Can the VW VAG EA 189 NOx emissions fix be reversed? Is a remap the answer?

All the help and advice in the world isn’t going to make the issues with the EA 189 NOx emissions fix go away. EGR valves will still fail, DPF filters will clog up and owners will still be the ones picking up the bill for VW’s lies and deceit.

What we’re being asked time and time again is can the emissions fix be reversed.

So, Can the emissions fix be reversed?

This is a tricky one. As we understand it the changes to the engine management system go above and beyond what remaps would be capable of changing. We believe that the fix makes changes only possible by “flashing” the entire ECU with new settings and features to help reduce NOx output. 

These changes include:

  • Reduction in fuelling at lower revs (reducing torque)
  • Changes to the injection pattern
  • Changes to the EGR behaviour
  • Addition of an “air straightener” into the intake (1.6L engines only)

The changes have resulted in the following for many owners

  • Reduced power
  • Increased engine noise
  • EGR valve failure
  • Injector failure
  • DPF filter blockages
  • Reduced MPG / Fuel efficiency

We understand (at present) that only VW can fully reverse the software update. At this point VW / VAG have point blank refused to entertain this idea.

Can a remap “fix” my car?

We (rightly or wrongly) have been careful not to recommend a remap to unlock the power lost to the fix due to the possibility of even more particulate matter being produced. Increased PM means more DPF regeneration cycles, less MPG and eventually DPF filter failure / blockage. 

What is a remap?

An engine remap is the process of altering or replacing the software in a car’s ECU. This changes how the engine performs, in most cases increasing the power output by up to 50%. Changes the ECU during a “performance” most commonly affect the fuelling, ignition and “boost” tables. This increased fuel and air creates a bigger bang in the engine, resulting in more power.

The remap is usually “installed” via your car’s diagnostic port (OBD2) using a laptop or a specially designed handset. 

What the internet says

We’ve put together some ideas / claims that have been flying around the internet.

  • Remapping allows you to flash different versions of the software – an example being that you can fit a different engine into a VW / VAG car and re-flash the ECU to run an entirely new engine.
  • Get the “170BHP” remap – the guy is “very legit”
  • A garage with the Odis online will be able to restore the ECU version – back to pre-update settings.
  • TerraClean will help clear and EGR / DPF blockages caused by the emissions fix
  • “Its simple to do with the correct tools… The old version of the software is free. A re-flash should cost £50-£100”

With so many people claiming remaps are the answer it’s very strange this “simple” fix… for the VW fix isn’t been advertised by every garage / tuner with the correct equipment. With so many unsubstantiated claims out there it isn’t difficult to why so many people are confused about which way to turn.

We really need your help on this one

If you can cast any light on how the software fix can be reverse please do get in touch. Are any of the claims above correct? Can your company reverse the emissions fix? Have you had your car fixed? If you’re a tuner, VW ECU boffin or have information which could be of use then please do get in touch. Leave us a comment below or email karl(at)

A work in progress

We put together this article to help cut through the static and bullsh1t that seems to be circulating around the internet. Therefore please treat this page as a “work in progress”. We’ll be updating it as often as we can, hopefully we’ll strike gold and report back with the “fix” you all quite rightly deserve.

Look before you leap!

We’ve been made aware of tuners / remapping outfits actively seeking disgruntled owners, claiming to be able to reverse the fix. We’re very concerned that owners will opt for an untested and proven solution which could cause even more damage than the  EA 189 NOx “technical measures” have already caused. Our advice is to sit tight and see is a knight in shining armour  emerges who is able to offer a proven and reliable solution.

Read more!

If you’ve found this article helpful you might also like to read our other dieselgate – VW emissions fix articles


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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 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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14 comments on “Can the VW VAG EA 189 NOx emissions fix be reversed? Is a remap the answer?
  1. Muhammed Azeem says:

    Anyone know a reputable garage that can reverse the fix on my passat cc 2011 since its always doing a dpf regen unlike before online doing it sometimes

  2. Muhammed Azeem says:

    I would like the previous firmware installed on ecu rather then a remap to make it faster and better fuel economy

    • Karl says:

      Hi Muhammed

      We’ve yet to hear from anyone who is able to provide proof that they are able to reverse the update. We’ll let you all know as soon as we do.

      Cheers Karl

      • Andrew Sinnitt says:

        Can’t the data from a “unfixed” ecu be copied and flashed onto another ecu. Or can I get an ecu from a crashdamaged/scraped car and have it programmed to my car?

  3. Daniel Oros says:

    Where on internet have you find that a software revert can be done?

  4. lamb says:

    I cannot believe that the original software for the range of engines accociated with the emmisions problem is not available from VW/Audi etc but also in each garages software “store”.

    If you are loading in a new set of software you upload and keep a copy of the original.

    If its more complicated, and you have “damaged” the hardware to load the software then change the hardware control device and load in the old software?

    May be, it will add cost to the process and reduce company profits?

  5. B says:

    After 6 months trying to get my car back to original i finaly found a tuner who could do it,
    First i tryed a remap seemed to help with performance but had it removed as regens got more frequent, then a tuner said he could make the fix software work tbe same as the original time between dpf regeneration went down to 70miles,
    Then found someone who put the original pre fix software back, everything working how it used to so pleased.
    Beware only go for an original map and check the software code before its installed it should be a lower number than the fix code.

  6. Martin Phillips says:

    I had my Tiguan fixed by VW in Dec 2016, since then nothing but problems, all well publicised, had an EGR valve replaced thought of part exchanging, but got in touch with Gary from North Wales Tuning, he found an original code for the ECU, VW wiped it clean when they fixed it, and reversed the fix, like it came out of the showroom, can’t thank him enough.

  7. Gerald Peck says:

    My wife has lodged a complaint with Audi UK and requested the original software is reinstalled on her A3 2.0TDi. We are not holding our breath! Surely this option should be made available to all who request it, as this would cut a lot of the criticism of the VW-Audi group at very little cost to them.

    From what I have read on the Internet, it is likely that my wife will get a satisfactory response Audi UK. Therefore I have already started looking for someone who can put the original software back for the sake of marital harmony.

  8. M1 Commuter says:

    A standard remap just amends the fuel and boost tables, and this is likely to make more soot compounding the DPF and EGR clogging. It will not revert the multi-stage injection changes or the more aggressive EGR profile that the VW fix introduces.

    I immediately noticed loss of low end torque after the fix, and have just paid to have my 2013 2.0 Audi TDi back-cycled to a genuine version of the pre-fix Audi Bosch ECU software. This was achieved by a tuner who had previously copied vehicle specific files from identical vehicles immediately prior to release of the technincal measure. I also had my car tested on a rolling road both with the fix applied and then on the old code with a remap:

    POWER – Stock 177hp, Post Fix 185hp @ 4419 rpm, Remap on old software 224hp @ 4000 rpm
    TORQUE – Stock 380Nm, Post Fix 411Nm @ 2200 rpm, Remap on old software 457Nm @ 2,400 rpm.

    The tuner told me that most remaps just write new tables to the boost and fuel parameters using the canbus plug. But to undo the damage introduced by the fix, you need to write a full ECU file (if you have one). Some can be written via the plug connector, others entail ECU removal. Obtaining an original copy of the pre-fix software in the first place however requires ECU removal.

    Contrary to what Honest John reports, rather than introducing a triple stage injection, the fix actually removes or reduces the pilot stage so reverting your ECU to the original version of software actually re-instates it. Having the pilot injection makes the engine smoother and quieter, and hence widespread reports of increased noise after the fix correlate to this. I suspect the modified tiguan profile VW are now issuing has applied further adjustments.

    So VW / Audi were technically correct that my power and torque would not be impaired, but they lied about the economy and the future life and reliability of the car. In fact on my vehicle the map I got with the fix comfortably exceeded the original torque and power specs. However, economy was about 10% down and I noticed that DPF regens were occurring much more often. This would have affected component life and I am happy that the tuner I have used has successfully cancelled this death sentence and has given my Audi a new lease of life, with power torque and economy all better than ever.

  9. Andy Burns says:

    Audi A1 16D…loss of power..DPF light on 2 maybe 3 times a week…
    Fuel eco down ….
    Not good not good at all
    Anyone no where I can get the ecu flashed back to original…audi liverpool waste of space ..promise the world deliver nothing worst dealer experience ever !!!@!!

  10. paul dickson says:

    i have asked many times for the fix to be reversed but audi says no , as i did not ask for it when it was in for a major service but applied anyway . i feel i have been duped by them , and have now also been left with my 2012 audi a3 2.0 on my drive in limp mode having DPF ,EML , and glow plug light flashing, and have had to borrow a car for work , and now they want to do a diagnostics check to see whats wrong as if they dont know , should i let them have it back or live in hope they may reverse this so called fix that ruined my car ,

    • Long time VW owner says:

      I would be tempted to print off as much material as you can find that either support or prove that the ‘fix’ is linked to problems and challenge them on why they cannot restore your previous map. I am hopeful that within 12 months they will be forced to act – it only takes 1 customer to be successful in having VAG restore a map and they’ll have to make it available to everyone sooner or later.

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