2021 Mercedes-Benz C 300: problems, recalls and reliability
7 recalls and 14 owner complaints on record; most reports concern engine.
Data updated weekly · latest recall Jun 2023
All counts are reports filed with NHTSA in the United States - US market only, not worldwide totals.
Common problems
Computed from 14 owner complaints filed with NHTSA for this exact model year.
“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. The approximate failure mileage was 60,000.”Owner report · Fuel System, Gasoline · Mar 2026
“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.”Owner report · Fuel/Propulsion System · Nov 2025
“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 misfires create a safety risk of engine failure or fire while driving. TSB NUMBER LI07.16-P-074000 (February 2023, updated multiple times). This is a known production/early break-in issue with the M254 engine, not the result of owner misuse or delayed maintenance.”Owner report · Engine · Oct 2025
Show 6 more owner reports
“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.”Owner report · Fuel/Propulsion System · Oct 2025
“Cylinder head needed to be replaced on the M264 engine at 35,000 miles. The replacement part is also known to be defective for the same reasons. This is a common defect known to the manufacturer and they have not issued a recall. My concern is that of a roadside breakdown that would endanger my wife and myself. Thank you for your consideration.”Owner report · Engine · Feb 2025
“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 engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The contact stated that the engine was previously repaired because of the head gasket failure in 2024. The manufacturer was informed of the issue, and a case was opened. The failure mileage was approximately 88,000.”Owner report · Engine · Aug 2024
“the check Engine light fault code P012D12 The pressure sensor upstream of the turbocharger had a short circuit to positive. Found Kink wire on upstream pressure sensor. A short circuit to positive. Electrical Wire replaced.”Owner report · Engine · Jul 2023
“Piston Connecting Rod broke and left the engine making holes in both sides of the block; Mercedes Benz rejected any responsibility because the car has a branded title. Currently a new engine (brand new) is being installed, my concern is that what will happen if the new engine has the same defective part and blew up again.”Owner report · Engine · May 2023
“The contact owns a 2021 Mercedes-Benz C300. The contact stated while driving at an unknown speed, there was a burning odor inside the vehicle. The contact stated the passenger side air bags was enabled warning light was illuminated. The contact also stated the vehicle made an abnormal noise. The contact took the vehicle to the local dealer but was unable to duplicate the failure. The manufacturer had not been informed of the failure. The failure mileage was unknown.”Owner report · Air Bags · Nov 2021
Recalls - 7 campaigns
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2017-2022 CLA-Class, GLA-Class, GLE-Class, GLS-Class, SLC-Class, A-Class, AMG GT-Class, C-Class, E-Class, S-Class, SL-Class, GLC-Class, CLS-Class, GLB-Class, and G-Class vehicles. Please refer to MBUSA's recall report for specific vehicle model details. An error in the communication module's SIM card software can cause a mobile network connection failure, disabling the emergency call (eCall) system.
Remedy: The communication module software will be updated through an Over-the-Air (OTA) update or by a dealer, free of charge. Owner notification letters were mailed July 8, 2022. Owner notification letters will be mailed in phases, on July 8, 2022, May 17, 2024, July 29, 2024, and September 27, 2024. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's numbers are for this recall is 2022060005 and 2023110006.
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2021 C300 Cabriolet, C43 AMG Cabriolet, C63 AMG Cabriolet, C63 AMG S Cabriolet, E450 Cabriolet, and E53 AMG Cabriolet vehicles. The rear headrests may be incorrectly mounted to the seatbacks.
Remedy: Dealers will inspect the rear seatback guide bushings and replace them if necessary, free of charge. Owner notification letters were mailed July 16, 2021. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2021060010.
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2021-2023 C-Class, E-Class, S-Class, CLS, SL, GT, GLC, GLE, GLS, and G-Class vehicles. Please refer to MBUSA's recall report for specific vehicle details. The fuel pump may shutdown, which can result in a loss of drive power.
Remedy: Dealers will replace the fuel pump, free of charge. Owner notification letters were mailed on June 14, 2024. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2023070012.
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2017-2021 C300, 2017-2020 AMG C43, and AMG C63 vehicles. The front seat belts might not fully retract to their stowed position. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 208, "Occupant Crash Protection."
Remedy: MBUSA will notify owners, and dealers will check the retraction function of the front seat belts and adjust the damping foam within the B-pillars, as necessary, free of charge. The recall began February 26, 2021. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2021020010.
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2016 - 2021 CLA-Class, GLA-Class, GLE-Class, GLS-Class, SLC-Class, A-Class, GT-Class, C-Class, E-Class, S-Class, CLS-Class, SL-Class, B-Class, GLB-Class, GLC-Class, and G-Class vehicles. Please refer to the Part 573 report for specific vehicle model details. The software design of the communication module may fail to communicate the correct vehicle location for the emergency call system (eCall) in the event of a crash.
Remedy: MBUSA will notify owners, and the communication module software will be updated by a dealer, or through an over-the-air (OTA) update, free of charge. The recall began March 12, 2021. Owners may contact MBUSA customer service at 1-877-762-8267. MBUSA's number for this recall is 2021020025.
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2018-2021 CLA-Class, GLE/GLS-Class, A-Class, C-Class, E-Class, E-Class Coupe/Convertible, GLA/GLB-Class, GLC-Class, and CLS-Class vehicles. Please refer to MBUSA's recall report for specific vehicle model details. The rearview camera may not display the rearview image due to a software error. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 111, "Rear Visibility."
Remedy: Dealers will update the rearview camera software, free of charge. Owner notification letters were mailed July 15, 2022. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2022060007.
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2021 C-Class, E-Class, E-Class Coupe and Convertible, GLC, CLS, AMG GT 4-door Coupe and G-Class vehicles. Please refer to MBUSA's recall report for specific vehicle model details. A faulty electrical contact within the seat position switch may prevent the driver and passenger air bags and seat belt force limiters from properly activating during a crash.
Remedy: MBUSA will notify owners, and dealers will replace the seat position switches, free of charge. Owner letters were mailed May 21, 2021. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2021040016.
How other years compare
Check your exact C 300 by VIN
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Is the 2021 Mercedes-Benz C 300 reliable?
NHTSA has 14 owner complaints and 7 recall campaigns on record for the 2021 Mercedes-Benz C 300. The most complained-about area is engine.
Does the 2021 Mercedes-Benz C 300 have open recalls?
7 recall campaigns have been issued, the latest concerning electrical system:software. Check your specific vehicle by VIN - recall repairs are free at franchised dealers.
Source: NHTSA recall campaigns and owner complaints (public domain). Counts reflect reports on file and are not a defect rate.