I can't find a solution to this problem. Today, I took a black n18 valve (which the tab isn't white) out of a Beetle (tdi) to replace the one I have in my 2003 Jetta (tdi) with a code of P0401 because I wanted to see if it would solve the problem but unfortunately, it didn't. Therefore, I have the EGR and the intake manifold cleaned out. So what should I do? * Should be n239 valve bad?