[VroomVroom]

Hello!
Because the ISTA does not offer any way to determine whether the mileage is correct, we have to look for other tools. Here is the instruction on how to check the mileage of BMW cars on your own.
At first more simple ways, later a little more complicated. Unfortunately the eXtratool program is poorly documented and without experience in BMW diagnostics it is difficult to see all its possibilities.
(For moderators please do not consider the program for advertising, I have nothing to do with the program and only want to help other. If you consider it necessary, the topic can be copied/moved to another section or deleted).

Start the program, select the item: BODY - check mileage.
After a couple minutes of testing the ECUs, you will see the following window with the results.
Some of my comments that will help to better understand the results of this test. Most of the ecus should have the same vin (your car vin) and mileage from the instrument cluster. Most ecus give mileage in km, but some ecus give mileage in meters. There may be differences in mileage between ecus within +_- 300 km (this is normal). It is possible that a few ecu will have FFFFFFF coding proof stamp CPS, this is also normal. The main thing is that there was no block with another car vin and the mileage on the blocks is more or less similar to the real one from the kombi unit.
This check works well on G series and badly on F (the fact that it is from G series bmw introduced this feature). When someone manipulate the mileage, it is impossible to change it in all ecus, and if you see differences in mileage, then either it was manipulated (here will help additional checks, about which later) or the seller put the used ecu to your car.
If there are any questions about your car, post a screenshot - we will figure it out together.

The next possible step is to check for the mileage of the automatic transmission and check the condition of the automatic transmission.
Open menu item: AT - Temperature History.
One of the unique features of the eXtratool program is the ability to view the entire history of the automatic transmission temperature mode. The history of overheating and the automatic transmission hour counter is not erased by programming and the only way to get rid of it is to replace the automatic transmission mechatronic (of course, no one does it before the sale). Works well on F and G series. It is possible to estimate whether there was overheating of the automatic transmission and time of work of the automatic transmission on each temperature range and total time of work.
Multiply the total running time by the average speed in your city and get the mileage. If the automatic transmission has not been changed, you will know the real mileage of the car.
In the next topics I plan to tell how to find out the time of work of the engine and transfer case also and as a result, knowing the motohours of the transfer case and engine and EGS, it is possible to find out the mileage correct or not.

[krolig]

BMW-explorer checks mileage in all ECUs with one button

[Bagum4uk]

BMW-explorer checks mileage in all ECUs with one button

It's not free software

[VroomVroom]

BMW-explorer checks mileage in all ECUs with one button

bmw explorer does not show egs temperature history log 
and cost much more money