If you can clarify:
The default PIN code for pairing the Bluetooth module is typically 0000 .
: This specific serial number is often required during the software installation process to "handshake" with diagnostic programs like Autocom 2020.23 or Delphi DS150E. Hardware Key
Many users look for this specific serial number (3555) because it is known to work well with unofficial diagnostic software suites commonly found on AliExpress and other marketplaces.