Question - Swapping ECU between similar vehicles


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I have a limeswap-modified ECU on the one '03 Sierra that I plan to sell.

Realized a couple of days ago that rather than just give that tune away, I could keep that, and swap it to the new truck (same year, same model, same engine - different VIN, of course). Would save me the trouble/expense of getting it redone, if I could swap it.

Only difference between the two is the Quadrasteer, 4x4 and rear axle.

I do have the Tech2, so I should be able to make any needed changes (although most -- if not all -- of what's different, s/b in the BCM, IIRC).

Anything I need to worry about here, or just swap with impunity?

Appreciate responses, and apologies if this was 'obvious' - just wanted to check.


Silver Supporter
I would think you'd be able to just swap it and change the VIN, rear axle ratio...not sure if the 4x4 would be an issue. You could hit up Jeremy and ask.


Swapping the VIN in the PCM via the Tech 2 probably would wipe out the existing tune and bring it back to stock. You should be able to use it with just a security relearn. The other options are controlled by the BCM and other modules so no worries there. Only thing though is the gearing and speedo output.


Lifetime VIP Supporter
Appreciate the info, guys. I actually thought it might be plug-n-play - what I'm hearing here suggests that there would actually be some changes. I'll research this a bit online and perhaps drop Jeremy a line, like @Matt suggested.

In light of the answers...glad I asked! :tiphat:

It's gonna be at least a few days until I'm ready to swap - but I'll try and remember to come back here and detail what had to be done to make it 'successful'. Since the two trucks are same year / model / motor, I don't see the point in sending out a *third* ECM to be tuned! LOL

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