Mercedes-Benz C300 stalling problems

Filed Nov 3, 2026 · Brakes, Transmission · 122,820 miles · NJ

The contact owns a 2020 Mercedes-Benz C-300. The contact stated that while driving at an undisclosed speed, the brake pedal was depressed, and the brake pedal was abnormally difficult to depress. In addition, the contact became aware of an abnormal sound coming from the footwell. The dealer was contacted and made aware of the failure. The vehicle was taken to the dealer; however, the failure was not duplicated. The failure then reoccurred. The contact stated that while driving 35 MPH, the vehicle stalled and the vehicle lost motive power. In addition, several unknown warning lights illuminated, and the transmission shifted to neutral(N). The contact stated that a nearby independent mechanic assisted with removing the vehicle out of the roadway and onto the shoulder of the roadway. The independent mechanic attached a portable diagnostic scanner to the vehicle. The contact stated that while attempting to start the vehicle, the vehicle started. The vehicle was taken to an independent mechanic where it was diagnosed with ABS Module failure. The contact was informed that the ABS module needed to be replaced. The dealer was contacted and made aware of the failure. The manufacturer was contacted, and a case was filed. The failure mileage was approximately 122,820.

Filed Oct 27, 2026 · Engine, Fuel system · OH

Hi, in the Fall of 2025 my 2016 Mercedes Benz C300 4 Matic, started giving off smelly fumes while my car was idling/ warming up. I registered a complaint with the Corporate Mercedes Benz Office USA, LLC in April 2026 @ 800‑367‑6372, after the dealership would not correct the issue free of charge. 1. Hose Clamp Replacement problems. 2. The raw fuel leakage produces strong gasoline odors inside the cabin- via the air filter, risk of car stalling and the smell could be leathal. 3. The problem was confirmed in a lawsuit. 4. The dealership would not repair the issue. 5. There were no warning lamps or messages on the dash board, the only essential issue were the smells, fumes, odors and lawsuit.

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 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 Apr 27, 2026 · Electrical, Fuel system · CA

I’ve been driving my car since September when it was purchased I just got it from dealership 4/9/26 spent over $1100 and have been working like regular full time schedule, I wake up today 4/27/26 trying to work and car is stalling. Not sure what’s going on with these mechanics and technicians. I pay to dollar to ensure my family safety on the road here I am stuck without support due to my circumstances. Also, my car just idles the shuts off doesn’t turn mall the way on, magically a check engine light flashed then car just immediately stalled and won’t turn back over all the way.

Filed Feb 17, 2026 · Engine · GA

I am reporting a catastrophic repeat engine failure on my 2020 Mercedes-Benz C300. On October 9, 2025, with 26,589 miles, the vehicle suffered a Cylinder 2 failure (exhaust valves), causing a dangerous loss of power in traffic. I paid $4,100.43 for a $10,000 plus cylinder head replacement at an authorized dealer (Mercedes-Benz of Atlanta South) on November 13, 2025. Following the repair, the vehicle continued to exhibit multiple 'Check Engine Oil Level' warnings. On February 4, 2026—less than 90 days after the major repair—the engine suffered a total catastrophic failure. The dealer now states the entire engine requires replacement. This repeat failure of a critical engine component at low mileage poses an unreasonable risk of stalling or sudden loss of propulsion on high-speed roads. I am aware of the January 2026 Mercedes-Benz warranty extension (NCU 30-P-072328) for this specific M264 engine defect, which confirms a known manufacturing flaw that the current dealership repair process failed to remediate, leaving me in an unsafe vehicle.

Filed Dec 22, 2025 · Engine · 86,078 miles · NJ

The contact owns a 2021 Mercedes-Benz C300. The contact stated that while driving at an undisclosed speed, the vehicle stalled and failed to exceed 30 MPH, with the check engine warning light illuminated. The vehicle did not require a restart. The contact also stated that while stopped at a traffic light, the vehicle was shaking abnormally. The vehicle was taken to an independent mechanic, where it was diagnosed and determined that there was a misfire in cylinder #2. The contact was informed that the cylinder head needed to be replaced. The vehicle was not repaired. The vehicle was then taken to the dealer, where the same diagnostic information was provided, and the contact was informed that the cylinder head needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 86,078.

Filed Nov 19, 2025 · Acceleration, Fuel system · GA

1. The vehicle experienced a fuel injector failure, which is part of the engine fuel delivery system. This failure appears connected to an open Fuel System Control Unit Software Update Recall (Campaign 2024080006) that has been open since May 2024 but was not performed on my vehicle, despite the vehicle being serviced at the dealership in January 2025 for other recall-related updates. The failed injector is still available for inspection upon request. 2. The vehicle began exhibiting symptoms of fuel system malfunction while driving, including rough idling, hesitation, and loss of power. A malfunctioning injector can cause the engine to misfire, stall unexpectedly, or run unpredictably, which creates a high-risk situation in traffic. This placed me, my passengers, and other drivers at risk, especially during acceleration or when merging into traffic. 3. Yes. The issue was diagnosed and confirmed by the Mercedes-Benz dealership, which stated that the injector had mechanically failed. The dealership also noted the open recall for the fuel system software update but claimed it was unrelated. I am seeking clarification because the timing and symptoms suggest there may be a connection. 4. The vehicle has been inspected only by the Mercedes-Benz dealership. Mercedes-Benz USA (MBUSA) has been contacted regarding the issue, but my case was closed without resolution and is currently awaiting review for reopening. MBUSA has not yet inspected the vehicle or the failed component directly. 5.Prior to the injector failure, the vehicle displayed engine hesitation, rough idling, and intermittent performance issues. Eventually, a check engine light illuminated. These symptoms began before the manufacturer-installed software update, and the issue appears to have worsened afterward.

Filed Oct 26, 2025 · Engine, Fuel system · GA

I purchased this 2020 Mercedes-Benz C300 only two months ago and have driven it less than 3,000 miles. The Carfax report shows consistent maintenance and regular service history by prior owners. While driving, the check engine light came on and the vehicle began shaking and running roughly. Diagnostics by Peachtree Imports (10/03/2025) and later by Mercedes-Benz of Atlanta South confirmed Cylinder #2 failure on the M264 2.0L engine at only 26,589 miles. The dealer’s report states: “Cylinder #2 mixture formation out of spec. Fault occurred due to worn exhaust valve seat. Cylinder head replacement required.” Estimated repair cost: $10,470.66. This causes misfire, loss of power, and unsafe drivability. The failure matches Mercedes-Benz Technical Service Bulletin LI01.30-P-072328 (2021), which documents valve-seat leakage in M264 engines requiring head replacement. The vehicle is outside warranty but has extremely low mileage, and MBUSA Case #18392667 remains unresolved. It is also important to note that the M260 engine, which is mechanically identical to the M264 but mounted transversely, has already received a warranty extension from Mercedes-Benz for the same cylinder-head and valve-seat defect. This indicates a systemic issue across both engine families, presenting a safety risk of sudden power loss or engine stall during operation.

Filed Aug 6, 2025 · Engine, Steering · 82,000 miles · TX

The contact owns a 2015 Mercedes-Benz C300. The contact stated while driving 40 MPH, the vehicle unexpectedly veered to the left. There was no warning light illuminated. The contact stated that the steering wheel became inoperable, and the contact was unable to straighten the steering wheel. The brake pedal was also depressed. The contact attempted to depress the accelerator pedal however, the vehicle started to stall. The contact pulled over into a parking lot and was able to restart the vehicle. The dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 82,000.