Interesting article - How A Car Company Decides If It's Going To Warranty Your Modified Car

[B33tl3]

 

This one has some data from Ford but it was an interesting read that has some things that apply to other brands.

https://jalopnik.com/how-a-car-company-decides-if-its-going-to-warranty-your-1821736111

 

I always wondered they could tell if you flashed the PCM. 

"The IDS (Integrated Diagnostic System) software that Ford technicians use for diagnostic has a few features built into to detect if the car’s software itself has been modified. One such feature is called the ignition counter, which records the number of engine starts since the engine computer was last reflashed. This number should be fairly high for any unmodified car, but it resets to zero when an aftermarket tune is flashed."

 

[davester]

Yes, I believe GM, at least for the recent Duramax's, but probably for all their vehicles, at least track how many times the PCM has been flashed, and likely tracks other stuff as well for each flash.

[Colossus]

Correct.