Hi guys I know this topic may have been discussed before but I searched and havent found anything on it yet. My Check engine light came on about two months ago. I have been driving it and nothing has happened yet "knock on wood". But I had my friend check the code and it read 67 catalst system efficiency below threshold. What does this mean although I am thinking it has something to do with catalytic converter I am not sure so help is highly recommended. Is there a real high threat to worry about?

 

Either the o2 sensor on the cat is bad or your cat is probably bad.