Will my car fail its MOT if I have the DPF (Diesel Particulate Filter) removed or gutted

DPF removal gutting MOT test fail pass diesel particulate filter

Surprisingly, DPF related googling now accounts for the vast majority of the traffic to Hypermiler. Therefore we are always looking to expand our library of DPF information for all our knowledge thirsty visitors.

One of the hottest topics of late is the effect removing or gutting your DPF (Diesel Particulate Filter) will have on your vehicle’s ability to pass its MOT test.

I am very lucky to have a close friend who is an MOT inspector, he was able to fill us in on some rather surprising information. We’re not going to name our source, but he was happy to answer the following questions.

Will my car fail its MOT if I remove my DFP Diesel Particulate Filter?

Yes. From Feburary 2014 MOT testers are required to check for a the presence of a DPF filter. If it’s gone, so are your chances of an MOT pass. Here’s the official line from the Gov.uk website (here)

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.

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

The above is not to say your local MOT tester might turn a blind eye or notice that your DPF has vanished, but if he’s doing his job correctly your car will fail.

Will my car fail it’s MOT if I have the DFP Diesel Particulate Filter gutted?

Now this is the interesting part, what happens if your DFP Diesel Particulate filter gutted?

This process involves cutting open the filter, removing the internal filter matter and welding it back up. Without the filter in place there is very little to capture your diesel particulate matter and even less to get clogged. But will it pass it’s MOT?

Our man, begrudgingly says YES! Even with signs that the device has been “tampered” with, they can not fail the vehicle as long as it meets emission regulations. In his words, they “must give you the benefit of the doubt, the most you can get is an advisory”.

Before you go reaching for the angle grinder and welding mask were sorry to say that its not quite that simple. If you do take the drastic step of removing the intermal “gubbins” from the filter you will need to have the ECU modified to remove the DPF sensor warning system. This often called remapping and will disable the DPF part of your vehicles ECU (brain) and in most cases provide you with a nice increase in performance. This has to be done by a specialist – google is your friend.

UPDATE!

We’ve been recently made aware that the government and VOSA are very aware of the legal and environmental issues surrounding DPF removal. At present the MOT test CAN NOT detect that your DPF has been gutted / removed or tampered with but…. changes are afoot.

We have been reliably informed that the MOT test will soon be changing to include a test for diesel particulates and soot. This test measure the effectiveness of your DPF and your vehicle will fail it’s MOT if you’ve been naughty.

It’s still very early days but please be careful when considering the removal of your DPF filter.

 

A word of warning

Like you, I’ve been bitten by DPF issues, my Nissan Qashqai DPF had to be dealer regenerated a number of times, costing in excess of £900 alone. DPF filters are there for a reason, they are designed to improve your dirty oil burners emissions and help improve air quality. We certainly don’t condone the removal of your DPF filter but we fully understand your frustration with the bloody things!

For more information on DPFs you might also like to check out the following pages

If you’re having DPF related issues please leave a comment below and we (or another visitor) might just be able to steer you in the right path.

Related posts:

About

Karl is the editor and owner of this glorious website. He currently writes for numerous environmental websites, producing content for the greater good.

His experience in graphic design, Wordpress and all things automotive have helped sculpt Hypermiler.co.uk into its current form from very humble beginnings.

He has numerous IT qualifications, a red belt in Taekwondo and likes craft Ales.

Get in touch via our Contact Page

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18 comments on “Will my car fail its MOT if I have the DPF (Diesel Particulate Filter) removed or gutted
  1. Kevin says:

    Regarding dpf cleaners before I started to use stp dpf cleaner in my insignia the light would come on and it took around 20 to 25min high rev driving to get it off, since using additives it goes off within five mins driving on dual carriageway a distinct improvement,also the frequency of dpf light coming on has gone from roughly every week to roughly seven to eight weeks,so I would recommend using the stp additive.

  2. Peter says:

    Where, near Leeds, can I get the DPF on my BMW 530d gutted and the car remapped?

  3. Marc says:

    Firstly, using chemicals to clean your DPF can in most cases be a short term fix. If your light goes out then fine;however, if it rears its head again then you more than likely have a build of ASH. ASH is none combustible so using chemicals will not help. You either need to replace or have it professionally cleaned. Chemicals only lower the emissions temperature to help burn off the soot. DPFs can block prematurely through no fault of their own, it is always good practice to have the emissions system checked with any DPF problem.

    DPF removal is illegal and the next round of MOT upgrades will include a test to make sure the DPF is operational, if it is not there then it is not operational. This happened with CATS it is only a matter of time before this happens and with the VW Diesel Gate scandal this will only speed things up, so dont remove have the problem fixed correctly.A car in normall circumstances whould only require ONE clean in its lifetime.

  4. Chris says:

    I gutted my DPF after issues and had the car re-mapped to avoid any problems with the ECU. Now my economy is roughly 20% improved so yes I emit more soot particles because of no DPF but I use a lot less fuel so this must reduce the carbon and all other emissions as the car is running more efficiently. These are just a sop to the EU – the carbon is still produced and burnt just only when you are on a motorway so it moves the problem from towns and cities to the Country.

  5. Ulpian says:

    If you are found to have removed the DPF you will be liable, and so will the workshop that removed it, if they are caught. MOT test centres passing such illegal cars will be fined and struck off. A used car buyer needs to check the MOT test centres to make sure they are reputable. Caveat emptor.

  6. mariush says:

    could be vw group emission problem reason for blocked DPF ?

  7. Grimreaper says:

    The whole crux of the matter is being completely ignored, the talk of removing a DPF is down to the fact that motorists are sick of paying the price for ill thought out ideas and poor R&D. If the DPF was reliable and lasted for the lifetime mentioned in the service book (usually around 120k miles) then the majority of motorists wouldn’t even know that a DPF system was fitted, let alone be looking at spending good money to have it removed. Reading some comments around the internet about the whole DPF removal thing, you would think that some people are taking the fact personally that others are resorting to removing their DPF systems, as if it is just being done to spite them!.

    Nobody wakes up in the morning, and thinks “Hey lets remove my DPF today, because I haven’t anything better to spend £400 on” it’s usually done out of sheer desperation because they are sick of the car constantly going into limp home mode, or needing expensive cleaning, or forever visiting the dealer and spending £100’s getting it regenerated or perhaps they just don’t want to spend up to £2000 on replacing a component on a car which hasn’t covered much mileage or is only just out of warranty. That situation wouldn’t be acceptable on a cambelt or a gearbox or an engine, and it shouldn’t be acceptable on a DPF.

    In the US, there is the Federal Emissions Warranty, which since 1996 has covered the American Consumer from failures of major emissions components on their vehicles for a period of 80k miles / 8 years and is backed by Law. Why doesn’t the same protection exist for UK consumers?, if the vehicle manufacturers aren’t confident enough to offer a similar warranty on DPF systems, then they shouldn’t be being fitted to cars!.

    What is also often missed, is that as a Diesel Engine ages, then its injectors also age and become clogged, as do EGR Valves and Swirl Flaps and most other emissions control components, in short the older the engine and its components, the more smoke and soot it will produce, and whilst some are smug that they haven’t had any DPF issues on their relatively new cars, lets see if that is the same after 60k, or 90k Miles, when no doubt the higher soot output will mean more frequent regenerations, more stress on the DPF and ultimately a higher chance of that £2000 replacement bill.

    In the 1990’s Diesel engines used to cover 400k – 500k miles routinely, often still with the majority of their original factory components intact, if Diesel cars are starting to rack up huge bills with less than 100k on the clock, then something is badly wrong and the UK consumer need to be demanding answers from the Car Manufacturers as to why this is happening and insisting that better warranties are put in place to protect them, because its not like the cars are getting cheaper to make up for the commensurate drop in reliability is it?. But wait!, this is the UK, home to the spineless consumer with no backbone and no solidarity. So you get what you settle for.

    • Mark McCallum says:

      Totally agree with that comment! I’ve been having problems with my 2010 Subaru Outback Diesel since I bought it privately last year – I cover about 25k miles a year and mostly drive on motorways. I’ve had the dealer do a DPF regeneration, I’ve had it cleaned professionally (it lasted 3 months and approx 7k miles, only to be told its 92% blocked again), an engine oil and filter change due to ‘oil dilution’ (where fuel is mixed with the engine oil to increase temperatures to attempt to burn-off more of the soot in the DPF and thus risking more engine wear). The system is a total engineering failure and should be rectified by the manufacturer of the car or got rid of completely as a technology. Its attempting to make a fuel that is inherently dirty, cleaner by using a quick fix that is useless. My next option is to replace the DPF (£1250 plus labour) or get it gutted (£450 all in) and risk future MOT failures, if the updates to MOT emissions testing are brought in. I don’t want to drive illegally or pollute more than I am already but the latter option is the more tempting at the moment! All in all, its bloody frustrating and surely is a massive future issue for the whole country…..

  8. Paul says:

    How can we burn dpf on UK motorway if we drive 70mph and it’s mostly not constant speed and exhaust gasses temp is to low to burn this thing? We need keep temp between 300-400*C and with this speed even on lower gear is impossible! I have diagnostic tool and I know how high the temp is. Diesel in not for eco driving anymore! We have to drive 100mph and floor the car to burn it!

  9. JIMMY/J says:

    MY NEW HONDA 2015 CRV HAS JUST HAD A REPAIR TO THE DPF SYSTEM,THE FULL WARNING LIGHT CAME ON WITHOUT ANY PRIOR WARNING AND IT ADVISED ME TO TAKE THE CAR TO THE HONDA DEALER ASAP.THE DEALER SAID HONDA U.K.ADVISED THEM TO CHANGE THE ENGINE OIL AND FILTER BECAUSE IT HAD BEEN DILUTED ALSO TO DO A ECU SYSTEM UPDATE,THE CAR HAS ONLY DONE 14,000 MILES.I WASN;T ASSURED THIS WOULD NOT HAPPEN IN THE NEAR FUTURE,SO I AM SERIOUSLY THINKING OF GOING BACK TO A PETROL CAR.

  10. Nigel says:

    The simple answer is don’t buy new cars run old ones the dpf system became mandatory across the EU in 2005 buy and older diesel made before then and the chances are it won’t have it. M 1998 Citroen xantia turbo diesel had a cat fitted when I bought it I removed it the bhp went up from 90 to 95. It goes faster and burns less fuel it has passed every Mot since. Catalytic converters on diesels is a huge con constructed by the government agsns the consumer diesels are currently only tested for smoke production particulates in the exhaust are not currently measured. Now they put catalytic converter on the reg documents and have made it illegal to remove them. A pointless useless device in a diesel vehicle. Dpf is a scourge in the pockets of the consumer and is just another way for the government to try to reach the EU emmisions targets. I don’t suppose lorry drivers have these problems doing stop start deliveries all day so why don’t the public have access to the same technology? God forbid if a dpf blocked upnon a fuel delivery tanker to the ambulance or police filling tanks at their depots and put the tanker truck in limp home mode. Yes the biggest diesel guzzeling trucks pushing out the most pollution never have this problem at all. Kind of makes you feel a bit stupid as to why you don’t question this.foes a diesel train suddenly launch into limp home mode no never becsuse it dissent use dpf technology. Cruise ships are still burning basically crude oil and they don’t have dpf issues do they.yet all these big diesel munching engines are permitted to stink up our our atmosphere every day whilst drivers psy for it with silly ideas like the dpf.

  11. My skoda octavia diesel sdi covered 500,000 mls, No problems, No dpf, No dmf, Where’s the problem let’s get back to old proper Diesels!

  12. SanBrag says:

    We live in Guildford and have a Suzuki Grand Vitara (92 000 miles)and in June last year we started with DPF issues. We had it looked at at a Suzuki authorised service station and they temporarily fixed the pipe.
    Now, we started hearing a terrible noise coming from the engine and major loss of power. When we got it fixed last year, we were told that they would give us a call back when the part came in to get the filter substituted. Never got the call. Now we’re in serious trouble as closest Suzuki service station can only take a look at the car in 2 weeks time so we’ve had to rent a car to get by for the next 2-3 weeks. Should we inquire into “gutting” the dpf? We’re getting quite fed up of wasting so much money on the car.

    • Karl says:

      Be careful. Tampering with the emissions systems of a vehicle is illegal and you will invalidate your insurance.

      Changes are also afoot to detect if a DPF had been gutted in the MOT test.

      I suggest seeking advise from an independent Suzuki specialist of even try and owners club forum before you take drastic measures.

      Good luck and let us know how you get on.

  13. Laura says:

    Hi,I have a 2008 2.2d x-type Jag that’s only coveted 60,000. I bought it about three months ago but last week the dreaded DPF Full amber warning light came on. After the garage ran diagnostics,they found the DPF to be empty but decided to remove and clean anyway. All was well until aboit 50 miles later when a red DPF light, engine light and flashing coil light came on! Anyone else had this issue and if so, what was the problem/fix?Any help at this stage would be much appreciated as I don’t want to keep throwing money at it with no fix. Thanks, Laura

  14. B Dewhurst says:

    I had my filter removed and remapped can I just put a new filter on

3 Pings/Trackbacks for "Will my car fail its MOT if I have the DPF (Diesel Particulate Filter) removed or gutted"
  1. […] With this is mind PLEASE seek advice before you confider removing your DPF but you might also want to read our article about MOT rules on DPFs […]

  2. […] Will my car fail its MOT if I have the DPF (Diesel Particulate Filter) removed or gutted […]

  3. […] properly VOSA have been working on this for a few years now here is a copy n past from this link Will my car fail its MOT if I have the DPF (Diesel Particulate Filter) removed or gutted | Hypermili… We’ve been recently made aware that the government and VOSA are very aware of the legal and […]

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