I got that message on starting up,and the little warning symbol on the screen.
However the car runs fine,and the message disappeared almost immediately,although the warning symbol remained.
I added a bottle of Wynn's DPF cleaner to the tank,and,remembering a tip from my previous Vauxhall,disconnected the battery,to reset the ECU.
The warnings have disappeared,so fingers crossed!
My Citroen 07 C4 Picasso 1.6 hdi VTR,has onlt done 44000 miles,and goes well,so I don't think there's much wrong!