dumb question -removing lower hose on intercooler

I have had a fouling of the air sensor at the top of the intercooler, triggering a CEL light and P026A code. It was suggested to remove the large rubber hose at the bottom of the intercooler to clean up and remove any accumulated oil/sludge that might be contributing to the fouling.

I dropped the plastic belly pan and completely loosened the clamp (or so I thought) and the hose is really tightly bound to the intercooler flange. Is there a trick to loosing this clamp so that the hose can slide off easily? Is there more to the clamp than just loosening the nut?

The rubber hose on the plastic flange will glue itself in place after a few years. I use a cotter pin removal tool (looks like an awl with a bent end) to slide between the hose and flange to break it free. finding a little sludge is normal.

Thanks, will try that soon.

FWIW, this issue is with my 2013 Passat, not the '05. Originally posted in the B7/NMS forum, moderators moved this thread to this forum by accident.

My '05 has never had a CEL thrown in now 13 1/2 years, no issues with sludge or bad sensors.