EOBD + Facile + Serial Code Fix Context (assumed) You’re working with an EOBD/OBD-II adapter and the Facile (e.g., "ScanXL" / "Facile" style) software/device that communicates over a serial interface (USB-to-serial or TTL serial). The problem is a communication or serial code error between the adapter and Facile software — symptoms: no connection, garbled data, wrong protocol selection, or device not recognized. Quick checklist (diagnose first)
Physical connections
Confirm OBD-II adapter is fully seated in vehicle port and powered (vehicle ignition ON or engine running as required). If using USB serial, try different USB port or cable and avoid passive USB hubs.
Driver / Device recognition
On Windows: check Device Manager for the correct COM port (e.g., FTDI/CH340/Prolific). Install/update drivers for the chip. On macOS/Linux: run ls /dev/tty.* or dmesg / journalctl to confirm device node (e.g., /dev/ttyUSB0, /dev/tty.SLAB_USBtoUART). Ensure no other program is holding the serial port.
Serial settings
Common settings for many ELM327-style adapters: 38400 or 115200 baud (some use 9600). Default ELM327 is often 38400; clone devices vary. Typical serial parameters: 8 data bits, no parity, 1 stop bit (8N1), no flow control. In Facile settings, set the COM port and match baud rate. If unsure, try 115200 → 38400 → 9600 sequence. eobd+facile+serial+code+fix
Protocol & Adapter mode
Some adapters auto-detect protocol; others require manual selection. If auto fails, force the correct protocol (ISO9141-2, KWP2000, CAN, J1850 VPW/PWM). With CAN-only adapters, OBD-II modes for older vehicles won't work.
AT command check
Use a serial terminal (e.g., PuTTY, screen, minicom) to send ATZ (reset) and ATI (identify). Expected responses: adapter reset message and adapter type (e.g., ELM327 v1.5). If garbled responses, try different baud rates and line endings (CR vs CR+LF).
Common adapter issues & fixes