2.4JTD desired boost

[stevesportwagon]

Hi all,
I've just connected to my Alfa 156 and cleared the fault codes, I looked at some parameters while I was there as I thought it was overboosting, but the desired boost value stays at zero whether at idle or full throttle! surely this should fluctuate with engine revs and throttle opening?
The actual seems to read correctly at around 1000mb at idle rising to 1700mb when flooring the throttle at a stanstill - I'd of expected the desried to be similar to this, is this a bug? where does the desired value come from- car ECU or generated from the scan program?
Any help would be appreciated.
Regards Steve