So I thought the CVN gets changed every time the tune gets modified and written???

[thesubfloor]

Turns out that may not be the case unless I'm completely missing something very obvious.

So I live in the glorious (and I use that term very loosely) state of California and like everyone else here who uses HP Tuners I was concerned about the recently imposed law that compares the CVN in the tune to the original. If it doesn't match then the emissions test will fail citing "Modified Software".

Having just bought a 2011 Grand Sport and not knowing if it had ever been tuned, I went through the steps of checking for myself.

According the the GM website, the original CVN is 3889:

1.jpg

And according to the tune it's also 3889:

2.jpg

So far so good, right? Nope...

Just for fun I checked the original CVN for my 2007 race car which has been flashed countless times. According to GM the current, on file CVN is 5739. I say current because according to them it had been reflashed two more times at the dealership:

3.jpg

And here's where the oddity happens. According to my current tune the CVN is also 5739:

4.jpg

So, what gives? Anybody got any ideas why the CVN hasn't changed despite everything I've read about HP Tuners saying that it should be different.

[blindsquirrel]

Making changes to the tune file only changes the CVN for the segment that contains the bits you changed.

Try this: Take a file and change just one something in one of the tabs and save as a new file. Then compare Details of the new file with old file. One of the segments will show a different CVN, the one that's different is the one that contains the setting you changed. The CVN for the other segments will still be the same because nothing was changed in them. CalIDs/CVNs are nothing to do with the counter that shows if/how many times it's been flashed.

[thesubfloor]

Making changes to the tune file only changes the CVN for the segment that contains the bits you changed.

Try this: Take a file and change just one something in one of the tabs and save as a new file. Then compare Details of the new file with old file. One of the segments will show a different CVN, the one that's different is the one that contains the setting you changed. The CVN for the other segments will still be the same because nothing was changed in them. CalIDs/CVNs are nothing to do with the counter that shows if/how many times it's been flashed.

As I stated above, I figured I might have been missing something obvious and that was definitely it.

Thanks for clarifying.