Problem with 06 VW Passat 1.9 tdi
 

Guys, car seems to have lost turbo power, sometimes when turn it off and on it comes back but there is a light up on dash which says emissions, mechanic in one garage reckons its the turbo but other reckons its not as its not heavy on diesel or throwing out black smoke so cud be "whist...." cant rem full name of it, anybody got any ideas? somebody else said it might be the EGS valve? cheers