my mondeo 2008 2.0 edge diesel has come up with an amber engine management light plugged it in and says the following P2002 powertrain particulate trap efficiency below threshold bank 1, I drive up and down the m4 each day doing about 70 miles in total any ideas would be great I've tried driving it in a low gear at 70 but this doesn't clear it as I've seen some suggestions that that may clear it.

Eventually all DPF's block up with ash residue, which is left behind after burning the soot at each regen.  I wouldn't be at all surprised it that was the case on a 2008 model. 

If it is blocked with ash, the DPF needs to be removed and either professionally cleaned (must be backflushed from the bottom, the ash will not go through the DPF core) or just replaced with another one.

You can try an external DPF cleaner, sprayed directly into the DPF through a pipe or sensor hole, but that only works to breaks down soot, it will not work for ash.

5 minutes ago, TomsFocus said:

You can try an external DPF cleaner, sprayed directly into the DPF through a pipe or sensor hole,

......and guess what job I'm doing this Saturday morning 🙁 Must admit not looking forward to it encase it makes the situation worse.