Volkswagen Speedometer Error Correction


The majority of cars have a speed that has an indicated speed that is greater then the actual vehicle speed to comply with UNECE 39/00 (Rev 1) which is adopted by many countries including Australia with ADR 18/03. Volkswagen vehicles from around 2005 onwards can have this indicated speed adjusted to more accurately reflect the true speed by adjusting the deliberate error that is introduced in the instrument cluster.

Testing showed that my MY08 Golf GTI was over-reading by around 10%, the following table shows the GPS speed (handheld), the CANBUS speed which is what the odometer uses, the Indicated speed prior to the coding change and the corrected speed after the change.

The distance impluse number on my vehicle was set at 3, I changed this to the maximum value of 7 which was spot on what was required. You will require a VCDS./VAGCOM cable to make this change, the dealer could make the change but I understand that they will not do this.

Adjusting the distance impulse number does not alter the odometer, the distance impulse number is an error that is introduced for the speedometer needle.

Speedometer readings before and after correction


GPS Speed CANBUS Speed Indicated Speed Corrected Speed
40 40 44 42
50 50 55 52
60 60 66 62
70 70 77 72
80 80 88 82
90 90 99 92
100 100 110 102

There are a number of ways to display the CANBUS speed, the easiest method is to use the full sized MFD and go to the speed alert screen, press ok until three dashes show and clock ok, the warning speed is your current CANBUS speed. This is a static display so use cruise control on a flat level surface.

The other way is to use the climate control system to display the speed. See the post on this site under reference for more information on this.

Volkswagen have some TSB’s out for this “problem”.


2005 – 2006 A5 Jetta and A5 GTI, Speedometer Display

If you receive a customer complaint that the speedometer displays a vehicle speed that is slightly faster than the actual speed, this is normal. The speedometer is operating per manufacturer specifications. Volkswagen does not manufacture vehicles where speedometers read slower than actual speed. To allow for possible differences in overall tire diameter with different tire manufacturers and wheel sizes, a factor is designed into the speedometer function that increases the displayed speed. This factor does not affect odometer readings, which show actual distance traveled. Do NOT replace ANY parts for this condition.”


UNECE 39/00 Revision 1

ADR 18/03

20 thoughts on “Volkswagen Speedometer Error Correction”

  1. I have done this code change and after reading speedo against the climate control there is still a 4 – 5 km difference which is less than the 8 – 9 km it was. can it be altered more or should it be left as is? i have the VW five spoke 18′ rims.

  2. Great Advice – I have waited about 2 years for the solution to this deliberate error. Dealer eventually gave me a copy of the above TSB or similar. Wasn’t impressed.

    On my Golf Mk5 I recon I get 5% + 2km/hr error – which is exactly half of the error allowance in ADR 18/03. I ran it on the highway on cruise control for about an hour at 118km/hr (no traffic at all) – the computer said average speed was 110km/hr (the speed limit). So the computer knows the true speed – so did the Police as I went through 2 radar traps (and countless more since then).

    The tire wear argument doesn’t hold water – that makes it slower as your wheels get smaller – and it isn’t significant either.

    This much error is just plain annoying – especially since some bright spark in Germany thought it was a good idea to write the Euro standard giving manufactures 10% + 4km/hr error. (very generous). Writen for the manufactures really.

  3. Ive left well alone The indicated speed keeps me safely within speed limits on the odd occasion I see 64/5mph on the speedometer I will only be doing 60mph. I have gone past two camera vans doing just over 60 and nothing has happened

  4. My Nissan Murano 2009 while reading 118 on the dial is also telling me via the trip that my average is 110.4. My wife’s Mazda 3 reads 100 when actually doing 89Kph. However the Toyota Kluger I owned prior to the Nissan was 100% accurate. So I rang a Toyota engineer in Melbourne and he said this : “Toyota Japan do not accept built-in inaccuracy as they strive for perfection and therefore refuse to compromise for what are untimately non engineering but socio-political reasons

  5. DO NOT DO THIS MODIFICATION. It has all sorts of ramifications that remain unseen in the background. Number one: Fuel economy goes through the floor. Average of 35mpg dropped to 30. Don’t know why this should happen. Number two: Cruise control stops functioning properly. Yes the speedo error disappears completely, but the cruise which functioned in every gear only worked in sixth and not in all gears as before. I think this changes the way the engine behaves and not just the speedo function!

    1. It changes nothing to do with fuel economy, you car is still getting the same economy as before or are you saying that you have to fill the car up more often?
      Cruise control has nothing to do with this change either.
      Your “findings” are not based on any facts, sorry but changing the speedo error will not cause any of the problems you have mentioned.

  6. My 2008 Mk5 GTi speedo is well out. GPS was showing 118 speedo was showing 140, at GPS 60 kilometres per hour the speedo was showing 70.

    Will post the workshops response after I take it in.

    Bit embarrassing doing 120 (speedo) and getting passed by a bus 🙂

  7. This is FALSE!
    Don’t do it.

    My original setting also was on “3” and the speedo was way off. I set it to “7” and drove from home to work on early Saturday morning. The distance measured was 9.5 km. At work I changed it to “4” (the “highest” error) and drove back home THE SAME ROAD. The distance measured was 10.3 km!!!

    1. So setting it at 7 which would have given you a more correct speedo actually gave you no difference in km’s travelled whereas setting it at 4 did? You will not that I suggested 7 in the guide and as usual the onus is on the person making the change to make sure it behaves as expected.

  8. I talked to my friend at VW dealership. He says that Speedometer readings can really be tweaked by selecting another Distance impulse number. For all VW Golfs they came with “3” from the factory. Setting that to “7” would cause 2’000 km difference per 100’000 km on the odo. VW considers this insignificant mileage.

  9. I have a new 2011 Jetta TDI. my speedo reads 120 when I am actually traveling 110. This is annoying and I’ve never experienced this with any car before and I’ve owned dozens. I called VW and they simply stated that it is an acceptable variance and nothing will be done about it. My real concern however is on the Odometer reading. Does this mean I’ve traveled only 100,000 kms even though my odometer reads 110,000? If my car was leased and there was mileage penalty, which is usually 12 cents per km, this means I’d have to pay $1200 penalty. My car is not leased but I do get concerned about things like fuel efficiency claims that the car maker states versus reality as well as depreciation of the vehicle. Does anyone know if the odometer reading is affected by this inacuracy of the speedo?

    1. If you bothered to read the article you would see that the odometer speed is spot on. This is also indicated in the table. The only alteration that is made is to the speedo which is in line with requirements in most countries.

  10. I have the opposite prob. In my TTS the speed indicated was always 5-7 K’s over true speed. I then put on AUDI RS4 19’s to replace the TTS 18’s. With correct 255/35/19 tyres. The rolling circumference is larger as I placed both tyres next to each other. Now my speedo is bang on correct to the last K at 20-40-60-80-100-110-120.

    What I want to do is put it back so I get the 4-5 error again….as a buffer. Is this possible if my impulse (not checked yet) is at a factory 3 still?

  11. 2013 jetta TDI, same thing, off by 10% on the speedometer and off by 2.5% on the odometer. I am really ticked off. I would expect that vw would learn by now. 10% varience is not acceptable. (SAE) Society of Automotive Engineers International recommends all car manufacturers to have fast reading speedometers, but like I have quoted its only a recommendation and not a law and its not mandatory. VW chose to do this because its a generic program to fit all of its cars for a cost saving factor. So much for that special DAS AUTO that was built for you. I beleive the language that is written by (SAE) is this,” there is a 4% varience on speeds of 90 kms. per hr based on the highest number in kms. on your speedometer needle dial. Do the math, this is obsurd. And guess what these people that write up these recommendations are volunteers. Go Figure.

  12. I have the same issue here new 2015 Volkswagon Amarok… speedometer error of 10%+ relative to a Toyota Camry speedometer which no doubt also has a fudge factor. Volkswagon dont want to know about it and are ignoring our requests for remedy. Customer Care??? Oxymoron!

    1. Volkswagen is cheating and let me tell you why: VW wants drivers to drive their cars 10% less of speed limit because it benefits their bottom line by not having warranty claims during the warranty period because there is less strain on power train components. This is 2015 and not the stone age. There is no other valid reason why they are doing this. It is high time a class action suit should be pursed.

  13. I wish I saw this site before I purchased an Amarok Canyon, the inaccuracy drives me crazy, maybe they can introduce a 10 min clock advance to keep me from running late! VW think I have nothing better to do than take 10% longer to get from A to B. I will never purchase a vehicle without doing a GPS speedometer comparison. I will never recommend VW to a friend. PS my Hilux was spot on.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.