|Cutaway image of diesel particulate filter|
The DPF is designed to trap larger soot particles within the filter. As the soot particles build up, the filter requires emptying. The only way to empty the soot is to burn it off at high temperatures - most often when you are driving on a motorway.
If your car is used most often for short journeys, it may not reach the temperatures required to burn off the soot and can lead to a clogged filter.
Some garages have been found to offer a removal of the affected part rather than replacing it as a quick fix; however, a vehicle that is modified in this way no longer meets the emission standards. Not only that, the car owner has now modified the car and must notify the insurer. This modification makes the car illegal and in turn invalidates any insurance cover.
Diesel Particulate Filters and the MOT
Annual MOT tests require an inspection of the condition of the exhaust system and since February 2014, the MOT test includes a check for the presence of a Diesel Particulate Filter if fitted when manufactured. Vehicles will automatically fail the MOT test if a Diesel Particulate Filter which was fitted when manufactured has been removed.
Replacing the removed components and returning the vehicle back to original equipment will be a costly exercise for vehicle owners who took the decision to remove the diesel particulate filter.
It is the car owner's responsibility to ensure this part is in tact.
If you are concerned about your diesel particulate filter, please visit your local Good Garage Scheme member garage for advice.
The Driver and Vehcile Standards Agency (DVSA) say...
The DVSA is aware of an increasing number of businesses offering a service to remove or bypass the DPF. This practice compromises the MOT testing standards and therefore undermines the principle of inspecting their presence.
Authorised Examiners are responsible to ensure that MOT Testing is carried out to the required standards. Where a Vehicle Testing Station is offering a service which could undermine this (such as removing or bypassing DPFs), DVSA will consider this as bringing the MOT Scheme into disrepute.
Where the scheme is brought into disrepute DVSA may consider taking action to remove the Authorisation if appropriate.