Question for volvo techs!

Look for crack in a barrel. Take shield off and you will see. Have welder fix it.
System cannot build pressure enough to have process complete proprly

 

Cold air leaking in doesnt mix too well with hi temp regen.Check clamps,rubber hose,cracks etc

 

most likely your flex pipe has failed the asbestos is in the dpf plugging it up causing it to get hot , that the most common failure , and also if the turbo boost is over 10 psi when it doing a regen some time the regen will get to hot , on the dpf you will see a tube that gos the dpf pressure sensor and there is a temp next to it if you remove both of them and use a flash light in the temp sensor hole and look in the tube hole you can see inside the filter just enough to so if a looks plugged ,if not the only way is to pull dpf apart . you can reuse clamps ,just replace gaskets