2019 Mercedes-Benz C300 engine problems

Filed Nov 6, 2026 · Engine, Fuel system · NY

A 55,000 miles vehicle - escalated to a $10,000. repairs - Coolant Leakage and SOLENOID related issues - the mental duress and stress from a unreasonable cost and seriousness of repaire requireements as the car got just out of the warranty period.

Filed Sep 21, 2026 · Engine, Transmission · CA

The M264 2.0L engine suffered a catastrophic internal failure. While making a left turn at an intersection, the vehicle suddenly shut off and stalled, leaving the car stranded in active traffic and creating an immediate safety risk. Prior to the shutdown, the check engine light came on accompanied by severe shaking and misfires. The vehicle was inspected by an authorized dealership service center, which confirmed complete engine failure. Mercedes-Benz issued a 15-year/150,000-mile extended warranty for the M264 exhaust valve and cylinder head assembly, but warranty coverage was refused because the cylinder defect progressed to total engine destruction. The vehicle remains available for inspection upon request.

Filed Sep 15, 2026 · Electrical, Engine · CA

The vehicle experienced a severe safety issue involving a sudden loss of motive power in active traffic. 1. Initial Symptoms & Diagnosis: Recently, the Check Engine Light illuminated. Although the light turned off before my scheduled appointment, I still brought the vehicle to an authorized Mercedes-Benz dealership for a safety inspection. 2. Dealer Confirmation: The dealership inspected the vehicle and diagnosed an internal electrical fault with the engine oil control valve and harness. They recommended replacing the parts. Because the vehicle seemed to be running fine and the dealer did not warn me that it was unsafe to drive, I drove the vehicle home to consider the repair. 3. Critical Safety Incident: Shortly after bringing the car home, I was stopped at an intersection. When I attempted to accelerate, the vehicle suddenly entered "limp mode." It lost almost all motive power and would only crawl forward at a very low speed. This sudden loss of acceleration in the middle of traffic put me at an immediate risk of a collision. I had to pull over to the side of the road and restart the engine to regain normal function. 4. Prior Symptom: Looking back, I experienced a similar brief loss of power approximately one year ago. However, the vehicle recovered quickly after I restarted the engine, and no warning lights came on, so I was unaware of the severity of the defect at the time. The vehicle has less than 20,000 miles. An internal engine valve failure causing a sudden loss of acceleration on public roads is a major safety defect. The vehicle is currently parked for safety reasons and is available for inspection upon request.

Filed Jul 1, 2026 · Electrical, Engine · FL

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 the federal safety agency investigation and order manufacturer to repair under Service Campaign 2022090005 at no charge.

Filed May 19, 2026 · Engine · GA

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.

Filed Jan 22, 2026 · Engine · TN

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!!

Filed Jan 5, 2026 · Acceleration, Electrical · CA

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.

Filed Dec 22, 2025 · Engine, Fuel system · FL

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.

Filed Oct 4, 2025 · Electrical, Engine · CA

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)

Filed May 30, 2025 · Acceleration, Electrical · CA

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)