BMW Multi Tool V7.0 The solution towards eorror‘failed at the security access ’ when make the key
BMW Multi Tool V7.0 The solution towards eorror‘failed at the security access ’ when make the key
BMW Multi Tool V7.0 The solution towards eorror‘failed at the security access ’ when make the key
Some users would meet this problem when make the key,we guess users might go to the original local dealer to upgrade the CAS to the newest version which cause the problem.The solution is different under different conditions,here is one of the client's sharing in BBS might help you:
add key obd:
cas3+ encrypt version -> no need to update CAS (no need for key cycling)
cas ISTAP4x version -> need to update cas (no need for key cycling)
lost key obd:
cas3+ encrypt version -> no need to update CAS (need to cycle key UPTO 16 times)
cas ISTAP4x version -> need to update CAS (need to cycle key UPTO 64 times)
add key dump method (lost or working key);
cas3+ encrypt version -> need to write back to CAS (needs either -working key / known ISN / ECU dump / or cycle UPTO 16 times)
cas ISTAP4x version -> no need to write back to cas (needs either -working key / known ISN / ECU dump / or cycle UPTO 64 times)
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's s no way I would downgrade the CAS (unless you made it very clear what this meant to the client)