Essentially it means that your Diesel Particulate Filter has accumulated too much soot and ash, and occurs almost exclusively when it cannot regenerate itself and therefore logs the error.

If you’re unsure of how the DPF Filter system works, check out our full blog here:

This is very much dependent on the car you have and specifically how the sensors and regeneration systems work on your particular car, but there are some generic things that you should know.
A DPF should be able to regenerate on its own:

In a great working system, a DPF should be able to regenerate itself. You’ll only experience these issues when either the engine is now inefficient (and producing too much soot even during regeneration) or you’ve had some sort of contamination resulting in ash build up (cannot be burnt off in a regeneration process.

SO – until you’ve found your root cause, there’s no real point in spending money on the DPF.

Deeper understanding of your system!
The ECU cannot physically tell the situation with the DPF. Therefore it uses a range of sensors to establish an idea of what is happening. This fault code is almost always