2020 Mercedes-Benz C 300 Driver assistance Problems

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 NHTSA Hotline to report the failure. The failure mileage was approximately 100,000.

NHTSA ID

11731613

Incident

Apr 16, 2026

Mileage

100,000 mi

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.

NHTSA ID

11710171

Incident

Jan 10, 2026

The component that failed was the fuel injector and spark plug. A few months prior to this incident, I was making a left hand turn, when the accelerator completely gave out. I was making the left on a blinking yellow arrow, luckily the on coming car was not coming at me fast or I would've been in an accident due to the accelerator failing. I had to pull over, turn the car off and then back on to reset it. I was told by the dealership service center that they could not find anything and that there have been no complaints or recalls. After about 8 months of owning the vehicle, it started to have problems turning over when the engine on/off button was pressed. I was repeatedly told that they could not do anything if it did not happen in the dealership service center. This past week on 10/20/2022, while I was driving down the freeway, when I went to accelerate and at that moment the vehicle began to stutter/shake uncontrollably. After that, any time the accelerator was pressed it would shutter/shake. My vehicle was towed to a dealership. Come to find out, cylinder one was coding. They found out that the fuel injector was stuck open. According to the service advisor, that issue was causing a misfire. I was told that they replaced the fuel injector and the spark plug. According to the vehicle report I was given, 1 reman injector, 4 TS spring F In, 1 spark plug, and there was a core return (not sure what that means). The check engine light came on right away. In addition to the incidents above, I have had the forward collision alert come on when nothing is in front of me. I worry that one day it will cause my vehicle to engage the brakes when nothing is around.

NHTSA ID

11490902

Incident

Oct 20, 2022

The contact owns a 2020 Mercedes-Benz C300. The contact was reversing out of her driveway at 3 MPH, the contact was using her rearview camera. The contact stated that the image froze and she crashed into a parked vehicle with the rear passenger side bumper of her vehicle. The contacts bumper was scratched and dented. The other vehicle had sustained a large dent in the driver’s side door. The contact stated no warning light was illuminated. The contact had taken the vehicle to a local repair and not a dealer or an independent mechanic. The vehicle had been repaired cosmetically. The manufacturer had not been informed of the failure. The contact had received the manufacturer recall letter and related the accident to NHTSA Campaign Number: 22V232000 (Back Over Prevention). The failure mileage was approximately 6500.

NHTSA ID

11475739

Incident

Jul 6, 2022

Mileage

6,500 mi

The contact owns a 2020 Mercedes-Benz C300. The contact stated that suddenly the vehicle's sensors were illuminating and activating a warning stated that the sensors were defective. Many of the vehicle's sensors began to deactivate and malfunction. While reversing out of a parking space the rear view camera and sensor system failed causing the contact to crash into another vehicle. Both vehicles were damaged. A police report was filed. There were no injuries reported. The vehicle was not towed. The contact took the vehicle to a repair facility and stated that there was damage to the internal sensor and camera system. The contact took the vehicle to the dealer however the vehicle had not been diagnosed or repaired as of yet. The contact then received a recall notice NHTSA Campaign Number: 22V232000 (BACK OVER PREVENTION) however the VIN tool confirms remedy not yet available. The manufacturer was not made aware of the failure. The approximate failure mileage was 3,000.

NHTSA ID

11469155

Incident

Apr 8, 2022

Mileage

3,000 mi

Automatic emergency braking system & forward collision warning. I experienced a medical emergency and blacked out, hitting 3 cars. The incident happened the morning of Dec. 31, 2021 and my car still has not been evaluated by Mercedes. I was taken to the ER and spent 3 days in the hospital.

NHTSA ID

11452817

Incident

Dec 31, 2021

ON A NUMBER OF OCCASIONS, I HAVE RECEIVED AN AUDITABLE WARNING, AND A RED LIGHT ON THE DASH THAT DISAPPEARS AS QUICKLY AS IT HAPPENS. I CANNOT CONTRIBUTE ANY CAUSE FOR THE WARNING AND THERE ISN'T ANY RESIDUAL INFORMATION ABOUT THE SOURCE OF THE WARNING.

NHTSA ID

11385957

Incident

Dec 31, 2020

Mileage

1,000 mi

TL* THE CONTACT OWNS A 2020 MERCEDES BENZ C300. THE CONTACT STATED THAT WHILE DRIVING AT A HIGH RATE OF SPEED, THE VEHICLE WOULD ABRUPTLY SLOW DOWN ONCE THE TRAFFIC SIGN READER FEATURE ACTIVATED INDEPENDENTLY WITHOUT WARNING. THE CONTACT STATED THAT ONCE A TRAFFIC SIGN ON THE ROAD WOULD INDICATE A CERTAIN SPEED LIMIT, THE VEHICLE WOULD THE SPEED LIMIT SIGN AND AUTOMATICALLY ADJUST THE VEHICLE'S SPEED TO THE SPEED LIMIT READING. THE CONTACT INITIALLY CALLED MERCEDES-BENZ OF BONITA SPRINGS(14610 TAMIAMI TRAIL N, NAPLES, FL 34110) WHERE HE WAS INFORMED TO CALL THE MANUFACTURER. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE AND THE CONTACT WAS INFORMED THAT THE TRAFFIC SIGN READER FEATURE COULD BE DEACTIVATED ON THE VEHICLE. THE REPRESENTATIVE WALKED THE CONTACT THROUGH THE STEPS TO HAVE THE FEATURE DISABLED. THE CONTACT STATED THAT HE WAS NOT THOROUGHLY MADE AWARE OF HOW THE FEATURE PRIOR TO PURCHASING THE VEHICLE; HE STATED THAT THIS FEATURE COULD LEAD TO A SERIOUS CRASH OR INJURY. THE FAILURE MILEAGE WAS APPROXIMATELY 12,000.

NHTSA ID

11339325

Incident

Jul 10, 2020

Mileage

12,000 mi