There are 6 owner-reported driver assist & adas complaints for the 2023 Mercedes-Benz C-Classin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
The contact owns a 2023 Mercedes-Benz C300. The contact stated that on occasion while driving at various speeds, the vehicle unexpectedly stopped without the brake pedal being depressed. There were no warning lights illuminated. The vehicle was diagnosed twice by the local dealer, and the contact was advised that the Forward Collision Avoidance sensors needed to be recalibrated; however, the failure persisted. The vehicle was taken back to the same dealer where the vehicle was inspected, and the contact was advised that further diagnostic tests were required to determine the cause of the failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 28,000. The VIN was not available.
Filing complaint on behalf of my sister. She was driving on empty side street around 25mph and the car comes to an abrupt stop. Apparently part of the collision avoidance system, yet nothing in road, on road or in sight. If there was anyone behind her, they would have slammed into the rear end of her car.
Major safety issue - PHANTOM BRAKING. On 2 separate occasions the vehicle engaged emergency braking while there was no apparent hazard. This phantom braking was very dangerous. This car has adaptive cruise control. It occurred in the exact same spot on Interstate-84 and NE 21st Avenue in Portland, Oregon while traveling east bound. The cruise control was on and engaged in incident 1. Cruise control was on, but not set, in the second incident. First incident was approximately 6/1/23. Second incident was 7/16/23. I have reported to Mercedes Benz Customer service. Case opened #2-42097036640. I will contact the dealership to report as well.
The contact owns a 2023 Mercedes-Benz C300. The contact stated that while driving at various speeds, the Forward Collision Avoidance system erroneously activated, causing the vehicle to abruptly stop in the middle of the road. The failure occurred on three separate occasions and each time no other vehicle or object was nearby to cause the Forward Collision Avoidance system to become activated. The vehicle was taken to the local dealer who replaced sensors and recalibrated the Forward Collision Avoidance system, but the failure persisted. The manufacturer was not notified of the failure. The failure mileage was 1,000.
This car has the driver assistance package including Active Speed Limit Assist which is supposed to automatically adjust the speed of the vehicle based on detected speed limits. However, it gets the speed limit wrong an excessive amount of the time sometimes resulting in the car suddenly decelerating which I consider to be a serious safety issue that could result in collisions. In my situation, I have experienced the car suddenly slowing to 40 mph for no reason in an area where the speed limit was 65 mph. I have also seen this problem documented on a number of blogs related to Mercedes-Benz vehicles. When I reported the problem to the dealership, I was told that it was a known issue and was encouraged to turn this feature off. I think Mercedes-Benz needs to fix this known issue for those of us who have cars with Active Speed Limit Assist.
The contact owns a 2023 Mercedes-Benz C300. The contact stated that while driving with the Adaptive Cruise Control engaged, the vehicle decelerated quickly, causing the driver to lose control of the vehicle. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was not made aware of the failure. The failure mileage was unknown.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026