2021 Mercedes-Benz C-Class Cabriolet recalls & complaints
Source: NHTSA, updated daily. Last checked 2026-10-19. Recalls apply to specific VINs — run your VIN to confirm.
Recalls: check by VIN
Useful for owners
- OBD2 code reader — see what the car's computer is reporting
- 2021 Mercedes-Benz C-Class Cabriolet owner's manual
Owner complaints filed with NHTSA
Most complained-about parts: Engine (8), Fuel system (3), Gasoline (1), Visibility (wipers / glass) (1), Transmission / drivetrain (1).
Complaints are unverified reports from owners. A pattern (many complaints about the same part) matters more than any single one.
Read recent complaints (8)
08/07/2026 · Engine
The contact owns a 2021 Mercedes-Benz C 300. The contact stated that while depressing the accelerator pedal, there was a loud knocking sound coming from the engine compartment while accelerating. There were no warning lights illuminated. The vehicle was taken to the dealer to be diagnosed, and it was determined that the spawn rod was fractured, causing engi…
05/19/2026 · Fuel system
The contact owns a 2021 Mercedes Benz C. The contact stated that while driving on the highway, the vehicle began to lose power, riding rough. The check engine light illuminated. The vehicle was towed to the dealer where it was diagnosed with a fuel injection failure. The vehicle read diagnostic code P1CEF85. The manufacturer was made aware of the issue…
01/20/2026 · Visibility (wipers / glass)
I am reporting a safety defect involving the panoramic sunroof on my 2021Mercedes-Benz Coop vehicle. The panoramic sunroof has malfunctioned due to an apparent design or manufacturing defect. The sunroof fails to open / close and makes grinding or popping noises which malfunctioned unexpectedly. This issue occurred without misuse and during normal operatio…
12/22/2025 · Engine
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…
11/25/2025 · Fuel system
My car had a coolant leak last year a hose broke and I have a 2021. My son’s mercedes sis the same thing on 11/23/2025. I have researched ma y others with this same issue. There should be a recall on that hose or whatever the problem Is.
11/25/2025 · Engine
2021 Mercedes-Benz C300 with M254 2.0L turbo engine experienced sudden cylinder head failure at 44,000 miles due to manufacturing porosity in the cylinder head and camshaft bore scoring. Dealer confirmed defect. This is a known, recurring issue on 2021–2023 M254 engines with multiple documented failures under 50k miles. Sudden loss of compression and misfir…
10/06/2025 · Fuel system
While driving car on Sunday 10/5, it suddenly failed to respond to gas pedal pressure. The car stopped accelerating and rather slowed to 15 MPH, almost causing a car from behind to hit me in the rear side.
08/06/2025 · Transmission / drivetrain
My C300 only had about 42,000 miles and was less than 5 years old. Just after the factory warranty expired, the engine was running rough and hot, and "check engine" light illuminated. My local garage quickly diagnosed the problem as a failed cylinder head, stated that it is common with Mercedes 4-cylinder engines from about 2017, and said Mercedes may cover…