What Is A Diesel Particulate Filter?

Diesel vehicles produce lots of soot (particulates) that can cause respiratory problems and contribute to the risk of cardiovascular diseases, but since 2009 modern diesel vehicles have all been fitted with a DPF to stop the vast majority of this soot being expelled into the atmosphere. 

No. The great thing about the DPF is that the system is entirely self-cleaning. The process is controlled by the engine management system which combines with pressure and temperature sensors to detect when the filter needs to be cleaned.

When activated, the temperature in the exhaust is raised by multiple fuel injections into the engine, increasing the temperature of the DPF which in turn burns the soot particles to leave just a tiny ash residue.

This whole process takes place periodically without the driver ever noticing that it’s happening.

A DPF should last for well over 100,000 miles, but regular cleaning of the DPF is important if you want to maintain its effectiveness and prevent blockages.

Too many short journeys at lower speeds are the main cause of blocked DPF's because the automated 'self-cleaning' process is only activated when the driver takes the vehicle out on the road for at least 15 minutes at speeds over 40mph.

If the DPF in a vehicle starts to get blocked an orange warning light will typically appear on the dashboard (check your handbook for more information).

Don't ignore a warning light. If the DPF warning light appears on your vehicle driving it for over 15 minutes at over 40mph should activate cleaning process and the warning light will automatically switch off.

If you don't, it's possible your vehicle will go into ‘restricted performance mode’ to prevent any further damage.

If the warning light stays on after you've taken your Motability vehicle out for a longer drive we recommend you contact your local Motability-accredited car dealership for advice. They may need to carry out a manual or ‘forced’ filter regeneration or, in some cases they may have to replace the DPF completely.

Search Diesel Motability Cars