DPF Blocked

There are quite a number of faults that can lead to premature DPF blockage , here are a few

If the wrong engine oil is used it can cause a severe shortening of the DPF lifespan ,This can be caused as most vehicles with DPF filters use a low ash oil

If the vehicle is only used on short journeys and dosnt have a chance to get hot ,The DPF filter will not get to a self generating heat and cant clean itself

If the vehicle is used on short trips the vehicle ECU dosnt get a chance to do an active regeneration (this is where the vehicle ECU takes over and does a controlled burn to get the tempreture of the DPF up to the correct tempreture) 

The injectors could be atomizing badly causing incomplete combustion

The MAF or (Mass Airflow Sensor ) could be faulty  

One or more of the DPF sensors could be faulty

So as you can see there are quite a few reasons for  a blocked DPF filter , once it is cleaned make sure you know what  the cause of the blockage was and rectify it , otherwise you could be in for a repeat failure