I had my dpf filter changed about 2 weeks ago since I had it changed there has been a huge amount of smoke coming out the back end and it smells of poison! After driving it for about 30minutes the engine service light comes on and that almost instantly stops the smoke coming out. Until I stop driving for the day and get it in for next day it starts smoking and then the engine service light comes on and it stops smoking once again, does anyone on this forum know what this may be could it the brain of the van or something else ?