P0406 How to?
 

My daughters 2008 Escape with a 3.0 and 186K is throwing a P0406. I don't have a service manual or diagram. We shotgunned the EGR valve and DPFE. Still no luck. Does anyone know of an actual troubleshooting procedure, or diagram ? Emissions testing looms in June! BTW this is the same car I posted about in 2017 https://www.fordforum.com/forum/ford...tch-out-36563/