Quick update.. Yes the exhaust brake needs to be adjusted with the DX2 software. Look to see if you can monitor "injection Quantity" with your snap on scanner. I could assist with a work around possibly if you can view this data. The unit would also have to be equipped with a high idle knob, or have the ability to use the cruise control to bump the idle to 980 rpm. The unit would need to be at 980 rpms when checking injection quantity. The exhaust brake is not as effective as an engine brake, or "Jake brake". If you adjust it too much it can make it worse. When performing a manual regen it relies on the exhaust brake to generate the heat more so than when driving. So it will complete a regen, has no codes and no bars on the DPR gauge? When you say "some soot" can you be more specific? Any soot in the tailpipe indicates a DPR that is breached or cracked. Report back with findings and I can be of more assistance.