According to foreign media reports, the National Highway Traffic Safety Administration (NHTSA) has put pressure on electric vehicle manufacturer Tesla and conducted 11 car recalls in the United States in more than three months. Elon Musk, CEO of the company, is obviously dissatisfied with this p> < p > < / P > < p > when a twitter fan asked Tesla on Saturday about the reasons behind the recall of more than 500000 cars due to the automatic speaker function Boombox, musk replied: "it was the disappointing ghost that made us do this (sigh)." Tesla launched the Boombox function in 2020, which allows drivers to play preset or customized sounds, such as goat barking or farting, through the external speaker when the vehicle is driving p> < p > last week, Tesla informed NHTSA that in order to meet the safety standard of electric vehicles warning pedestrians, the company would disable Boombox when the vehicle is driving, in neutral or reversing. The company said in its recall report that NHTSA requested information in January 2021 to investigate whether the function met safety standards. After several months of voluntary consultation with Tesla, the agency decided to recall p> < p > NHTSA indicated that Boombox may prevent pedestrians from hearing mandatory warning sounds, thus increasing the risk of collision. All electric and hybrid vehicles need pedestrian warning because electric vehicles are quieter than internal combustion engines p> < p > this is Tesla's fourth car recall in two weeks. The number of cars recalled this time is 578607. Tesla will release firmware to disable the Boombox function in drive, neutral and reverse modes p> < p > affected vehicles include model s, model x, model y in 2020-2022 and some model 3 in 2017-2022. NHTSA said in its safety recall report that the agency received complaints in January 2021 and has been investigating them because Tesla is "further demonstrating and defending these tests" p> < p > last week, Tesla recalled 817143 cars because if the driver's seat belt is loosened, the warning sound will keep ringing. Prior to this, the company recalled its "fully automatic driving" (FSD) software, which could not recognize stop signs in some cases p> < p > at the same time, Tesla's driver assistance driving system autopilot and its on-board video game function have also been reviewed by NHTSA p> < p > NHTSA's action shows that the regulatory authorities are strengthening the technical review of Tesla. Musk had previously said that these technologies played a key role in Tesla's becoming the world's most valuable carmaker. Last September, he said on twitter that investors had "highly praised" the company's autonomous driving ability. (small) < / P > < p >