DPF Removal

What is a DPF?

The vast majority of people do not know what a DPF is, or even that their car is fitted with one until it costs them a lot of money. A DPF (Diesel Particulate Filter) is a device fitted into the exhaust system of all new Diesel cars since 2009. Its purpose is to reduce emissions being emitted by the vehicle, with emissions laws and regulations becoming increasingly strict.

The DPF catches diesel particles produced during the combustion process and then expels them as ash when the vehicle goes through a regeneration cycle. The problem arises when these regeneration cycles cannot be carried out and the DPF becomes blocked, which will put a warning light on your instrument cluster. If driven with a blocked filter, you can cause other costly problems with other components. The extra backpressure because of the blocked filter can very quickly cause damage to the turbo.

There are a number of reasons that DPFs can become blocked. One of which can be down to the types of journeys the car is used for. The DPF requires certain conditions to carry out a successful regeneration and if it is doing constant stop-start and town driving, the regeneration cannot be carried out, leading to a blocked filter. It can also be caused by a mechanical problem such as a faulty EGR valve, turbocharger or injectors, so if you’re considering having a new DPF fitted at many hundred of pounds, its worth getting the car checked too. Otherwise you may find yourself in the same position very quickly!

Blocked Diesel Particulate Filter

DPF welded shut after being hollowed

DPF Warning Light on Dashboard

Why remove the DPF?

DPF removal is not for everybody. Here are some of the reasons for removing the system…

– If the DPF is already blocked, replacing it can cost upwards of £1000 and dependant on your journeys and driving style, it could block again. Our DPF Removal Solutions generally cost less than half of that and can’t block up again.

– When increasing power, DPFs limit what you can do with fuelling. So if you are after maximum performance from your car, DPF removal will give me freedom for fuelling changes.


Now, there are also some things that we would need to make you aware of before removing the system.

It is a legal requirement that any car that was fitted with a DPF from factory, has to have it fitted to pass through the MOT process.

“Garages and testing stations will be required check for a diesel particulate filter (DPF) in the inspection of the exhaust system as part of the MOT test (or annual test for heavy vehicles) from February 2014.

A missing DPF, where one was fitted when the vehicle was built, will result in an MoT failure. A vehicle might still pass the MoT visible smoke emissions test, which is primarily intended to identify vehicles that are in a very poor state of repair, whilst emitting illegal and harmful levels of fine exhaust particulate. 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.

The vehicle will automatically fail the MOT test if the filter had been fitted as standard but is found to be no longer present.

At the moment, it is only a visual inspection, and after our service has been carried out, it will not look like it has been tampered with. However, whilst these laws are the curent laws, in the future they may be changed to monitor diesel particulates in the exhaust gasses. This would highlight that the DPF has been removed.