ISB 6.7 crankcase pressure fault code

[Ryda]

Hello everyone, new to the forum, and I operate a straight truck as opposed to a tractor. I have a 2012 frtlnr with the cummins isb 6.7. Purchased a year ago with 137,000(or so) miles and currently at 223,000. There's a back story to this problem but it is very detailed.......current issue is fault code spn 101 on the dash, can't recall what the code is in insite. I recently cleaned up my egr valve and cooler, replaced oil cooler as a result of oil in reservoir. Prior to this I did replace the Crankcase breather filter and the crankcase pressure sensor because the same code was popping up before, but went away after the filter and sensor were replaced, and resurfaced after cleaning out the egr cooler. It happens in hilly terrains mainly, (side note, I replaced the fan clutch because it was extremely loud and the truck would seem to be under a load as soon as I take of, empty or loaded). Had regen issues prior, but rectified those by cleaning egr valve and replacing associated sensors in december last year (thanks Rawze). Did a reclean on egr valve when cleaning egr cooler last month. When performing stationary regen, I notice my turbo speed doesn't get above 28,000rpm. I'm wondering if since cleaing the egr cooler(this was completely plugged up and took two soakings with the egr cooler cleaner, and a power washer after the second soaking to get it clean), the increased air flow has anything to do with the crankcase pressure code. I believe there is a deeper issue, don't know where to start, except I believe my problem may be with air intake........I don't have extensive knowledge of the airflow system and all components involved with it and how they impact each other.......also wondering if air compressor could be a contributor.....thanks in advance for any help that can be provided.