cosworth

I have bought a Lexus IS 220D 2006 few months ago. I have read a lot of posts in different forums and I decided to check the status of my EGR valve even I did not feel that smth is wrong with it. I unscrewed the pipe which is placed on the top of EGR and got a surprise. There were a lot of carbon black. Look a few movies on youtube how to clean it (the same wich is posted in 1 page of this topic). I bought an EGR cleaner which helped a lots and with crewdriver help cleaned everything well. After it I cleaned air intake hole, which connects EGR bottom part and a few carbon parts were droped inside of the hole. EGR valve and that intake part now looks fine. I connected everything back in same places, wires as well. And tried to strat engine. After a few long tryings engine starts and suddenly it shuts down. I waited for a while and tried again. Luckelly engine started work, but the story did not stop here. At the same night for an half an hour driving outside city I got "Check VSC" warning message and car went into limp mode. I understood that smth wrong. After scaning it showed Exhaust gas recirculation (EGR) P0400 error code. Any ideas why it went wrong? Maybe I missed smth? I decided to replace EGR and one of mechanics mentioned that if I change it by mayself it would not work, because need to do smth for heating or etc. I would appreciate if anyone could post step by step what I should do if I want to change my EGR.