Code 4530 - testing pressure converters?

[Ohsoslow]

Hey guys, 2010 x5 40d, have been getting “reduced power” warning popping up on dash briefly when going up hill at around 1500-2000rpm, most of the time with no noticeable loss in power. And some days it doesn’t do it at all.

My searching has come up with boost leaks, vacuum hoses, and pressure converters, being the 3 main culprits. How do I go about testing the pressure converters? There is two different styles I can see, I have a vacuum gauge, and the one style when I put vacuum into the inlet port, they hold vacuum, the other style, I can’t get to hold any sort of vacuum.. which is possibly the cause of my problem, but can’t find any info at all on testing procedures.. part number for that pressure converter is 11658509323.

Thanks for any help!