A total of 817,143 Tesla electric cars were recalled due to a software issue that could prevent the seat belt alert system from sounding when not properly installed.
This reminder system works when the car is traveling at a speed of 22 kph. An alarm will sound when the seat belt is not properly attached. And, according to FMVSS 208, S7.3(a)-(1), all vehicles are required to have an audible seat belt reminder when the vehicle starts to move.
Software errors only occur under certain circumstances. According to the NHTSA document, when the buzzer was interrupted in the previous drive cycle and the seat belt did not flex after the disturbance.
Neither NHTSA nor Tesla have received any reports of any injuries related to this error. However, this error was first noted by the South Korean Institute of Automobile Testing and Research on January 6, 2022, which caught Tesla's attention.
Meanwhile, the Tesla team has investigated the matter, and they have determined non-compliance and determined that a recall is required.
Tesla has released a firmware update to fix this issue. The update is available to Tesla Model 3 and Y owners on January 27, while for Tesla Model S and X on January 28.