Hello snap ,most times you can just skip through like you say and get to egr and actuate it , I've always found vcds is good for activations and puts up all relevant data blocks that's involved with whatever your testing......but no worries , just put air mass data block up , remove vac pipe off egr , if you have a length of vac pipe just just put it on the egr vaccum pod and suck on it with your mouth ( oooeerrr missus ) and look for air mass drop .
Sounds like the vac leaks was the issues though if now it's not logging codes .
Where you say about actual air mass being more than desired .....is that the case now that you have sorted the vac leak to the egr .
I've found if you leave the engine idling for a time egr normally turns off ( so closed valve ) just a blip of throttle brings egr back in so then you get the lower air mass reading .
Egr switches off at idle for a process called 'smoke limitation ' ...... bleeding exhaust gases in at idle makes the combustion suffer .
Egr is an inert gas ( does not support combustion ) if you watch what egr does in data blocks when driving you will see it opens the most on lite throttle loads .
Light throttle loads makes combustion temp go high ...... high combustion temps makes NOX gases ....hence bleed in inert gas to lower burn temps ........ what happens when gas burn temps are lower ....... soot particles produced ...... hence dpfs came along .
I'm going off on a tangent here arnt i hehe
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