Speed Signal Problem Ibiza 6K AFN - K-Power

Hello,

I'm having a problem with the logs for K-Power. Specifically, my speed signal is 'acting up' .

I have tried various measurement devices using VAG-COM Ver.409.1 (Shareware + DIY adapter ), and all values can be easily read and logged. However, the crucial km/h values randomly jump to the actual speed , resulting in no correct measurement values , and K-Power is not possible.

The speedometer is working perfectly; there are no erratic readings or anything like that.
The error log shows an 'implausible speed signal' . The error was cleared, and a new measurement was performed. The result is that when accelerating, the km/h display works correctly. However, when disengaging at maximum RPM, it shows 0 km/h, and then various km/h readings . This measurement is useless .
After that, the car was parked (ignition off and on), and the error memory was read again . Empty, no entries .

I've done some digging through the search results and have come to the following conclusion (please correct me if anything is wrong ).

There is a sensor that provides a speed signal, outputting two signals. One signal goes to the control unit (KI), and the other goes to the engine control unit (ECU).
The signal for the AI seems to be working correctly, as the speedometer is functioning properly.
with the other signal, something isn't right (possibly a loose connection , as it works when accelerating).
My question is, where is the installation location of this sensor (is it called a G22 speed sensor? Apparently, it seems to be called that according to my search )?
Are these both the same signals, or do the Mstg and the KI operate with different signals?
From that, I could draw conclusions about whether the sensor is defective or if there's a problem with the 'signal line' leading to the MSTG (Multi-Sensor Test Gauge).
Can I measure anything there? The signal is probably only measurable while the vehicle is in motion .

I've encountered the 'implausible vehicle speed' error multiple times, and after clearing it, I haven't noticed any negative effects while driving. There's been no hesitation, no loss of power.

Thank you in advance.
Sure, here is the translation of the text from German to English:

'MFG' is an abbreviation for 'mit freundlichen Grüßen,' which means 'best regards' or 'sincerely.' It is commonly used in German-language emails and letters.

Hi,

The speed limiter should be located on the differential.
I can only speculate as to how those specific control units came to be, so I won't comment on that.

Best regards, Rainer.

Okay, then I'll take a look when it's a bit warmer (-8°) .
@Rainer
if you're already there, a quick question about K-Power .
Do I need to start the log exactly at 1500 RPM, or can I start it a little earlier? And how long do I need to keep the clutch disengaged while rolling before I can end the log?

The issue is that when I take measurements in the third gear, my 'test track' will eventually become too short to fully accommodate the vehicle's rollout (without any curves or hills).

On the A4 highway, it also takes quite a while to slow down from 170 km/h, and then a hill starts, which certainly affects the speedometer reading.

Hi,

Of course, you can start the measurement whenever you like .
For a TDI engine, it's generally advisable to start increasing the RPMs from 1500 RPM.
When deploying, it typically reaches about half of the starting speed, and the rest is then interpolated.
The measurement will simply be slightly less accurate in the area where data is missing.

Best regards, Rainer.

@ Rainer
... Let it idle until it reaches half of its starting speed...


Hmm, did I make a mistake in my thinking there? or did you mean something completely different?

Äh sorry, dings. Need a vacation.
I meant half the speed between the start and end of the measurement.

If you ever look at a diagram showing the curve of traction force on a proper dynamometer, everything should become clear. When rolling out, the traction force initially drops sharply and then gradually decreases.
I'm going to bed now...

Best regards, Rainer.