Hi i need bit help my car is running fine but there is engine light on and code reading p2440 any ideas what the problem could be 

I took it into a garage for  new alternator and it came back with this engine fault light on the garage i took it to was a small back street garage and didnt know what the code means as only has small code reader so took it to another garage and they reckon the dpf filter is totally blocked but im not so sure as its running fine any help would be much appriciated thanks Ian 

P2440 is a red herring I think.  It doesn't apply to diesels.

You'll need to get some Ford specific diagnostics on it, Forscan is ideal for a DIYer.  It's probably worth checking that there aren't any lose plugs around the alternator that might have been knocked.

Thanks for your reply tomsfocus ill check for loose plugs or damged wires as there was no warning light on when took it in for alternator 

has anyone tried clearing the code to turn light off, then see if the light comes back on again, if it does re-read the codes.

good fault code reader less than £20, these can also clear codes, not just read them.  Use with a laptop or (smart) mobile phone.

Good software is Forscan which is free for Windows and about 6 quid for Apple/Android.

There is other software for phones which is free, not as good as Forscan but still useful.

It is a small investment for being able to check stuff yourself. And even if you can't do any work yourself it's useful to check if the garage is bull****ting you.