[Piwoslaw]

Originally Posted by euromodder

Hägar reportedly has an issue with excessive EGR - though the EGR-valve has already been replaced under warranty early in its life to (not) cure a bucking problem while regenerating the DPF.

Too much EGR will also reduce power on partial load, which is what I felt right away, and what I've been seeing on slight inclines where Hägar dumps in far more extra fuel than the S40 - wether it's on CC or not.
Snert responds a lot better to switching off the CC uphill as well.

I just found a research paper which claims that too much EGR in a diesel will lower exhaust temperatures, resulting in lower NOx but also increased PM. This may explain why your DPF kept going into regen. My guess is that this should have shown up on emissions tests as the NOx would have been lower than usual, though nobody would have known. Also (not sure about this), the EGR valve may have a feedback signal as to how 'open' it is, allowing the ECU to compensate, and allowing the diagnostic to notice that something is wrong. On the other hand, the ECU may be sending a faulty signal to the EGR valve, making it open too much. So much for my armchair diagnostics

I'm paying close attention, since this may effect my engine also, though without the FAP problems. I do hope that they get this permanently sorted out so that you can start getting Snert-ish milage