Diesel Particulate Filters (also known as DPF or FAP units) are now fitted to the majority of modern diesel cars, built after 2009 in order to meet increasingly stringent Euro 5 emissions levels, which are in place throughout the UK and Europe. In order to meet these new emissions levels, Diesel Particulate Filters are considered a mandatory fit by most car manufacturers since 2009, and in fact a lot of German, Swedish and French manufacturers have been fitting them to diesel engined vehicles as far back as 2002 in order to get large engined SUV or 4×4 vehicles and those with Automatic gearboxes through Euro 4 emissions standards which were in place at the time, so if you are wishing to avoid the whole DPF fiasco and potential pitfalls entirely, then you should choose your older diesel engined vehicle very carefully and research the model before you buy it, in order to check that the DPF was not already standard fitment or one which was offered as an option, which the previous owner had paid to have.
Unfortunately, DPF problems are very common and they can be very expensive, usually related to blockages or the driving style of the owner and still many dealers are failing to warn the potential owners of modern dpf equipped diesels that they are not suitable for car owners who cover low annual milages (<12000 miles), regular short journeys or urban commuting and that the advice in relation to the diesel particulate filter in the owners’ manual should be followed. The end result of this is that owners are soon finding the DPF blockage warning light is illuminated on the dashboard, or worse still they are required to make an expensive trip to the dealer to have their DPF’s cleaned as part of a dealer based DPF forced regeneration procedure, which is carried out using the cars’ diagnostic system.
In an alarmingly growing number of occasions, the Diesel particulate filters are found to be beyond cleaning and require replacement with a brand new DPF unit, often costing anything between £500 – £2000 depending on the vehicle model and the dealer. At least one well known car manufacturer has stated that the Diesel Particulate Filter on their vehicles is considered a consumable, and so any warranty claims for repair or replacement will not be honoured, should it be found that the car has been used for short journeys or the owner has not followed the advice contained in the owners manual in respect of taking care of their DPF.
This attitude is not unique and has resulted in a lot of people facing huge repair bills for DPF failures on low mileage, relatively new vehicles.
Naturally, when faced with a potential four figure repair bill, or a replacement part which costs a large percentage of the market value of their actual car, then they will look around for alternative (cheaper) options, usually out of financal desperation or the fact that their confidence in the reliability of any fitted replacement is no longer untenable.
During the last several years, one solution to this, was to remove the DPF altogether, often by cutting a hole in the DPF unit, knocking out the insides, rewelding the seam of the unit and refitting the now hollowed out insides. A modification to the vehicle engine management system, removed all traces of the DPF, the regeneration procedure program and essentially returned the car to that of a pre-DPF equipped vehicle. Not only did the removal of the DPF make a modern car more desirable once the threat of a future repair bill was removed, but it also made the car more responsive.
For those already experiencing DPF problems, paying a few £100 for the removal of the DPF and erradicating the whole problem altogether, was a far more attractive proposition than the quote from the dealer who wanted a four figure sum to fit a brand new DPF, which of course may also follow the same route, prove equally as unreliable and exhibit the same fault in a few years time. So DPF removal / DPF deletion rapidly became the option of choice for thousands of diesel car owners, who simply wanted the reliability and reassurance which the previous generations of diesel engines offered before we began bolting emission based modifications to them in order to please the tree hugging Eurocrats.
Unfortunately in the UK it is an offence under the Road vehicles (Construction and Use) Regulations to remove the Diesel Particulate Filter on any car, which was supplied with one fitted from the Factory, and falling foul of this law and effectively making your car illegal / unroadworthy can invalidate your motor insurance, which may leave you facing huge costs should you be involved in an accident and your insurer refuse to pay out for your own losses (and potentially also pursue you for any payment they have made to any third party). You could also face a motoring conviction and penalty points on your license as the Police may choose to prosecute you for having no insurance should your insurer revoke cover on this basis.
Because removing a DPF is effectively an illegal modification and is contrary to the Construction and Use regulations, it is also impossible to insure a vehicle which has been modified to remove the DPF, so you will also be unable to insure the vehicle even with the removed DPF listed as a declared modification.
In addition to this, from March 2014, the Diesel Particulate Filter has become part of the MOT check in the UK and any vehicle supplied with a DPF from the factory which has since been removed / modified will fail the MOT test until a time where one is refitted, at significant expense to the owner. Whilst the MOT is a visual check at the time of writing this, it will probably only be a matter of time before a similar test is adopted over here to the one which already exists in parts of Europe, namely a diagnostic check made on the vehicle to ensure that the DPF is in place and in working condition and that the vehicle hasn’t had the DPF written out of the Engine Management System, so its only a matter of time before the invisible art of knocking the insides out of a DPF, and refitting it to make it look like the original DPF is still in place becomes detectable, so probably best avoided.
Since the changes in the UK MOT laws, many owners who removed their DPF’s at an earlier time are frantically trying to sell their vehicles on the second hand market cheaply, as refitting the factory DPF is a prohibitively expensive exercise so great care should be made when buying a second hand diesel car of an age where a DPF would be a mandatory requirement, as you may unwittingly purchase a vehicle which has had its DPF removed by the previous owner and be faced with a failed MOT and a huge repair bill to put the vehicle back to its original factory specification.
The ongoing problems with Diesel Particulate Systems needs to be addressed and if systems like this are going to be forced onto car owners then they need to be fit for purpose with a manufacturers warranty which gives the owner some protection in the event of a failure, plus the confidence to buy a car with this level of technology.
In the United States there is a law, where car manufacturers are legally obliged to offer a full no quibble 80,000 mile / 8 year warranty on a huge list of emissions based equipment against failure and this has been in place since 1996. In the UK such a law would also encompass other problematic components such as faulty EGR valves, Turbos and the latest round of DPF failures, surely consumers in the UK deserve a similar level of protection to those in America?
