Speedometer Recalibration via VCDS - Adelaide

[Usernameless]

Does anyone in Adelaide have VCDS and is willing to do adjustments to the instrument cluster (VW - year of manufacture 2001.) to bring it's accuracy to normal values. Currently, it's 18% percent off.

It should be pretty straight-forward procedure - just manipulation of the 'distance impulse number' that corresponds to the wheel circumference value - basically, when you change wheel size, the speedo will be off, so by changing 'distance impulse number' to match the wheel size, the accuracy of speedo can be recovered.

My understanding of procedure is as follows:
- Within main directory of VCDS Selection Control Module - select '17-Instruments'

• Under instruments sub-directory there will be shown controller information (VAG number and software coding) - select 'Coding - 07'

When select code field, the drop menu will show something like this:

00??x0x: Options
+01 = Brake Pad Warning
+02 = Seatbelt Warning
+04 = Washer Fluid Warning
+16 = Sedan (only VW Jetta)
00xx?0x: Country
1 = Europe (EU)
2 = USA (US)
3 = Canada (CDN)
4 = Great Britain (GB)
5 = Japan (JP)
6 = Saudi Arabia (SA)
7 = Australia (AUS)
00xxx0?: Distance Impulse Number
1 = 22188
2 = 22076
3 = 21960
4 = 21848
5 = 22304
6 = 22420
7 = 22532

• As shown above, the last digit of the code is 'distance impulse number' (factory set = digit between 1 and 7) to be changed to any other digit between 1 and 7; in my case, where speedo reading is less than actual speed, the selection should be the number that is less than factory set number... will probably need to play with few digits to see if speed reading matches actual speed.

If above is correct, the minimum time engagement would be required - a few minutes to adjust the value and additional few minutes to test the speedo reading against GPS (low speed testing is sufficient as 18% error is read across all speed values).

Please note I am willing to pay for your engagement.

Please let me know if any concerns with above procedure description. Thanks!

[DV52]

Usernameless: Hi.

I can't help with the bit about providing VCDS (it's a long drive from Melbourne) - but the video below may be useful in calming your concerns about the actual tweak process.

Don

[Usernameless]

Thanks @DV52.

Video basically illustrates procedure that I've described above.
My biggest concern is that VCDS won't recognise 'VAG Number' automatically, so I would need to enter it manually (I have trouble finding exact number of my instrument cluster), but according to the embedded video, 'VAG Number' is identified by VCDS automatically...

The other concern I have is that if I manage, somehow, to find local car service with VCDS that is willing to deal with this (which I can't find at the moment), that they will charge me multiple hours of work for this (with pricing up to $190/hr), and it's pretty obvious that this task takes a couple of minutes only...

Just want to connect it to VCDS to check if it can be done as described above... if any complications that prevent this procedure to be straight-forward (as shown by video) arise, I am ready to give up and leave it as it is... I don't want to waste anyone's time.

[DV52]

Usernameless: hmm....... ain't nothing particularly difficult about this tweak - but this is the "normal" process when using VCDS:

1. IOEF (Ignition -ON, Engine-OFF) - connect VCDS dongle to VCDS software (this shouldn't be a problem for the VCDS user because it's the same for every car
2. Got to the Main Screen - click-on "Select" on Select Control Module
   
3. Click-on 17- Instruments
   
4. The screenshot below is for the Engine module - but it's the same for EVERY module in the car. The ONLY variable across the various different modules is the information in green in the dialogue boxes on the upper part of the picture below
   
   

In essence, VCDS works like this:

• by selecting 17-Instruments (above), the software sends a request to the car to open-up the module that lives @ address 17 (which controls the Dashboard equipment). VCDS software also asks the module to return back basic information about itself. VCDS then uses this returned data to populate the dialogue boxes on the upper part of the screen above
• I suspect that the screen layout is designed to convey a message to the user that ALL of the selectable option-boxes on the lower part of the screen only applies to the module with the information shown in the dialogue boxes on the upper part of the screen

So bottom line = the fields in the screenshot above like VAG Number, Component, Soft Coding and Extra are ALL automatically self-populated for the selected module - in this case 17-Instruments

Hope this helps - or at the very least, it doesn't confuse!
Don

PS: Maybe a tiny, itsy-bitsy issue of concern about this tweak that I know applies to more modern VAG vehicles - but I don't know if it applies to older vehicles like your MY01 build vehicle which uses older style non-UDS/ODX protocol modules

On modern cars like those built with MQB platforms, VAG have "restricted" the mechanism for changing tire-size because of the impact on the odometer reading (at least I think this is the reason). Whilst there is nothing official in the public domain - it stands to reason that artificially decreasing the tire diameter will have a consequential effect over time akin to winding-back the odometer reading of true kilometers driven

Anyhow, at least on more modern cars, VAG has dealt with this issue by allowing a coding change in tire size in ONE direction ONLY. This means that once a coding change is made - a further change back-in the reverse direction can NOT occur.

Again, I'm not sure if this happens on MY01 modules (maybe not?)! I guess if you are able to decrease tire diameter at all on this car, maybe there are no restrictions in coding-change direction???

[Usernameless]

Cheers Don.

Your explanation is very clear and helpful.
Thanks for that, I appreciate it.

I've just realised that I opened the topic within wrong forum section as there is one for coding that would be more appropriate.... Well, it is what it is - hope that help will come in some way...

P.S. just seen your edit - yeah, that's fair concern; any adjustment can cause odometer changing its value.
We'll see...hopefully I will get the chance to try. Current settings should be stored prior any adjustments to not cause further issues. Thanks for your valuable input.