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.
The worst 2020 Mercedes-Benz C300 problems
Ranked by number of owner complaints. Mileage and cost come from what owners wrote.
Problems by type
Tap a problem to see which part fails, at what mileage and in which other years.
- Engine8
- Driver assistance6
- Body4
- Transmission4
- Electrical3
- Fuel system3
- Visibility3
- Acceleration2
- Airbags2
- Brakes2
- Locks2
- Steering2
- Tires2
Specific symptoms reported on the 2020 Mercedes-Benz C300
Recalls 9
Structure: body: roof and pillars
- What is wrong
- Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2014-2020 C-Class, CLA, GLA, S-Class, GLC, and GLE vehicles. Please refer to MBUSA's recall report for specific vehicle details. The front roof panel located between the windshield and the panoramic sunroof may not have been bonded correctly to the vehicle during a prior repair, allowing the front panel to detach from the vehicle.
- Risk
- A detached roof panel can become a road hazard, increasing the risk of a crash.
- Remedy
- Dealers will replace the front panel, free of charge. Owner notification letters were mailed on August 2, 2024. Owner notification letters will be mailed in phases, on, March 22,2024, and August 2, 2024. Owners may contact MBUSA customer service at 1‑800‑367‑6372. This recall is an expansion of the federal safety agency recall number 21V‑197.
Recall number 23V854000 · Recall details
Electrical system: software
- What is wrong
- 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.
- Risk
- A disabled eCall system would prevent a vehicle occupant from contacting the emergency services call center in an emergency, potentially delaying emergency responders and increasing the risk of injury.
- 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.
Recall number 22V365000 · Recall details
Back over prevention: display function
- What is wrong
- 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."
- Risk
- An inoperable rearview camera display reduces the driver's rear view, increasing the risk of a crash.
- 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.
Recall number 22V232000 · Recall details
Exterior lighting: headlights
- What is wrong
- Mercedes-Benz LLC (MBUSA) is recalling certain 2018-2020 C300, 2019-2020 A220, AMG C43, AMG C63, 2020 GLE580, GLB250, 2020-2021 GLE450, GLE350, 2021 AMG GLE63, and AMG GLE53 vehicles. The LED headlights may have been incorrectly adjusted during a vehicle repair. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 108, "Lamps, Reflective Devices, and Associated Equipment."
- Risk
- Incorrectly adjusted headlights may reduce visibility, increasing the risk of a crash.
- Remedy
- Dealers will replace the LED headlights, free of charge. Interim letters notifying owners of the safety risk were mailed August 13, 2021. A second notice will be sent once the remedy is available. Owner notification letters were mailed January 2022. Owners may contact MBUSA customer service at 1‑800‑367‑6372.
Recall number 21V509000 · Recall details
Structure: body: roof and pillars
- What is wrong
- Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2017-2020 C300 Coupe, C43 Coupe AMG, C43 AMG, 2015-2020 C300, GLA250, 2016-2018 C350e, CLA45 Coupe AMG, 2015 C400, S65 AMG, 2015-2019 C63 AMG, 2016 C450, 2015-2016 GLA45 AMG, S600, 2016-2020 GLC300, 2017-2019 GLC43 AMG, GLE43 Coupe AMG, 2014-2019 CLA250 Coupe, 2014-2015 CLA45 AMG, 2018 GLC63 AMG, 2014-2017 S550, 2018-2020 S450, 2016-2019 GLE63 Coupe AMG, 2016 GLE450 Coupe, 2014-2020 S63 AMG, 2018-2019 S560, and 2019 GLC350e vehicles equipped with a panoramic sunroof. The front roof panel located between the windshield and the panoramic sunroof may not have been bonded correctly to the vehicle during a prior repair.
- Risk
- The adhesive bonding of the front panel might deteriorate, possibly causing the front panel to detach from the vehicle and become a road hazard, increasing the risk of a crash.
- Remedy
- Mercedes-Benz dealer will remove the bonded panel and will install a new front panel by following the detailed repair instructions and using the approved primer, cleaner and adhesive, free of charge. Owner notification letters were mailed on September 3, 2021 and October 26, 2021. Owners may contact MBUSA customer service at 1‑800‑367‑6372.
Recall number 21V197000 · Recall details
Electrical system: software
- What is wrong
- 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.
- Risk
- Failure of the eCall system may result in emergency responders being dispatched to the wrong location, increasing the risk of injury following 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.
Recall number 21V058000 · Recall details
Seat belts: front: retractor
- What is wrong
- 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."
- Risk
- If the seat belt does not fully retract, the occupant may find the operation of the seat belt inconvenient and not wear it, increasing the risk of injury in the event of a crash.
- 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.
Recall number 21V032000 · Recall details
Engine and engine cooling: engine: gasoline: turbo/supercharger
- What is wrong
- Mercedes-Benz USA, LLC. (MBUSA) is recalling certain 2020 C300, E350, and GLC300 vehicles equipped with turbocharged 4-cylinder gasoline engines. The screws that retain the turbocharger oil feed and return lines may not have been properly tightened, possibly resulting in an oil leak.
- Risk
- An oil leak in the presence of an ignition source such as hot engine or exhaust components can increase the risk of a fire.
- Remedy
- MBUSA will notify owners, and dealers will inspect the turbocharger oil lines and tighten them as necessary, free of charge. The recall began August 17, 2020. Owners may contact MBUSA customer service at 1‑800‑367‑6372. MBUSA's number for this recall is 2020070017.
Recall number 20V364000 · Recall details
Communication
- What is wrong
- Mercedes-Benz USA, LLC. (MBUSA) is recalling certain 2020 C300 Cabrio, C300 Cabrio 4MATIC, C300 Coupe, C43 AMG Cabrio 4MATIC, C43 AMG Coupe 4MATIC, C63S AMG Cabrio, CLS53 AMG 4MATIC, E350, E350 4MATIC, E450 Cabrio, E450 Cabrio 4MATIC, E450 Coupe, E450 Coupe 4MATIC, E450 4MATIC, E53 AMG Cabrio 4MATIC, GLC300 Coupe 4MATIC, GLC300, GLC300 4MATIC, GLC63 AMG Coupe 4MATIC, AMG GT63 4-Door 4MATIC, and AMG GT63S 4-Door 4MATIC vehicles. An electrical circuit inside the Emergency Call System (eCall) communication module may be damaged, potentially relaying an inaccurate vehicle location.
- Risk
- An inaccurate vehicle location may delay emergency responders, increasing the risk of injury.
- Remedy
- MBUSA will notify owners, and dealers will replace the communication module, free of charge. The recall began April 14, 2020. Owners may contact MBUSA customer service at 1‑800‑367‑6372. MBUSA's number for this recall is 2020030016.
Recall number 20V068000 · Recall details
See all 9 recalls for the 2020 Mercedes-Benz C300
Defect investigations
Front Roof Panel Detachment
On January 8, 2021, after ongoing review with Mercedes Benz, the federal safety agency Office of Defects Investigation (ODI) opened PE21-001 to assess allegations of front roof panel detachments while driving at highway speeds in certain 2015 Mercedes-Benz (Mercedes) C-Class vehicles.The subject front roof panel is a stationary panel composed of polycarbonate and is attached to the vehicle via adhesive at the time of manufacture. The panel is found on subject vehicles equipped with panoramic sunroofs. Over time, the subject panels may exhibit cosmetic degradation leading to replacement of the panel, a procedure which entails: removal of the old panel and adhesive, site preparation, and installation of a replacement panel with new adhesive.The consumer complaints that prompted the opening of PE21-001 all described detachments of front roof panels that had been replaced after the vehicle was put into service.Mercedes' internal investigation identified a broader scope of affected vehicles (2014-2020 CLA, GLA, C, S, GLC, and GLE class) and found the following potential service procedure- related causes of front roof panel detachments:- Improper surface pretreatments such as the use of the wrong primer or cleaner or scoring of the surface; or - Use of the incorrect adhesive.These conditions lead to a front roof panel bond that, even if sound at the time of repair, cannot maintain its strength over time and environmental exposure.Mercedes updated its service and parts ordering systems to reinforce the proper use of specified kits and procedures via webinars, shop foreman meetings, and explicit reference to the risks incurred by diverging from the repair procedures. Mercedes is also furnishing parts ordering assistance, and will hold dealerships accountable for improper repairs.ODI's analysis of the ten complaints it has received from the public (VOQ's) and MBUSA's complaint data submitted in response to the information request letter for PE21-001 identified a total of 57 non-duplicative reports alleging incidents in which the front roof panel detached from the vehicle while in motion. Included within the 57 reports are incidents where consumers state the panel detached ...and flew off into traffic.On March 19, 2021, Mercedes notified the federal safety agency that it would recall subject vehicles with front roof panels known to have been replaced after the original sale of the vehicle. In total, the recall (designated as Recall 21V197) covers 15,099 vehicles that were ever registered in the United States. Based on Recall 21V197 and the remedy implemented by Mercedes, further investigation does not appear to be warranted at this time.Accordingly, this investigation is closed.The ODI complaints cited above can be viewed at under the following ODI identification numbers: 11376425, 11352686, 11351629, 11349158, 11341541, 11337594, 11324100, 11311591, 11222127, 11404183
PE21001
Technical service bulletins for the 2020 Mercedes-Benz C300 183
Bulletins tell dealers how to fix known problems. A warranty extension means the manufacturer pays for that repair for longer.
- Dear Mercedes-Benz Owner: In our continuing efforts to ensure the proper performance of Mercedes-Benz...
- Fuel/propulsion system
- In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the...
- In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the...
- Customer complaints relating to automatic transmission 725.0 (NAG3 Classic /9G‑TRONIC automatic...
- Repeat workshop visit for vehicle vibration while braking from 60MPH. NOTE: Although the symptom is...
- Only vehicles with a variable transfer case are affected
- Clanking noise from the area of the speakers in the doors
- Customer complaints relating to automatic transmission 725.0 (NAG3 Classic / 9G‑TRONIC automatic...
- During part of the steering movement, it feels heavier or more difficult to steer in the same spot every time
What 2020 Mercedes-Benz C300 owners say
Most recent owner complaints, unedited.
I own a 2020 Mercedes-Benz C300 equipped with a power trunk. On July 22, 2026, I took my vehicle to Annapolis Mercedes-Benz because the power trunk was repeatedly closing on its own while people were standing in the trunk opening. I specifically reported that the trunk was unexpectedly closing while I, my child, or another individual was loading or unloading the vehicle and expressed concern that someone could be injured. The dealership kept the vehicle for several hours but advised me that no malfunction could be found. I was told the trunk had been reset and that there were no problems with the vehicle. I also provided video evidence of the trunk malfunction by text message to my service advisor. On August 2, 2026, the exact same problem occurred. While I was loading groceries into the trunk, the power trunk unexpectedly closed without warning and struck my son in the head, causing injury. This incident occurred after I had already reported the same safety concern to the dealership. I believe the power trunk is malfunctioning intermittently and presents a significant safety hazard because it can unexpectedly close on a person while the trunk is being used. I am requesting that the federal safety agency investigate this potential safety defect, as it may pose a risk of injury to other vehicle owners and passengers.
Automatic trunk closing mechanism caused the trunk hood to close on my head as I was putting groceries in the trunk. This has occurred several times in the past but this time it hit my head with more force. I have not brought it to a dealer and it has not been inspected by the manufacturer, police or any other entity. There was no warning or alarm before it closed. This could cause serious head injury to an individual on blood thinners.
Vehicle has ongoing and recurring electrical and engine-related defects that affect safe operation. The primary systems involved are the electrical system, engine ignition system, and powertrain. The vehicle is available for inspection upon request. Prior service records show issues beginning in 2020 involving repeated electronic system failures requiring multiple repairs and component replacements. Since purchasing the vehicle in April 2023, the vehicle has developed more serious failures, including: – September 2024: Check engine light with loss of power and inability to exceed safe driving speeds – October 2024: Engine misfiring due to ignition coil failure requiring replacement of ignition components – September 2025: Additional ignition coil electrical fault (code P0353) The problem has been reproduced and confirmed through dealership service inspections and diagnostic reports. Warning indicators, including the check engine light, appeared prior to failure events. These defects create a safety risk due to potential loss of power, engine failure, and unreliable vehicle operation while driving, which could increase the risk of an accident. The issues have required multiple repairs without permanent resolution and appear to be ongoing and worsening over time.
The contact owns a 2020 Mercedes-Benz C300. The contact stated that while at a stop, the vehicle failed to accelerate as intended. There was no warning light illuminated. The dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure and referred the contact to the federal safety agency Hotline to report the failure. The failure mileage was approximately 100,000.
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.
I purchased this vehicle on December 26, 2025 from an authorized Mercedes-Benz dealership. Shortly after the purchase, I discovered an issue related to the airbag system, which indicates a potential safety defect. At the time of purchase and during the test drive, the vehicle was already turned on, and no warning or disclosure was provided regarding any airbag malfunction or warning message. The issue became apparent only after the purchase. I later brought the vehicle in for repairs. While some repairs were performed, the airbag issue was not fixed and remains in the same condition as before. The dealership is now refusing to repair the airbag system at no cost and is insisting that I pay for the repair, despite the fact that this defect appeared immediately after purchase and was never disclosed to me. I believe this represents a serious safety concern, as a malfunctioning airbag system may fail to protect occupants in the event of an accident. I also believe the vehicle was sold to me with an undisclosed safety defect. I am requesting that this issue be formally reviewed and investigated.
points: ⸻ While driving, the vehicle displays the warning “Active Brake Assist Functions Limited – See Operator’s Manual.” The message appears during normal driving and does not go away. This warning indicates that the automatic emergency braking / Active Brake Assist system is limited or disabled, reducing a critical safety feature designed to help prevent or mitigate collisions. This creates a safety risk because the vehicle may not automatically brake in an emergency situation. The warning appeared suddenly while driving, with no visible obstructions, weather conditions, or damage to sensors. Restarting the vehicle does not consistently clear the message. The issue has not yet been inspected by a dealer or repair facility. The cause of the malfunction is UNKNOWN, and the vehicle is available for inspection.
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.
BOTH the front tires in my 2020 Mercedes C300 developed sudden belt separation while driving at highway speed this past weekend. These tires were installed by Mercedes of Delray Beach Florida as part of my CPO vehicle purchase in September of 2022 and have less-than 20K miles on them. Tires are Continental ProContact size 225/45 R18 and marked M+S as well as MOE. The vehicle received a routine four-wheel alignment as part of my annual servicing in July 2025 by Mercedes of Fort Pierce, and no indication of any tire issue was mentioned. Tire pressures have been consistently checked monthly and always set cold to 37-PSI specifications. The first indication of a tire issue was a sudden vibration in the steering wheel and I thought I may have lost a wheel weight after driving thru our local car wash the day prior.
Compare the 2020 Mercedes-Benz C300
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Other model years
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Questions about the 2020 Mercedes-Benz C300
Is the 2020 Mercedes-Benz C300 reliable?
Owners have filed 34 complaints about the 2020 Mercedes-Benz C300, fewer than a typical C300 model year.
What is the 2020 Mercedes-Benz C300 year score?
The 2020 Mercedes-Benz C300 scores 78 out of 100 (average). The score compares it with the other model years of the Mercedes-Benz C300: 75 is a typical year, 50 means twice the usual complaints, and serious complaints and recalls lower it.
What is the most common problem with the 2020 Mercedes-Benz C300?
Engine and cooling, with 8 complaints. Next is driver assistance (6).
How many recalls does the 2020 Mercedes-Benz C300 have?
9 recalls, covering structure, electrical system and back over prevention.
Was there a recall on the 2020 Mercedes-Benz C300 engine?
Yes, 1 recall: 20V364000. Check your VIN to see if your car still needs the free repair.
What year does the Mercedes-Benz C300 have bad engine?
The Mercedes-Benz C300 model years with the most engine complaints are 2015 (128 complaints), 2016 (95 complaints) and 2017 (79 complaints).
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