I try to get isn of f30 n20 dme because i need to change dme but i try several times and said cannot get dme isn try to battery disconnect i do that but the same issue always

Some new DMEs in F series have more security. You can save time by trying boot mode.

Hi

I had the same problem, some DMEs have extra security, so you cannot read the ISN through OBD. You have to do it via boot made, that's the only way mate.

Thanks

I have the same problems, but I insist and the memso works at the time of writing the isn also happens the same problem, Today I made one then he asks to turn off the ignition, there I disconnect there ask to call I do not care, there I I turn on the ignition seconds later and the same thing makes the reading almost always right. But try more often than an hour pulls the password. Some just via Boot mode.

ISN boot mode should do the job if just follow the instructions.