(Solved) V7.0 BMW Multi Tool failed at the security access

Recent my BMW Multi Tool reported a problem, saying “failed at the security access” when I was programming a new key. I contacted my supplier and their technician helped me solve it smoothly.

Here is the solution:

 

  1. Add key obd;
  2. Cas3+ encrypt version -> no need to update CAS (no need for key cycling)
  3. Cas ISTAP4x version -> need to update cas (no need for key cycling)
  4. Lost key obd;
  5. Cas3+ encrypt version -> no need to update CAS (need to cycle key UPTO 16 times)
  6. Cas ISTAP4x version -> need to update CAS (need to cycle key UPTO 64 times)
  7. Add key dump method (lost or working key);
  8. Cas3+ encrypt version -> need to write back to CAS (needs either -working key / known ISN / ECU dump / or cycle UPTO 16 times)
  9. Cas ISTAP4x version -> no need to write back to cas (needs either -working key / known ISN / ECU dump / or cycle UPTO 64 times)
  10. So the 64 cycle is really to save you having to downgrade the CAS but you still need to manually read the CAS for this option. For me this is still the best way as there is no way I would downgrade the CAS (unless you made it very clear what this meant to the tool).

 

If you have ever encountered this problem, hope this info can help you.

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