My Duramax is under warrenty if the chip ain't in there but someone said it will show up on the ECM even if I take it out. Is this true or is there a way to get it off the ECM?

No, LLY ecm do not have a "History" Return to stock programming and they can't tell. The LMM ecm's DO have a history of the last 10 flashes but all previous models do not.

edit: Also, Welcome to DP, please fill out your sig w/ Year, Model, & Mods. It lets everyone know what you have and makes it easier to answer questions. Thanks. :)

I don't really know, but the reputable dealer I use said they can read it even on the LLY. Only because we were talking about it and I explained this to him. Then again it is a dealership. Just my two cents.

I don't really know, but the reputable dealer I use said they can read it even on the LLY. Only because we were talking about it and I explained this to him. Then again it is a dealership. Just my two cents.

Not possible the ECM for the LLY doesn't store a checksum which is used to check the changes that occur with program changes. I use EFI on my 04.5 and there is no way the dealer could tell, other than when they drove it on the road for a test:D.