Well this thread has caused me look harder at the EGR operation than I have had to for a long time
There was something else in the Lexia traces that had me going WTFIT! so dug out the Bosch description of the system a copy of which I sent you and after a little perusal I remembered something that I last had a look at at about 6 years ago !
On the front of the Inlet Manifold there is a Y shaped bit of manifolding and in each arm of the Y there is a butterfly valve (vac controlled via an EV) now one leg goes to the O/P of Intercooler (cold air) and the other goes effectively to the I/P of the intercooler (hot air). Now it was my understanding that when the engine was cold the butterfly were modulated such that the inlet air temp was kept high for quicker warming up. However it would appear that they also play a part in the EGR circuit as well quite how or why I hav'nt got my head around yet but look at the EGR description in the Bosch HD152C doc I sent you.
When looking at the EGR Lexia trace you can see that up to the 70 second mark the Exhaust gas Recycling THROTTLE EV open cycle ration is about 50 % what 50% means I am not exactly sure but my belief is that it means that the PWM of the EV is equivalent to 50 % valve open.then we can see it goes max open at about the same time as the fuel flow is increased, presumably acceleration, from there on it bangs about between max open and shut, this valve is the cold air inlet to the manifold. The interesting thing about this is that it stays in step with turbo pressure which seems to change in steps. Now ask yourself what happens to turbo pressure if the inlet manifold is blocked? the pressure will rise. Unfortunately we don't have a trace for the other manifold valve to see if that is opening and closing in step if it is not then effectively the inlet manifold could be being blocked, however measured airflow would tend to suggest that this is not the case. We would be able to deduce more if we had either accel; position or rpm as a master trace.
The two manifold valves like the EGR are all driven by vac via EV and PWM and like the EGR there is no way of knowing from the Lexia if they are actually doing what they should!
For testing these valves Citroen / Facom have a very nice tool which has a built in vac pump and gauge, undoubtedly expensive! To test them the Lexia has a menu line Actuators under the same heading as Parameters but you still need a vacuum, you can get this by running the engine or plumbing in an external vacuum source if you have one, The noise from the engine can make it difficult to hear the click from the EV's and the EGR but i managed! The two butterfly valves can be visually inspected if required by taking off the rubber hoses and using a mirror or even ones fingers !
From this lexia traces as far as can be judged the MAF looks good in general terms i.e turbo pressure increases flow increases and the turbo pressure matches the reference pressure, however this doesn't mean that baseline MAF o/p is correct, it would be nice to know what the value should be at idle.