I had this fault on a peugeot derivitive it turned out to be the filler cap for the fluid tank.

I had this fault on a peugeot derivitive it turned out to be the filler cap for the fluid tank.You cannot just blank of the EGR valve on a HDI engine perhaps it needs a new or cleaned EGR or there is the possibility that the matrix is blocked.You need the vehicle putting on a Citroen dianostic macchine I think its called "World "the Peugeot is different and is called "Planet"although the cars are the same mechanically they use a different diagnostic protocol no other system works correctly unfortuneatly.