Here is the easy steps to read BMW CAS3 ISN by using CGDI Prog BMW MSV80 key programmer via OBD.
Connect CGDI Prog key programmer with laptop and vehicle from obd2tool.com
Open key programming tool CGDI Prog software on desktop
Select BMW Read DME ISN function
Please remove the key from the ignition
The CAS ISN data was read successfully.
How to use CGDI Prog to Program BMW CAS3 key by OBD