Fault code 4bc3dde exhaust gas temperature not present. What part do I replace?

Hello, this is a question that is beyond the advice that can be given in this forum. You need a technician with experience that specializes with BMW Diesel performance issues. This is not something that your conventional, normal auto technician would be able to approach with any kind of knowledge. https://repairpal.com/repair-shops/bmw-repair-and-service-in-jackson-heights-new-york

There is usually more than 1 temp sensor for that system that’s where you would need to start. They are basically before and after the cat converter and another after the dpf you need to find out what one is the reason for the warning and test from there