Stig,

I had a P0410 on my S320, and the emission components are similar in other models. I had a leak in the control vacuum for the air injection control valve, and the leak came from this little rubber female wye vacuum fitting that tapped into manifold vacuum near the throttle body.

In looking at post 18 picture the air injection is still controlled by vacuum. Follow the vacuum control line, and somewhere down the line is solenoid that controls the vacuum to air injection valve, and beyond the solenoid vacuum line check the line to the vacuum source. Very near the source is rubber wye that just gums-up and turns into in marshmallow. Check the line. See what the outcome is.

On my S320 the EGR was the same, but I believe on 2000's and above the EGR's are electronic

Check that out, and see where that takes you.

Best of luck,

Martin