Replace the Diesel Particulate Filter

[Scottish Scrutineer]

Get a second opinion from a VW independent garage, if this is the third time around it’s in for repair then it sounds like they are guessing.
VW use Pierburg EGR units in many cases, if you buy a Pierburg you are effectively getting the same part.
No idea about DPF, be ware of non OEM parts that have been re-worked, if the MOT tester suspects it’s not complete then it may fail.

@P4M , this advice from @DXX is spot on. It sounds like the garage are just replacing parts and hoping that they stumble across the fault cause. Lots of VW Specialists about who should be able to get to the bottom of the problem.
Another consideration is the type of journeys that you do. Euro 6 vehicles don't do well with repeated short trips when they don't get fully up to temperature and run for long enough as compete DPF regenerations. Avoid supermarket fuels if possible and use a decent fuel additive if you can.

 

[Bigsidavies]

Would the only reason it won’t start, if the issue is DPF, because the dpf is blocked?
Is it not possible just to remove it and see if the van starts? Or is it not that simple?