Octavia speedometer adjustment VCDS

[anonywsx]

Hi, I've got an Octavia 3 G-Tec (2020), which has a pretty bad speedometer calibration. The tires are 205/55R16, and when driving 100 km/h (speedometer) the real speed is somewhere around 94 km/h. That wouldn't bother me otherwise, but it seems that it affects the mileage display too. I drive with my car a lot on workdays and have a GPS tracker so my employer pays me for the mileage I've had to use my car for work. I also keep a  backup of my mileage on paper and I've written the start and end mileage on it. Last month the difference was about 10% (GPS says 452 km and my notes say 497 km). Usually I wouldn't mind if it was off a bit, but that is too much.

Can we adjust the speedometer error with VCDS? If, how? Wouldn't want to buy new rims for that. Thanks in advance!

[Esseesse200]

5 hours ago, anonywsx said:

Hi, I've got an Octavia 3 G-Tec (2020), which has a pretty bad speedometer calibration. The tires are 205/55R16, and when driving 100 km/h (speedometer) the real speed is somewhere around 94 km/h. That wouldn't bother me otherwise, but it seems that it affects the mileage display too. I drive with my car a lot on workdays and have a GPS tracker so my employer pays me for the mileage I've had to use my car for work. I also keep a  backup of my mileage on paper and I've written the start and end mileage on it. Last month the difference was about 10% (GPS says 452 km and my notes say 497 km). Usually I wouldn't mind if it was off a bit, but that is too much.

Can we adjust the speedometer error with VCDS? If, how? Wouldn't want to buy new rims for that. Thanks in advance!

There is a setting or something in vcds that asks for tyre circumference.. that would be the one to check and change to suit current tyres 

[Ecomatt]

All speedometers under read to allow differences in tyre circumferences. Mine under reads by 2 to 3mph from my sat nav gps speed.

I personally would take it back to a Skoda garage as your car is still in warranty and let them recalibrate the speedo on ODIS. If you mess around with it and things go wrong you will not be covered.

[langers2k]

It'll depend on the cluster but at least some will let you change the tyre circumference: https://www.golfmk7.com/forums/index.php?threads/speedometer-calibration-with-obdeleven.349584/

[anonywsx]

I've contacted the service, as it indeed still has 2 few months left of warranty (registered 6/2020). Let's see, what they'll say, I don't have high hopes though.

[Warrior193]

On 01/04/2022 at 18:34, Ecomatt said:

All speedometers under read to allow differences in tyre circumferences. Mine under reads by 2 to 3mph from my sat nav gps speed.

I personally would take it back to a Skoda garage as your car is still in warranty and let them recalibrate the speedo on ODIS. If you mess around with it and things go wrong you will not be covered.

If I recall correctly, maximum allowable speedo error, at manufacture, is 5 or 6% overread  (0% error underread)  Note to OP, have you checked speedo calibration over measured mile (if these still exist)? - or tried multiple runs in different directions with GPS?

[anonywsx]

9 minutes ago, Warrior193 said:

If I recall correctly, maximum allowable speedo error, at manufacture, is 5 or 6% overread  (0% error underread)  Note to OP, have you checked speedo calibration over measured mile (if these still exist)? - or tried multiple runs in different directions with GPS?

The error of the GPS is possible, if not likely. More so, I'm getting paid by the mile for using my car, therefore for possible GPS errors I need an accurate trip meter to see, if the GPS had any mistakes or errors. I've actually measured the distance with map tools and my previous car was great on accurate distance reading (19" wheels though). A known distance of 64,5 kilometers was around 66,5 kilometers yesterday with the 16" wheeler, so the distance error seems to be at least 3,2% or so. In time it will accumulate quite much and as mentioned, I'm used to having an accurate trip meter.

[PetrolDave]

The legal requirement for a speedo is that it must not underread and can overread by up to 10%. Practically this means that manufacturers setup their speedos to overread by around 5%, to allow for variations in tyre sizes and reduction in diameter as tyres wear.

 

This overread translates to an overread in distance also.

 

[Gerrycan]

On 04/04/2022 at 23:53, PetrolDave said:

The legal requirement for a speedo is that it must not underread and can overread by up to 10%. Practically this means that manufacturers setup their speedos to overread by around 5%, to allow for variations in tyre sizes and reduction in diameter as tyres wear.

 

This overread translates to an overread in distance also.

 

I agree with you on the max 10% legal requirement and usual (about) 5% speedo overread but as tyres wear then the wheels rotate more for a given distance so the speedo inaccuracy is even worse so why would they build in an initial 5% variation for that?

 

Most of the vehicles I have owned from new over the last thirty years had pretty accurate odometers (1 to 2%) including a mk2 1.9pd and current mk3 1.4tsi but the speedometer accuracy was not good on either at 10% on the mk2 and 5% on the mk3.

As an aside the consumption display was a consistent 0.2L/100 optimistic on the mk2 and when new the mk3 was about 0.1L/100 pessimistic but after 7 years the latter is now

0.2L/100 optimistic.

 

I'm sorry but I have not experienced a consistent link between inaccuracy of speedo and odometer or any consequent relationship to consumption accuracy either.

Edited 6 April, 2022 by Gerrycan