DPF – Diesel Particulate Filters Removal


There are many companies who encourage removal of DPF’s by cutting out the DPF and replacing it with a straight tube and then remapping the DPF so that it is removed from the ECU, we work within the law and discourage anyone from doing so, the onus is on the driver of the vehicle.

There may be another solution of forcing a regeneration process or there could be other issues the best way is to bring the vehicle to us so we can run a full diagnosis to work out the best way forward. A faulty DPF can not only lose the cars performance but will also affect the fuel consumption, the repair must be carried our immediately if the warning light comes on, failure to do so could result in further damage.

What is a Diesel Particulate filter?

A diesel particulate filter (DPF) is a device which looks similar to a catalytic converter and is fitted to modern diesel vehicles, the main function is to filters particulate matter (PM) from the burnt exhaust gases. It does this by trapping solid particles while letting gaseous components escape. This type of filter has been in use for over 20 years, and many variants exist. These filters enable reductions in emissions which help meet European emission standards, improving air quality and thereby health standards.

Regeneration Process

DPFs are a filter and therefore can become blocked, and needs to be emptied of trapped particulate matter regularly. This is done by a process called regeneration, which involves burning the soot to gas at a very high temperature, leaving behind only a very small residue. The Regeneration, must be carried out properly, if not it can lead to a build-up of soot which can affect performance, fuel economy and ultimately lead to expensive repair costs. This has led to some diesel vehicle owners to remove their DPFS. However, DPF removal has both legal and social implications.

Legal requirements and the MOT test

Since February 2014 the inspection of the exhaust system carried out during the MOT test will include a check for the presence of a DPF. A missing DPF, where one was fitted when the vehicle was built, will result in an MOT failure.

It is an offence under the Road vehicles (Construction and Use) Regulations (Regulation 61a(3))1 to use a vehicle which has been modified in such a way that it no longer complies with the air pollutant emissions standards it was designed to meet. Removal of a DPF will almost invariably contravene these requirements, making the vehicle illegal for road use. The potential penalties for failing to comply with Regulation 61a are fines of up to £1,000 for a car or £2,500 for a light goods vehicle.

There are many companies who encourage removal of DPF’s by cutting out the DPF and replacing it with a straight tube and then remapping the DPF so that it is removed from the ECU, we work within the law and discourage anyone from doing so, the onus is on the driver of the vehicle.

There may be another solution of forcing a regeneration process or there could be other issues the best way is to bring the vehicle to us so we can run a full diagnosis to work out the best way forward. A faulty DPF can not only lose the cars performance but will also affect the fuel consumption, the repair must be carried our immediately if the warning light comes on, failure to do so could result in further damage.