GM 17+ ECU Unlock

[MrSquiggles]

Screenshot 2026-05-11 131031.png

I finally got the order to go through for the GM 2017+ ECU Unlock. It said I was supposed to receive an email, but it's been several hours and no email. I launched the Update Agent and plugged in the i3, both say they are fully updated and wouldn't download anything. Am I supposed to get a link or .exe emailed to me to install on the device?

Order #HLY1506897

Thanks!

[MrSquiggles]

Screenshot 2026-05-11 131332.png

[06MonteSS]

...2017+ vehicles require a special unlock sequence - so the first thing is to make sure that you register your programmer with Diablosport - https://www.holley.com/support/registration/ ----- Then you need to run the Update Agent program on your pc/laptop to update your programmer... ----- Then connect to your vehicle and select the preset canned generic tunes to install for the ECM... ----- Then what will happen is, when you go to install the preset generic tunes for the first time, the install will fail and the programmer will give you an error message: "Read failed, ECU rejected seed request (locked?)" ----- So disconnect from the vehicle, and then wait about 10 minutes, and then connect to your pc/laptop again and run the Update Agent program again and the programmer will update itself with the ECM unlock.... ----- Then you can go back to the vehicle and you will be able to select/install the preset generic tunes following my instructions above...

So...

1. Register the programmer - https://www.holley.com/support/registration/

2. Run Update Agent

3. Select a preset canned tune to install, and then Apply/Install Tune

4. Install will fail with message "Read failed, ECU rejected seed request (locked?)" -- or -- "One or more ECU's needs an update"...

5. Run the Update Agent a second time (the ecu unlock will install)

6. Connect back to vehicle and Select/Install the preset canned tunes...

[mikel]

its generally instant. Did you try tuning the vehicle again?