I have a 2007 Volvo S40 D5 auto. Head was replaced by Volvo technetian 8 months ago. Injectors was refurbished. Al of a sudden Car showed "shooth filter blocked" They replaced the DPF filter after trying to bypass it with mini cats. The ECU was cleared and new software loaded, still the same message and then going into limp mode. What else can be wrong?

 

I assume your "shooth filter" is Google auto-correct speak for "soot filter". I'd start by having the car scanned for all fault codes using an OBD2 code reader. Next is to read up on some prior posts on soot filter issues. Note the UK forum will have more posts/content related to oil burners. Here's a good link to start with:

https://www.volvoforums.org.uk/showthread.php?t=264612