2021 Mercedes-Benz C-Class problems and complaints

Owners have filed 15 complaints with NHTSA about the 2021 Mercedes-Benz C-Class. The most-reported areas: Engine (8), Power Train (2), Air Bags (2).

Key takeaways

  • 15 owner complaints on file with NHTSA.
  • 0 involve a crash, 0 a fire, 0 reported injuries.
  • Complaints are unverified owner reports; recalls are confirmed defects.
Complaints by component
ComponentComplaintsShare
Engine853%
Power Train213%
Air Bags213%
Fuel/Propulsion System213%
Fuel System17%
Gasoline17%
Visibility17%
Suspension17%
Back Over Prevention17%
Electrical System17%

One complaint can name several components, so shares add up to more than 100%.

NHTSA 5-Star crash ratings
VersionOverallFrontSideRollover
2021 Mercedes-Benz C-Class 2 DR RWDNot ratedNot ratedNot ratedNot rated
2021 Mercedes-Benz C-Class 4 DR RWD5/54/55/54/5
2021 Mercedes-Benz C-Class 2 DR 4WDNot ratedNot ratedNot ratedNot rated
2021 Mercedes-Benz C-Class 4 DR 4WD5/54/55/54/5

Latest complaints, as filed

Owner-written and unverified by NHTSA.

Engine - filed 2026-08-07

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 th...

Fuel System, Gasoline - filed 2026-05-19

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 m...

Visibility - filed 2026-01-20

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 wi...

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More for the 2021 Mercedes-Benz C-Class

Complaints are reports filed by owners with the National Highway Traffic Safety Administration. NHTSA publishes them without verifying them, and counts rise with how many cars were sold, so compare years of the same model rather than different models. Crash ratings are NHTSA's own 5-Star Safety Ratings results.