What 33 owners told NHTSA about the 2021 Mercedes-benz S-class Phev

Driving on highway at about 50 mph when the brakes suddenly slammed on and brought car to a sudden, near stop. The stop was so sudden our seatbelts engaged and we thought we were struck in the rear by another car. Electrical module issues that cause battery to drain while vehicle is turned off have been ongoing since I purchased the car in October, 2021. Car has been in for service related to this problem 6 times and for over 60 days.

NHTSA ODI 11501439

The contact owns a 2021 Mercedes-Benz S580. The contact stated while driving approximately 5 MPH, the brakes failed to function as needed while the brake pedal was being depressed. The failure resulted in a crash. There were no injuries sustained. The contact stated that the accident occurred due to the failure in the braking system as well as the intelligent driving feature. The contact stated that the vehicle inadvertently shutoff and restarted without driving input. The brake assist feature did not engage because the driver was already actively depressing the brake pedal. The contact stated no warning light was illuminated. The vehicle was taken to a local dealer where it was test-driven for two miles however, the contact was yet to receive any information on a possible cause for the failure. The contact was concerned that it was only a matter of time before an even more serious accident would occur. A police report was not filed. The manufacturer was contacted, and the contact requested to be provided the diagnostic report, the Event Data Recorder (EDR) info, and the front camera info. The contact was informed that if she provided any videos or subsequent pictures prior to the crash, she would be provided the information that she requested. The contact later received a letter stating that she would not be provided the information requested. The contact was provided with no further assistance. The vehicle was not repaired. The failure mileage was approximately 1,194.

NHTSA ODI 11444036