLC 350e 4MATIC SLC 2017 – 2020 SLC 300 SLK 2016 SLK 300

NHTSA ODI 11648766

The fuel hose on the right hand side of the vehicle is leaking onto my engine. You can easily see this leak and smell it when unlocking the car in the morning. It is dangerous and could easily result in a fire.

NHTSA ODI 11638548

The contact owns a 2019 Mercedes-Benz C300. The contact stated that the "Service Engine Soon" warning light was illuminated. The contact restarted the vehicle several times; however, the warning light remained illuminated. The vehicle was taken to an independent mechanic who retrieved DTC code: P0600 -which was related to the secondary oil pump. The vehicle was then taken to another dealer where the contact was informed that the vehicle could be repaired at that location; however, the contact was later informed that the dealer did not have the part needed to service the vehicle and referred the contact to another dealer. The vehicle was taken to a dealer where another diagnostic test was performed, and the dealer confirmed the failure. The contact was provided an estimate for the repair but declined the repair. The vehicle was not repaired. The manufacturer was notified of the failure but offered no assistance. The failure mileage was approximately 32,000.

NHTSA ODI 11626838

When depressing the throttle, occasionally there is no response form the engine or a significant delay coupled with erratic engine revving behavior. When this happens the car has no drive power, but power brakes and steering are unaffected. The engine sits at idle speed. This has happened on multiple occasions when in or crossing traffic. The issue may present and then disappear after 15-45 seconds with no other action being taken.

NHTSA ODI 11549824

TL* THE CONTACT OWNS A 2019 MERCEDES-BENZ C300. THE CONTACT STATED WHILE STATIONARY, THE VEHICLE SHUTOFF WITHOUT WARNING. THE CONTACT WAS ABLE TO RESTART THE VEHICLE. THE VEHICLE WAS TAKEN TO THE LOCAL DEALER KEYES EUROPEAN (5400 VAN NUYS BLVD, SHERMAN OAKS, CA 91401 (818) 574-5053) WHERE IT WAS DIAGNOSED WITH NO FAILURES. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS INFORMED OF FAILURE AND INFORMED THE CONTACT TO TAKE THE VEHICLE TO BE REPAIRED. THE FAILURE MILEAGE WAS APPROXIMATELY 4,700. ## VIN PASSED ## MERCEDES-BENZ 2019 C300 ##

NHTSA ODI 11389877

TL* THE CONTACT LEASED A 2019 MERCEDES-BENZ C300. THE CONTACT STATED THAT WHILE DRIVING AT 70 MPH, THE VEHICLE DECELERATED INDEPENDENTLY TO 30 MPH WITH THE CHECK ENGINE WARNING LIGHT ILLUMINATED. THE FAILURE WAS EXPERIENCED THREE TIMES. THE VEHICLE WAS TOWED TO THREE UNKNOWN DEALERS WHERE THE VEHICLE WAS DIAGNOSED AND THE CONTACT WAS INFORMED THAT THE HIGH-PRESSURE FUEL PUMP NEEDED TO BE REPLACED. THE ECM WAS ALSO REPLACED HOWEVER, THE REPAIR FAILED TO FIX THE FAILURE. THE VEHICLE WAS NOT REPAIRED. THE FAILURE MILEAGE WAS 6,000.

NHTSA ODI 11326229

TL* THE CONTACT OWNS A 2019 MERCEDES-BENZ C300. WHILE DRIVING APPROXIMATELY 35 MPH, THE VEHICLE UNEXPECTEDLY SHUT OFF WITHOUT WARNING. THE VEHICLE WAS TOWED TO EURO MOTORCARS BETHESDA (7020 ARLINGTON RD, BETHESDA, MD 20814) FOR DIAGNOSTIC TESTING, BUT THE CAUSE OF THE FAILURE COULD NOT BE DETERMINED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS NOT NOTIFIED OF THE FAILURE. THE FAILURE MILEAGE WAS 1,250. THE VIN WAS UNKNOWN.

NHTSA ODI 11296672

TL* THE CONTACT OWNS A 2019 MERCEDES-BENZ C300W. THE CONTACT PURCHASED THE VEHICLE ON APRIL 6, 2019. ON APRIL 10, 2019 HE TOOK THE VEHICLE BACK TO THE DEALER (MERCEDES-BENZ OF SARASOTA, 4754 CLARK RD, SARASOTA, FL 34233, (941) 275-1293) BECAUSE IT SHOOK VIOLENTLY WHILE DRIVING AND THE ENGINE FELT LIKE IT WAS LOSING POWER AT 20 MPH. ALSO, AN ABNORMAL NOISE WAS HEARD. THE DEALER STATED THAT THE FAILURES WERE NOT ABNORMAL. THE DEALER TEST DROVE THE VEHICLE WITH THE WINDOWS UP AND COULD NOT REPLICATE THE FAILURES; HOWEVER, THEY STATED THAT THE NOISE WAS DUE TO A DESIGN FAULT THAT OCCURRED WHEN THE REAR WINDOWS WERE OPEN. THE CONTACT SPOKE WITH THE STATE ATTORNEY GENERAL'S OFFICE AND WAS ADVISED TO PURSUE HIS CONCERN UNDER THE STATE LEMON LAW. THE CONTACT CALLED THE MANUFACTURER AND WAS INFORMED THAT THE CASE WOULD BE ASSIGNED TO A CASE MANAGER AND HE WOULD BE CALLED BACK WITHIN 24 HOURS. IF THE ISSUE COULD NOT BE RESOLVED, THE CASE WOULD BE TURNED OVER TO AN EXECUTIVE INVESTIGATING SQUAD. THE DEALER CALLED THE CONTACT AND ASKED FOR A CALL BACK. AFTER SEVERAL ATTEMPTS TO CALL THE DEALER, THE CONTACT HAD NOT HEARD BACK. THE FAILURE MILEAGE WAS 1,700. *BF *JB

NHTSA ODI 11220826