Tesla announced a recall of 11,704 Tesla cars that included Model S, Model X, Model 3, and Model Y. The vehicles recalled all had something in common. They were vehicles operating the firmware release 2021.36.5.2. Tesla explained that a software communication error could, " under a certain sequence of events, " trigger a false forward-collision warning and activate the emergency breaks. The event caught the attention of the federal agency, National Transportation Safety Board NTSB — already investigating Tesla over a series of incidents where Tesla cars crashed into police vehicles.