Troubleshooting
Board Not Detected
Feather boards: Double-press the Reset button to enter the UF2 bootloader, then retry the upload command.
ESP32 boards: Hold the BOOT button during upload if auto-reset does not work.
No Serial Output
- Ensure the Serial Monitor is set to 115200 baud
- Check that
enablePrintis set totrue - Verify the USB cable supports data (not charge-only)
CAN Communication Errors
- Check termination: Make sure you cut/removed the onboard 120 Ohm termination resistor
- Check wiring: CAN-H and CAN-L must not be swapped
- Check baud rate: The vehicle uses 500 kbit/s — this is set automatically by the firmware
FSD Not Activating
- Verify you have an active FSD subscription or purchase
- Check that "Traffic Light and Stop Sign Control" is enabled in Autopilot settings (unless using
BYPASS_TLSSC_REQUIREMENT) - Open the Serial Monitor and check if the handler output shows
FSD: 1 - Verify you selected the correct vehicle variant in
sketch_config.h - HW4 on FSD v13: Make sure you compiled with
HW3, notHW4
Build Errors
Board/driver mismatch
If the PlatformIO -e environment doesn't match the DRIVER_* define in sketch_config.h, the build will fail with a clear error. Make sure they match.
Missing libraries
- Feather RP2040: Install MCP2515 by autowp in Arduino IDE
- Feather M4: Install Adafruit CAN in Arduino IDE
- ESP32: No additional libraries needed
Native test compilation fails (Windows)
Install MinGW-w64 GCC:
winget install BrechtSanders.WinLibs.POSIX.UCRT
Restart your terminal so gcc is on PATH.
Speed Profile Not Changing
- Make sure you're adjusting the follow distance on the steering wheel stalk, not cruise speed
- Check Serial Monitor output to see if the distance value changes
- Verify the correct vehicle variant is selected (HW4 has 5 levels, HW3 has 3)