While trying to add a new key to a BMW G31 equipped with a BDC2 system using the Xhorse VVDI2 and BMW BDC2 adapter, the process could not move past the “read coding” step. The VVDI2 software displayed an error message indicating an unknown coding version, preventing further key programming.
After investigation, the root cause was identified as corrupted or missing CAFD coding data in the BDC module. The vehicle was running a 2021 software version, but the required coding file (CAFD) was missing, specifically from software version S15A-21-11-560. Because of this, VVDI2 could not recognize or accept the coding data.
Solution
The BDC module was reinstalled back into the vehicle, and the coding data was repaired through the OBD2 port using the X-Diag program with a Launch adapter. This step restored the missing CAFD data. Although manual CAFD import normally requires a dedicated BMW coding program, once the correct coding was written back to the BDC, the system became readable again.
User report:
After repairing the BDC coding via OBD, the VVDI2 software accepted the updated coding without any errors. Key programming was then completed successfully with no further issues. In the end, the problem was fully resolved, and VVDI2 handled the corrected BDC data smoothly.
This case highlights the importance of checking BDC coding integrity when encountering “unknown version” errors during BMW BDC2 key programming.
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