The light will be there somewhere but it won't actually come on unless you have an issue in which case if it's anything like the VW's it will probably put the car into LIMP mode which would then require a very slow trip to the dealer for repair :( The DPF itself should be just after the turbo as they need to be as close as possible to the hottest part of the exhaust to be able to get the temperature hot enough to do their regeneration (burning out the crap) The biggest problem with the DPF's is that as they stop a very high amount of the soot from escaping and therefore they restrict the flow as well, a lot of this carbon build up ends up in the manifold and associated areas and eventually clogs to the degree that it needs to be physically removed and cleaned out :( There have been quite a few posts about it on one of the VW forums I used to post on (when I had my TDI Golf) before buying the Focus
