FAQ & Troubleshooting

A: This usually means another program is using the COM port.

• Close Arduino IDE Serial Monitor if open
• Close any other programs using the port (PuTTY, Tera Term, etc.)
• Unplug and replug the USB cable
• Try a different USB port
• Restart the ESP32

A: Check these settings:

• Verify the baudrate matches your ESP32 firmware (common: 115200, 250000)
• Check USB cable is properly connected
• Ensure ESP32 is powered (LED should be on)
• Try different baudrates: 115200, 250000, 9600
• Check Device Manager (Windows) to confirm port is recognized

A: For WiFi connections:

• Ensure you're connected to the ESP32 WiFi network first
• Check IP address (default: 192.168.4.1)
• Check port (default: 82)
• Verify ESP32 is in Access Point (AP) mode
• Check firewall settings on your computer
• Try pinging the ESP32 IP address

A: Possible causes:

• ESP32 firmware may not be the CAN sniffer sketch - flash the correct firmware
• No CAN traffic on the bus - check if CAN bus is active
• MCP2515 not initialized - check serial monitor for errors
• Wrong CAN bus connection - verify CANH/CANL connections
• For testing without a car: connect 120Ω resistor between CANH and CANL

A: Check hardware connections:

• Verify all SPI pins are connected correctly (GPIO18→SCK, GPIO19→SO, GPIO23→SI, GPIO5→CS)
• Check power connection: 3V3 (NOT 5V!) to VCC
• Verify ground connection (GND to GND)
• Check for loose connections or bad jumper wires
• Try a different MCP2515 module if available
• Check serial monitor for specific error messages

• MCP2515 MUST be powered with 3.3V (ESP32's 3V3 pin)
• Using 5V will damage the module permanently
• Check power connection before testing

A: Use loopback mode:

• Connect a 120Ω resistor between CANH and CANL pins on MCP2515
• This simulates a terminated CAN bus
• Use the CAN simulator sketch to generate test messages
• Flash arduino/can_simulator/can_simulator.ino to ESP32

A: Try these solutions:

• Check log file: can_sniffer.log for error messages
• Reduce buffer size in Performance Tuning settings
• Close other resource-intensive applications
• Update Python and PyQt5 if running from source
• Use the crash report feature (About → Report Bug) to send details

A: Optimize performance:

• Increase serial baudrate (up to 1,000,000 bps)
• Reduce GUI update rate in Performance Tuning
• Increase buffer size for longer captures
• Use Serial connection instead of WiFi for better performance
• Close unnecessary applications

A: Check decoding settings:

• Verify correct vehicle database is loaded (Fiat CANB/CANC)
• Check if CAN ID exists in the database
• Enable debug output to see decoding details
• Verify database format is correct (byte addressing format)
• Some messages may not have decoders - this is normal

A: For license issues:

• Check internet connection (required for activation)
• Verify license key is correct (copy-paste to avoid typos)
• Check email for activation confirmation
• Ensure hardware hasn't changed significantly
• Contact support: contact.josko@gmail.com

A: Try these solutions:

• Update pip: python -m pip install --upgrade pip
• Use virtual environment: python -m venv venv
• Install packages one by one to identify problematic package
• Check Python version (3.8+ required)
• On Windows, try running as Administrator

A: Install USB drivers:

• CP210x drivers: Download from Silicon Labs
• CH340 drivers: Download CH340 drivers
• Check Device Manager (Windows) to see if device appears as "Unknown Device"
• Try different USB cable (some cables are power-only)
• Try different USB port

A: Check Arduino IDE setup:

• Install ESP32 board support in Arduino IDE
• Select correct board: Tools → Board → ESP32 Dev Module
• Select correct COM port
• Hold BOOT button while clicking Upload (some boards require this)
• Check Arduino IDE console for error messages
• Try different USB cable or port