Credit goes to PeteS160plus
Orignal video https://www.youtube.com/watch?v=oGeMK6LvQck


So I got a ECU and to my supprise when trying to read it I got a $0537 error.
At first I tried the brute force method but 3 days in something went wrong with the software and it stopped its self before finishing.
Not wanting to start over again and because the ECU was basically junk other wise I tried the method shown in the video and it worked with out letting the smoke out.


Here are the instructions.
Click image for larger version.  Name: P01 LS1B Unlock.jpg  Views: 862  Size: 1.10 MB  ID: 22864

Earth the pin point I have marked in red at the top of the image for 1 second as you power the ECU On.
You have about 10 seconds before the ECU will respond that its in recovery mode.
It will read and write using the stock GM Keys after that.

I was unsure what was going to happen so I videoed it to try and capture the smoke if it came out as can be seen here.
https://youtu.be/BJxZvzSC0B8