: The ignition is turned off, or the ELM327 clone hardware uses a faulty v2.1 firmware chip that does not support older K-Line protocols.
Official software versions typically come with support, updates, and ensure full functionality. Using modified or cracked versions might result in limited functionality, and users usually don't receive updates or support. ScanMaster-ELM v2.1 build 771 Incl. Keygen.15