ECU security code

[Bobreme]

Hi I've got a Corsa that needed a replacement ECU after having the original repaired unsuccessfully, I purchased an ECU kit with BCM but unfortunately after fitting the ECU it won't accept the security code. I read a post on here from a couple of years ago about being able to read the code, is this still possible and what are people now using? I have got opcom and all the vin numbers are correct