Many tools can read Opel EDC16C39 ECU over OBD, including Foxflash. Foxflash also read it on bench.
On bench you read eeprom and you can see the immo code in hex format or get code from 3rd party decoder. It’s not a bad solution, just takes more time.
For example:
Opel Zafira B edc16c39 eeprom bench reading, to extracting pin code for key learning.
Foxflash Opel EDC16C39 5
