Another Newbie question...GM part number to OS correlation?

Is there a way to know what part number I should be looking for when I'm looking for a used ECM?

I'm looking for a ECM that was originally running a L83/T87. I have determined this combo was available in 2016.

In the tune repository I found a file labelled 1461607566. When I open that file I can see it is OS 12672612. It has the engine/transmission combo I want to use.

First off why is the file labelled with the 146* number? Is there significance to that label?

I have also determined there are web sites I can go to if I know a vehicles VIN number I can determine what engine/transmission it came equipped with.

I can then go to an auction site for example and find a used ECM listing that includes a VIN number and could determine if said ECM is already configured with my preferred combo.

My problem is most listings just don't include the VIN number but rather just a ECM part number like 12670744 as an example.

So how can I be sure I'm buying an ECM I can use based on just a GM part number?

In GM-speak, a Service Number identifies the hardware.

A Part Number is a specific Service Number after it's programmed with a specific calibration. Since they are re-flashable, part number is mostly not useful. If you have two different year/make/models that both call for the same Service Number, that one Service Number can be programmed with the calibration for either application. You cannot use HP Tuners to flash a repository file to a new/used GM Gen 4/Gen 5 ECM. HPT does not write all of the segments. To change the OS on one of these ECMs you need dealer-type tools, a GM MDI or a suitable J2534 passthru device and a GM SPS subscription. However, there are lots of folks out there selling used ECMs that will program them to the VIN you specify.

Go look up your year/make/model (or, preferably, look up by VIN), find the Service Number, then go look for one of those. If it's the same Service Number, and you have the right tools to do a proper reprogramming, it doesn't matter if it's a different Part Number.

The numbers in HPT's repository files are just like how this thread is number '102639'. Has nothing to do with the content of the repository file (or this thread), it's just a sequential number.

http://www.gmpartsdirect.com/ (one of many using the same database) has a VIN-based search where you can find what parts a given VIN uses. Just copy the VIN from a tune file, paste it into the search box, and go to Electrical, then Powertrain Control.

Both of these are 2016 and both have OS 12672612

2016 L86 8L90 & T87
Attachment 129520

2016 L83 6L80 & T43
Attachment 129521
Wrong photo. Removed. Correct one below.

I'd bet the tune you got from the repository used the same service number as these.

Ignore that E90 above. Wrong photo.

2016 L83 6L80 & T43
Attachment 129522

Thanks both of you!

So if I understand correctly, as long as I have the correct OS I can segment swap all the relevant information into the ECM?

No, do not segment swap. Start with having it correctly programmed with the correct tools using a VIN that matches the hardware. There are two segments HP Tuners cannot read or write.