For those guys who are having a problem with check engine light on ,the will be codes which tell you that your sensors ,and or you need to change your valves on the valve housing which becomes an evap problem . Just change your Regeneration valve from the trotter body and your headaches just ends. Stop talking about codes which you don't know about ok,you don't do what I am saying here and you windup doing something different,I don't want to hear about it. The dealers can't tell me nothing I have my car for 15 yrs and I have a good idea about this boxster 2001 .