mymustang

I was wondering if the "Calibration ID" and/or "Calibration Verification Number" will change if my car dealer updates the ECU software during a maintenance of the car?
I am looking for a simple way to find out if the car has been reprogrammed after a maintenance. I have a simple ODB reader so it is easy to read the vehicle info after a maintenance. If the car was previously tuned, it needs a retune in case the ECU has been overwritten by the car dealer...

David Young

It shouldn't change but, you will probably lose your tune . I would (you should too) return back to stock. Let your dealer do their thing and reinstall your tune after they are done.

mymustang

Hmmmm, are you sure? The "Calibration Verification Number" is a kind of md5, hash, checksum over the complete code. So i thought if 1 bit changes in the code, that number will change too... Only if the dealer flashes exact the same code into the ECU, the "Calibration Verification Number" shouldn't change. The "Calibration ID" is more like a version nr for the ECU code. That should also change if the code is a different version. Anyhow, That is how i understand it when i read the doc about the ODB fields. But i might be wrong for sure.
If you use a handheld tuner, then you can retune the car yourself. But i was thinking on getting a stage1 tune from an external tuner (there are no handheld tuners available for the 2018 yet ). So i need to go back there if the tune is overwritten