Seems odd, especially when most programming doesn't require you to change every segment.
vehicle calibration
- Thread starter Tired Old Man
- Start date
Seems odd, especially when most programming doesn't require you to change every segment.
My question is---- is it possible that this is a hidden thing that is in the ECM and EFI doesn't address the situation that GM is now checking???????
While it is possible, it's not likely. Normally those numbers are check sums. You can think about them like signatures.
Each "byte" in a computer file can have a value of 0-255.
The simplest checksum would be to just add each byte's value together. If you change one byte, the answer will be different. But they aren't that simple in real life usually.
Sometime they rotate a bit each time so that if you swap two bytes for each other, the checksum comes out different. There are other methods as well.
But it seems the checksum is 2 bytes (16x16x16x16), or 65536 different possibilities. This can only be certain nothing changed if the change was not intended to defeat the checksum.
Last edited:
When you do I'd apprecate a PM or a post so that everybody can read and weep
On the LMM GM now have much smarting programming history tracking. On the 05's this was not the situation, whilst they can see all the part numbers and CVN for each segment with a TechII they can't see what was in it in the past, only what is installed now.
On your Kodiak, if you read the stock tune and modified it from there then your Part numbers will match but the CVN's will be wrong, GM check the CVN's to those listed on the CalID website. If the tune is put back to stock then the CVN's will match, only the LMM keeps a history of previously programmed part numbers/CVN's.
It is possible that depending where you got your Kodiak from (ie coach builder) that the CVN's were never "stock" to begin with.
Cheers,
Ross (using Cindy's login)
On your Kodiak, if you read the stock tune and modified it from there then your Part numbers will match but the CVN's will be wrong, GM check the CVN's to those listed on the CalID website. If the tune is put back to stock then the CVN's will match, only the LMM keeps a history of previously programmed part numbers/CVN's.
It is possible that depending where you got your Kodiak from (ie coach builder) that the CVN's were never "stock" to begin with.
Cheers,
Ross (using Cindy's login)
I will have to generate a fresh Tech2 flash for Casper to confirm some more.
But at this point, I'd say this:
Casper was used to test many different ECM tuners, and has been flashed hundreds of times using EFILive.
Any of the tuners I used might have failed to "return to stock" 100%.
More testing is needed.
But at this point, I'd say this:
Casper was used to test many different ECM tuners, and has been flashed hundreds of times using EFILive.
Any of the tuners I used might have failed to "return to stock" 100%.
More testing is needed.
Is There a way that one can check w/EFI that the #'s match before GM finds out and black lists you????
This is the stock tune that was in the truck when I got it, on comparison w/EFI all are the same from 2 different thumb drives and 2 different hard drives. 4 different locations.
Guess what kids?
GM is lying.
If the dealer reflashes your truck with a Tech2, it won't match either.
So all that CVN proves is that SOMETHING might have reflashed the truck, even a Tech2 with Factory GM Calibrations.
This is truly bizarre.
But EFILive's CVN's matches what a Tech2 CVN is. EFILive doesn't change it.
GM is lying.
If the dealer reflashes your truck with a Tech2, it won't match either.
So all that CVN proves is that SOMETHING might have reflashed the truck, even a Tech2 with Factory GM Calibrations.
This is truly bizarre.
But EFILive's CVN's matches what a Tech2 CVN is. EFILive doesn't change it.
Now I need to find something that is hard to find:
A 100% unflashed stock 2005-2006 Duramax. Not even dealer updates.
Then we read the screen, then update the truck using a Tech2, then check again.
My guess is we will find that any flashing (even dealer updates) will change the numbers.
A 100% unflashed stock 2005-2006 Duramax. Not even dealer updates.
Then we read the screen, then update the truck using a Tech2, then check again.
My guess is we will find that any flashing (even dealer updates) will change the numbers.