Mitsubishi Repair: Service Engine Soon Light, service engine soon light, happy new year

Question
Went to advance auto and got the code P4021 says warm up catalyst do i need another manifold or is the sensor gone bad ? Thanks

Answer
William: If the code showed a code number such as P4021 then I would get the sensor in the catalyst. But don't know what engine you have, what car you have, model or make. But you need to take your car to a shop and get them to fix this problem for you. If nothing else buy a repair manual for your car, it would explain how to fix this, walk you through explaining how it is done and it uses pitures too. Haynes is a good one to get. I do hope this helps and Happy New Year! Linda