Diesel remap & tuning boxes will my diesel particulate filter DPF cope?


Diesel cars have come a long way in a very short time. Not that many years ago “performance” diesel cars were simply unheard of. With the introduction of smarter fuelling, injection and turbo-charging systems it’s not uncommon to see modern diesel cars knocking on 250BHP from the factory.

Not everyone can afford one of Germany’s finest 3.0 twin turbo 155MPH diesel power plants, leaving many power hungry motorists opting for diesel remapping and tuning boxes to help unlock those extra horses and torques.

Gains of up to 50% from a simple remap or tuning box are common place, so lets learn a little more about them.

Diesel Remapping


Diesel remaping is the process of changing the programming on your cars engine control unit (ECU). The ECU is the brain of a modern car and controls such things as ignition timing, air/fuel mixture and (on turbo cars) boost pressure.

On modern cars remapping is performed by plugging a flashing device / laptop into the vehicles diagnostic port (OBD2). The old “map” is saved and a replacement map is flashed / uploaded into the cars brain. The new map alters how much fuel, air and turbo pressure is fed into the engine. Increasing these variables (within safe limits} means more power without the need for any further modifications, however upgrades such as free flowing exhaust systems and larger inter-coolers can compliment a remapped car.

This process can be reversed however it is possible for dealerships to tell that the vehicle’s brain has been “played with”. This is often referred to as the TD1 flag (VAG vehicles).

This can lead to issues in the event of a warranty claim. Remapping should be declared to your insurance company.

Diesel Tuning Boxes


Diesel tuning boxes work by intercepting the signal between the ECU and the fuel injection system. The device alters this signal and allows it to inject more fuel into the cylinders thus producing more torque and power.

One of the biggest advantages of a tuning box over a remap is that these can be fitted at home without any mechanical prowess and removed very quickly. They do not alter the vehicles ECU in any way and are often promoted as “untraceable” and therefore warranty “safe”. These type of boxes essentially piggyback the existing sensors, fooling them into increasing fuel and boost pressure. These are not to be confused with the “resistor in a box” solutions from eBay.

Like remapping, a tuning box should be declared to your insurance company.

What does this mean for your diesel particulate filter DPF?

Concerns over DPF longevity are rightly voiced among those who have experienced first hand the side effect of all this “unlockable” power to be had from remaps and tuning boxes. The extra power is gained my these methods are a result of extra fuel and turbo pressure being fed into your engine. A side effect of this is that your engine will run richer, creating more far more soot and diesel particulate (PM) which will could clog the DPF at a much faster rate. This will very likely result in more DPF regens and reduced life of the filter.

What about other components?

It’s not just your diesel particulate filter that’ll take a hammering. Extra horse power and torque has an uncanny power of highlighting other components that are either worn or unable to cope with all the extra stress. Clutches, flywheels, gearboxes and differentials may require replacing or upgrading to cope with the extra grunt.

EGR & DPF removal

We’re increasingly seeing remapping services combined with EGR deletes and DPF removal. We strongly advise against this. Alerting the emissions controls in any vehicle is an offence. You’ll fail the MOT and invalidate your insurance.

More about DPF and EGR removals in the articles below

Our Advice

Our advise before you opt for a diesel remap or tuning box is to do your home work. Speak to a specialist and use a reputable company / supplier with expert knowledge on your vehicle. We would suggest trawling the owners club forums and read owners experiences.

We need your help!

Has your car been remapped or had a tuning box fitted? Have you had issues with your DPF? We want to hear from you! Please leave a comment in the box below.


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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17 comments on “Diesel remap & tuning boxes will my diesel particulate filter DPF cope?
  1. R. Marshall says:

    What is not mentioned in this article is that tuning boxes make your car unroadworthy, because it no longer meets the emissions requirements set when it was new and that’s just one of the several laws that chipping/tuning boxes contravene. The fact that the car passes an MoT Test is irrelevant. The issue is that enforcement of the law is very lax… at the moment.

  2. Dave says:

    Providing you use a decent tuning box such as DTUK above you won’t have issues.

    We have fitted loads and never had any issues.

  3. P.Holmes says:

    I havea tdi tuning fitted to my cr 1.6 tdi if used responsibly it saves fuel my emissions are extremely low as I add 2Ehn and dipetane to my diesel just by adding these halves emissions.

  4. Simon says:

    I have a mondeo 163tdci,six months after comnecting chip I have had dpf problems.Which cost £300 to clean and investigate pressure problem.

  5. Paul Anderson says:

    I had my Peugoet 406 2.2 HDi (2001 year model, 136 bhp) remapped. This was the first mainstream production car to be offered with a DPF.

    The remap did increase the performance beautifully and I experienced no DPF issues.

    However, these early DPF systems used a fuel borne chemical catalyst (Eolys – trademarked cerium based additive produced by Rhodia – formerly Rhone Poulenc) to reduce the temperature at which accumulated soot would ignite. The additive is stored in a tank at the rear of the car and is automatically administered, under ECU control, to the fuel tank whenever fuel is added. The amount added is dependent upon how much fuel is added added to the tank.

    Later DPFs do not use this additive based system and therefore I advise caution when considering remapping. It is likely that you will be asking the DPF to cope with more soot and thus passive regeneration will not be especially effective and require the car to attempt active regeneration cycles more frequently.

    Active regeneration involves additional fuel being injected into the engine during the expansion phase of combustion cycle.

    Failed active regenerations will cause the engine oil to become contaminated with diesel fuel which is not good at all. Oil level will rise, lubrication will be affected. It could lead to engine runaway. This is when the engine runs on its own oil, over-revs massively and fails catastrophically. And expensively.

    I now run a Mazda 6 2.2d Sport. 179bhp standard, which is a lot more than the 136 my Peugeot delivered in standard tune. So the cause for remapping is less already. It performs pretty well as it is. I am avoiding the temptation to remap for the reasons described above.

    You can add cerium based additives to the fuel tank to assist regeneration but the downside is that these do leave some residual ash in the DPF which cannot be burned away. Use them cautiously.

    I fed the Mazda one bottle of Wynn’s professional DPF cleaner and regenerator when I took delivery of it as a used car. As a precaution. Along with BP Ultimate Diesel the performance has firmed up slightly (it was never slow in the first instance) and I an confident that the engine is running at its best potential.

    DPFs are renowned for being high maintenance devices but you can advert much of the risk of costly repairs by following a few simple ‘policies’:

    1. Use high quality fuel.

    2. Drive it sympathetically – don’t lug it about at stupidly low RPM – aim to be above 2000 rpm is my suggestion – you won’t save fuel by being in 6th gear at 40mph with the engine barely breathing.

    3. Let is stretch its legs every week or two. Contrary to the way that petrol engines respond very well to twenty minutes of high revving usage (never do this til fully warmed up in ANY car) diesels benefit more from sustained light load. Cruising on the M’way at 70mph? Dropping to 5th gear or even 4th gear for half hour or so will do it the world of good. Use 3rd in town. You will not use any more fuel than slugging about in 4th.

  6. Angry Audi Owner says:

    We initially had EGR issues after the Audi ‘fix’. EGR was removed and at the same time remapped from 140bhp to 170bhp. We’re now experiencing the dpf problem every couple of weeks and despite what the garage told us (supposedly reputable) we’re certain that the remap is the cause as there were no issues previously. Stumbling on this forum, it looks like my next option may be to try reversing the engine remap and put it back to 140bhp so that the dpf isn’t having to cope with so many particles being pushed through… once I’ve cleared it again!

    • Karl says:

      Hi Tracy

      It might not be the fault of the remap but it certainly won’t be helping.

      The EGR valve changes weren’t the only thing the “fix” did. Changes to the injection system may well have increased soot and particulate output. Might be worth having a code reader check the DPF status after a regen as it could be nearly full of ASH – this can not be removed a DPF burn. This leaves very little room for the soot particulates and therefore making DPF regenerations much more frequent.

      Let us know how you get on.

  7. Tobs says:

    Looking for assistance as my audi Q5 diesel particulate filter was blocked and removed but now it’s smoking sometimes and it’s over a year it was removed..

    I ‘m based in Easterncape, S.A. so where can I get assistance to remap & tuning.

  8. B says:

    I had the emissions fix 6k miles ago dpf regeneration droped from 300miles to 150miles between dpf regeneration.
    Decided to get it reversed now regeneration is every 85miles much improved mpg and performance,

  9. Peter says:

    Instale un chiptunning hace dos semanas y ya he tenido problemas con el dpf, me han tenido que hacer una regeneración de una hora en el taller. Pero la verdad es que el chip es una joya, se nota muchísimo, parece otro coche. Creo que optaré por ponerle un mando a distáncia y conectarlo solo puntualmente. Esta es la única página que alerta sobre los posibles problemas del dpf instalándole el chip. Mazda 6 143c.v.


    Install a chiptunning two weeks ago and I already had problems with the dpf, I had to do a regeneration of an hour in the workshop. But the truth is that the chip is a jewel, it shows a lot, it looks like another car. I think I’ll choose to put a remote command and connect it only on time. This is the only page that alerts you about possible dpf problems by installing the chip. Mazda 6 143c.v.

  10. damian says:

    I have installed box in my 1.6hdi. After two weeks of driving fap pressure rise from 4 to 20mbar. I have decided to put the car to factory settings.

  11. m walters says:

    Had my A3 (38K miles)from 140 to 170 remap last week – already the DPF light has come on.

  12. Sam says:

    Remapping is rather dangerous. Would you really trust some blokes with a laptop and rolling road to produce a better map than the manufacturer? I’ve been tempted to get a remap in the past, but no remapping company has yet told me how they scientifically arrive at the power gains they quote. In fact several ‘reputable’ tuning companies get quite nasty if you ask about the effect of a remap on things like clutch, gearbox, turbo, dpf. I know of several companies offering remaps for VAG vehicles with power gains greater than than the turbo can handle, particularly the 1.6TDI. If remapping companies could prove that their advertised power gains are within tolerance of all components and won’t overload the dpf, I would have my car remapped, but they can’t, so I’ll leave it in its standard state.

  13. Robster220 says:

    my Mercedes 2012 c200 bluefficiency shows its factory option datacard has detuned option (M013)(engine reduced performance) to probably meet tax and insurance bands etc . now this 2143cc engine @ 136bhp surely has scope for extra/normal tuning.
    This om651 engine comes in 2 other states of tune of 170 and 204 ps albeit with twin turbo rather than my single turbo,,,,other only differences were mine has reliable solenoid injectors and the other 2 tunes had unreliable piezo injectors but think they got recalled to be replaced with solenoid type anyway..
    ahh im torn wether to leave or remap… I unfortunately had a works fiat scudo van 2.0jtd years ago at 84bhp and got a 136bhp hdi map done (same engine rebadged) what a difference. but that had no dpf to worry about… id gut the dpf for reliability reasons but new mot laws are now in place

  14. Mike says:

    Had my Diesel SQ5 re-mapped to 360 bhp about a year ago. Massive improvement on an already very good car and now achieving >45mpg. However, just had first issues with DPF blocking and intake manifold flap valve sticking. Audi say that the re-map will cause this about every 50,000 miles. The rest of the running gear/ etc has loads of tolerance by design

  15. David Hunt says:

    I have a 2012 2.0 TDI Blue Motion VW Scirocco that I had re mapped in Germany from 140 to 180.
    The guy doing it showed me that the 180 map was already in the car and he just swapped it over without installing anything new.
    The cars performance was an extra 10mph top end however the acceleration was greatly improved.
    The DPF filter light started to come on at least twice a month. It goes off within 15 minutes of driving between 2-3000 revs in a lower gear constantly. Annoyingly this effects how much fuel I use.
    Have just used Redex DPF Cleaner and Redex diesel treatment to see how it gets on.
    As I am now in the uk and not on the glorious autobahns anymore I am seriously considering having the car put back standard as 70mph top speed in this country compared with Germany fast as you like autobahn gives my car no benefits.
    I was wondering if this would help with the lifespan of the dpf or if the damage is already done.
    I have considered selling and changing to a petrol version as the dpf light is so annoying

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