Adapt Odometer/Speedometer: How-to Guide

Hello,

'Can anyone help me and tell me how to recalibrate the mileage or speedometer on my Ibiza 6L Cupra TDI? Since I switched from winter to summer tires, it's showing about 3% less distance. As a result, the average fuel consumption displayed on the onboard computer is higher, and the speedometer is only showing about 1% more than the actual speed (measured with GPS), so it's extremely accurate! When the speedometer shows 100 km/h, the actual speed is 99 km/h. I bought the car in the winter and this is the first time I'm using the original summer tires.'

{Combination instrument}

ECU coding.

Select STG 17 (combination instrument).
ECU coding -> Function 07.

??xxx: Optional extras / Additional features.

+01 - Brake pad wear indicator active.
+02 - Seat belt warning indicator active.
+04 - Windshield washer fluid level warning indicator active.

xx?xx: Country selection.

0 - Germany (D)
1 - Europe (EU)
2 - USA (US)
3 - Canada (CDN)
4 - United Kingdom (UK)
5 - Japan (JP)
6 - Saudi Arabia (SA)
7 - Australia (AUS)

xxx?x: Engine variant.

3 - 3-cylinder
4 - 4-cylinder

xxxx?: Number of impulse waves.

1 - 3662/23984
2 - 3770/24016
3 - 3770/24324
4 - 3825/24292
5 - 3880/24016
6 - 3960/24292
7 - 3960/24324
8 - 4021/23984


Source: http://de.openobd.org

'Today, I adjusted the values from 1 - 3662/23984 (=0.153) to 2 - 3770/24016 (=0.157), which represents a difference of almost 3% (which is my deviation). Unfortunately, nothing has changed. In fact, I think the deviation might have even increased. Or am I mistaken? I simply want the control unit to receive a reasonably accurate speed signal so that the speedometer displays the correct speed, the fuel consumption is calculated correctly, etc.'

Please help me...

SeatLeon wrote:

I simply want the engine control unit to receive a reasonably accurate speed signal so that the speedometer displays the correct speed, the fuel consumption is calculated correctly, etc.

SeatLeon wrote:

... so he is extremely precise!

SeatLeon wrote:

The speedometer is only showing about 1% of the actual speed.

Is it accurate now, then? Have you ever calculated anything and compared the consumption rates?

It's not about the accuracy of the speedometer display itself, but about whether the control unit receives correct speed signals. For example, if the speedometer shows 100, the GPS shows 99, but the control unit reports only 97. The deviation of the speedometer reading (upwards) from the speed reported by the control unit is predetermined and should be that way. However, the odometer should not run ahead or lag behind, but should be as accurate as possible. And it was the same with the winter tires. Now, it's counting about 3% less than the actual distance traveled (instead of 1000 km, it only shows 970 km).