partical filter light?

can someone please tell if the partical filter light should come on when i start the engine because i had a problem with this light coming on in my renault megane 1.9 dci also a mesage came up on the dashboard saying check injection i took my car to the show i bought it from i got the car back but it still says i have a injection fault so i am thinking that the garage has just disconnected the partical filter warning light any help on this matter would be appreciated
thanks