你是啥车？以前帮助修过一个老Infiniti V6是管子赌了，换了管子，顺便换了EGR Valve，便宜，就修好了

https://www.700r4transmissionhq.com/p0401-toyota-camry/#:~:text=P0401%20is%20a%20common%20OBDII%20trouble%20code%20that%E2%80%99ll,three%20main%20parts%20of%20the%20Camry%E2%80%99s%20EGR%20system.