I am getting the same code 44. But my CEL is on. Did you get yours corrected?
I've checked and replaced all of the vacuum lines going to the TAB, TAD, FPR, EGR valves so I don't think that I have any vacuum leaks.
I know that the TAB valve works properly because it's dumping air through it when I do the KOER test. I haven't checked the TAD valve or check valves yet due to the location of these but that's next on the list.