2019 MERCEDES-BENZ C 300 Complaints

Shifting gears when stopped and the car lunged forward while I was stopped at a red light. I almost hit the car in front of me at the red light. Very rough gear changes and changing out of the correct gear to the wrong one and then back into another one. Severe speed changes - jerking the car back or it lunges forward, while driving results in loss of reasonable control of the vehicle and inability to to shift correctly out of traffic. Mercedes benz has a technical service bulletin on this problem and is aware that the 9G-Tronic - internally designated as the 725 transmission (fault code P07B700) is defective and known to experience sudden pressure sensor failures or valve body faults within the transmission control unit which prevents the car from shifting gears corrected or forces limp mode. The repair is a minimum of $5,200. MBZ has known this is a defect and wide spread issue but unwilling to contribute to the repair or recall or respond to my letters and the inquiries of other vehicle owners I have spoken to that have the same issues. It is a catastrophic mechanical failure from a sensor they know is bad and is occurring shortly after warranties are expiring. It is putting all of our lives and the lives of others at risk of an accident due to the failure of their part. Thank you for your consideration.

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.

My 2019 Mercedes-Benz C300 Coupe’s front driver seat belt will not fully retract to its stowed position. This creates THREE safety hazards: 1.Passenger Trip Hazard: The extended belt causes difficulty when exiting from the rear seat — passengers can easily trip over the non-retracting belt 2.Door Damage Risk: Belt gets stuck in the door, preventing proper closure and potentially damaging the door or wearing down the seat belt webbing 3.Safety System Failure: A belt that doesn’t retract properly may not fully restrain occupants in a crash, compromising the seat belt safety system Dealer Response: My dealership told me this is “out of pocket” repair cost, even though the identical retraction issue exists in 2017–2021 C-Class Cabriolet (A205 platform) vehicles that ARE covered under Safety Recall 21V-032000. Mercedes fixed this with damping foam adjustment in the recalled Cabriolets but is refusing the same repair on C300 Coupes. Defect Pattern: This is the same design flaw in the front seat belt retractor geometry that caused the recall. The distance between the retractor and damping foam within the B-pillar doesn’t meet production specifications. Safety Risk: If occupants find the belt inconvenient due to poor retraction, they may not wear it — increasing crash injury risk. No advance warning of retractor failure exists. Request: NHTSA should investigate whether the C300 Coupe should be included in this recall or if a separate recall is needed for the same defect. Vehicle Info: 2019 Mercedes-Benz C300 Coupe

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.

The contact owns a 2019 Mercedes-Benz C300. The contact stated that while driving and attempting to close the sunroof, the sunroof made an abnormal popping sound. The contact pulled over and attempted to close the sunroof, but the sunroof failed to close. The contact related the failure to NHTSA Campaign Number: 21V197000 (Structure); however, the VIN was not associated with the recall. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. The manufacturer was not contacted. The failure mileage was approximately 53,000.

Odometer Fraud. The contact purchased a 2019 Mercedes-Benz C300. The contact stated that after purchasing the vehicle, it was discovered that there was a mileage discrepancy. The vehicle was a dealer sale. The contact stated that at the time of purchase, the odometer reading was approximately 54,000 miles. At the time of registration, the mileage was approximately 54,000 miles, and the same mileage was also reflected on the Carfax report. The contact stated that the mileage discrepancy was later discovered through a public report with the Federal Trade Commission (FTC); however, the mileage was not provided. The contact stated that the mileage discrepancy occurred after two OTA’s were performed on the vehicle. The contact stated that during the OTA’s on the vehicle, the mileage was changed. The contact stated that several documents with the mileage discrepancies were listed with the FTC. The contact also reported the discrepancy to the Department of Motor Vehicles.

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!!

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.

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.

The contact owns a 2019 Mercedes-Benz C300. The contact stated that the convertible top support were fraying. The contact stated the parts were almost the thickness of a shoelace and enabled the convertible top to fold correctly when the top was folding down. The contact stated that the Part Number was A2057780500. The contact had taken the vehicle to a local dealer, where it was diagnosed, and the dealer determined that the entire convertible top needed to be replaced. The vehicle was not repaired. The manufacturer was informed of the failure, and the contact filed a case. The failure mileage was approximately 43,000.