Tesla FSD CAN Bus Enabler

Background: This project was inspired by @mikegapinski and his Tesla Android Diagnostic Tool, which enables FSD in regions where it is not yet fully available. I was interested in his product but was put off by the long delivery time and cost. Around the same time I came across a GitLab repository by Starmixcraft that took a simpler, DIY approach. The original repo appeared to be deleted but has since moved to gitlab.com/Tesla-OPEN-CAN-MOD/tesla-fsd-can-mod (the old Starmixcraft URL now redirects there). I picked up the last available version of that project and have been building on it — adding support for more boards and working toward feature parity with commercial solutions. The goal is not to undermine @mikegapinski's work (if you want a polished, plug-and-play product, go buy his tool), but to keep a DIY alternative available for the community.

Project Structure

boards/
├── ESP32_MCP2515/       # ESP32 + external MCP2515 SPI module
│   └── ESP32_MCP2515.ino
├── ESP32S3_TWAI/        # ESP32-S3 with built-in TWAI (CAN) + transceiver (e.g. SN65HVD230)
│   └── ESP32S3_TWAI.ino
├── FeatherM4CAN/        # Adafruit Feather M4 CAN Express (ATSAME51 + MCP25625)
│   └── FeatherM4CAN.ino
├── RP2040CAN/           # Adafruit Feather RP2040 CAN (MCP25625)
│   └── RP2040CAN.ino
└── UNO_MCP2515_CAN/     # Arduino UNO + MCP2515 module
    └── UNO_MCP2515_CAN.ino

Each board variant lives in its own directory (required by the Arduino IDE). Pick the sketch that matches your hardware.

📌 Prerequisites

You must have an active FSD package on the vehicle — either purchased or subscribed. This board enables the FSD functionality on the CAN bus level, but the vehicle still needs a valid FSD entitlement from Tesla.

If FSD subscriptions are not available in your region, you can work around this by:

1. Creating a Tesla account in a region where FSD subscriptions are offered (e.g. Canada).
2. Transferring the vehicle to that account.
3. Subscribing to FSD through that account.

This allows you to activate an FSD subscription from anywhere in the world.

🛠️ What It Does

This firmware intercepts specific CAN bus messages to enable and configure Full Self-Driving (FSD). It supports multiple boards — from Adafruit Feathers with MCP25625, to ESP32 with external MCP2515 modules, to ESP32-S3 using its built-in TWAI (CAN) controller. Additionally, ASS (Actually Smart Summon) is no longer restricted by EU regulations.

🚗 Core Function

• Intercepts specific CAN bus messages
• Re-transmits them onto the vehicle bus

🧠 FSD Activation Logic

• Listens for Autopilot-related CAN frames
• Checks if "Traffic Light and Stop Sign Control" is enabled in the Autopilot settings Uses this setting as a trigger for Full Self-Driving (FSD)
• Adjusts the required bits in the CAN message to activate FSD

⚙️ Additional Behavior

• Reads the follow-distance stalk setting
• Maps it dynamically to a speed profile

⚙️ HW4 - FSD V14 Features

• Approaching Emergency Vehicle Detection

Supported Hardware Variants

Select your hardware variant via the #define HW directive in the sketch for your board:

Define	Target	Listens on CAN IDs	Notes
LEGACY	HW3 Retrofit	69, 1006	Sets FSD enable bit and speed profile via follow-distance stalk
HW3	HW3 vehicles	1016, 1021	Adds speed-offset control via follow-distance
HW4	HW4 vehicles	1016, 1021	Extended speed-profile range (5 levels)

Note: HW4 vehicles on firmware older than 2026.2.3 do not use FSDV14. If your vehicle is on an earlier firmware version, compile with HW3 even if your vehicle has HW4 hardware.

How to Determine Your Hardware Variant

• Legacy — Your vehicle has a portrait-oriented center screen and HW3. This applies to older Model S and Model X vehicles retrofitted with HW3.
• HW3 — Your vehicle has a landscape-oriented center screen and HW3. You can check your hardware version under Controls → Software → Additional Vehicle Information on the vehicle's touchscreen.
• HW4 — Same as above, but the Additional Vehicle Information screen shows HW4.

Key Behaviour

• FSD enable bit is set when "Traffic Light and Stop Sign Control" is enabled in the vehicle's Autopilot settings.
• Speed profile is derived from the scroll-wheel offset or follow-distance setting.
• Nag suppression — clears the hands-on-wheel nag bit.
• Debug output is printed over Serial at 115200 baud when enablePrint is true.

CAN Message Details

The table below shows exactly which CAN messages each hardware variant monitors and what modifications are made.

Legacy (HW3 Retrofit)

CAN ID	Hex	Name	Direction	Mux	Action
69	0x045	STW_ACTN_RQ	Read only	—	Read follow-distance stalk position → map to speed profile
1006	0x3EE	—	Read + Modify	0	Read FSD state from UI; set bit 46 (FSD enable); write speed profile to bits 1–2 of byte 6
1006	0x3EE	—	Read + Modify	1	Clear bit 19 (nag suppression)

HW3

CAN ID	Hex	Name	Direction	Mux	Action
1016	0x3F8	—	Read only	—	Read follow-distance setting → map to speed profile
1021	0x3FD	—	Read + Modify	0	Read FSD state from UI; calculate speed offset; set bit 46 (FSD enable); write speed profile to bits 1–2 of byte 6
1021	0x3FD	—	Read + Modify	1	Clear bit 19 (nag suppression)
1021	0x3FD	—	Read + Modify	2	Write speed offset to bits 6–7 of byte 0 and bits 0–5 of byte 1

HW4

CAN ID	Hex	Name	Direction	Mux	Action
1016	0x3F8	—	Read only	—	Read follow-distance setting → map to speed profile (5 levels)
1021	0x3FD	—	Read + Modify	0	Read FSD state from UI; set bit 46 (FSD enable); set bit 60 (FSD V14); set bit 59 (emergency vehicle detection)
1021	0x3FD	—	Read + Modify	1	Clear bit 19 (nag suppression); set bit 47
1021	0x3FD	—	Read + Modify	2	Write speed profile to bits 4–6 of byte 7

Hardware Requirements

One of the following boards (or a compatible alternative):

Board	CAN Interface	Notes
Adafruit Feather RP2040 CAN	MCP25625 (onboard)	Uses board-defined PIN_CAN_* constants
Adafruit Feather M4 CAN Express	MCP25625 (onboard)	ATSAME51, requires boost enable (PIN_CAN_BOOSTEN)
ESP32 + MCP2515 module	MCP2515 (external SPI)	Default: CS=GPIO5, INT=GPIO4. Check module crystal (8 vs 16 MHz)
ESP32-S3 + CAN transceiver	Built-in TWAI controller	Only needs a transceiver (e.g. SN65HVD230), no MCP2515
Arduino UNO + MCP2515 module	MCP2515 (external SPI)	Default: CS=D10, INT=D2. Check module crystal (8 vs 16 MHz)

All pin assignments are configurable at the top of each sketch. CAN bus connection to the vehicle must run at 500 kbit/s.

Installation

1. Install the Arduino IDE

Download from https://www.arduino.cc/en/software.

2. Install the Board Package

Open File → Preferences and add the appropriate URL to Additional Board Manager URLs, then install the board package via Tools → Board → Boards Manager:

Board	Board Manager URL	Package to install
Adafruit Feather RP2040 CAN	https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json	Raspberry Pi Pico/RP2040
Adafruit Feather M4 CAN Express	https://adafruit.github.io/arduino-board-index/package_adafruit_index.json	Adafruit SAMD Boards
ESP32 / ESP32-S3	https://espressif.github.io/arduino-esp32/package_esp32_index.json	esp32 by Espressif
Arduino UNO	(built-in)	Arduino AVR Boards

3. Install Required Libraries

For MCP2515-based boards (all except ESP32-S3 TWAI), install the following library via Sketch → Include Library → Manage Libraries…:

• MCP2515 by autowp — CAN controller driver (mcp2515.h)

The ESP32-S3 TWAI variant uses the built-in ESP-IDF TWAI driver and requires no additional libraries.

4. Select Your Hardware Target

Near the top of the sketch for your board, change the HW define to match your vehicle:

#define HW HW3  // Change to LEGACY, HW3, or HW4

5. Upload

1. Connect your board via USB.
2. Select the correct board and port under Tools.
3. Click Upload.

6. Wiring

The recommended connection point is the X179 connector:

Pin	Signal
13	CAN-H
14	CAN-L

Connect your board's CAN-H and CAN-L lines to pins 13 and 14 on the X179 connector.

The recommended connection point for legacy Model 3 (2020 and earlier) is the X652 connector if the vehicle is not equipped with the X179 port (varies depending on production date):

Pin	Signal
1	CAN-H
2	CAN-L

Connect your board's CAN-H and CAN-L lines to pins 1 and 2 on the X652 connector.

Important: If your board or CAN module has an onboard 120 Ω termination resistor, cut or remove it. The vehicle's CAN bus already has its own termination, and adding a second resistor will cause communication errors. This applies to Adafruit Feather CAN boards and many MCP2515 modules.

Speed Profiles

The speed profile controls how aggressively the vehicle drives under FSD. It is configured differently depending on the hardware variant:

Legacy (HW3 Retrofit)

Because the Legacy variant transmits follow distance differently, it uses a speed offset value (in km/h) to select the profile:

Speed Offset (km/h)	Profile
28	Chill
29	Normal
30	Hurry

HW3 & HW4 Profiles

Distance	Profile (HW3)	Profile (HW4)
2	⚡ Hurry	🔥 Max
3	🟢 Normal	⚡ Hurry
4	❄️ Chill	🟢 Normal
5	—	❄️ Chill
6	—	🐢 Sloth

Serial Monitor

Open the Serial Monitor at 115200 baud to see live debug output showing FSD state and the active speed profile. Disable logging by setting enablePrint = false.

My Setup

I'm personally using an Adafruit Feather M4 CAN Express with ATSAME51. It was easy to source, has an onboard MCP25625 CAN controller, and is a great fit for this application.

Roadmap

This fork aims to expand on the original project:

• Installation guide — a step-by-step guide with photos covering wiring, flashing, and verifying the setup.
• Proper connector and power — replace the current jumper-wire setup with a proper connector cable like the EnhAuto Tesla Gen 2 Cable, and connect to the same diagnostic port that the EnhAuto S3XY Commander uses — providing both CAN bus data and power through a single connection point. This is a similar approach to what @mikegapinski uses with his Tesla Android Diagnostic Tool.
• Enclosure — a 3D-printable or off-the-shelf enclosure to protect the board and make the installation clean and permanent.
• More supported boards — e.g. Teensy 4.x (FlexCAN), STM32 + MCP2515.
• New features — contributions and ideas are welcome via issues and pull requests.

Warning

This project is for testing and educational purposes only. Sending incorrect CAN bus messages to your vehicle can cause unexpected behavior, disable safety-critical systems, or permanently damage electronic components. The CAN bus controls everything from braking and steering to airbags — a malformed message can have serious consequences. If you don't fully understand what you're doing, do not install this on your car.

Disclaimer

Use this project at your own risk. Modifying CAN bus messages on a vehicle can lead to unexpected or dangerous behavior. The authors accept no responsibility for any damage to your vehicle, injury, or legal consequences resulting from the use of this software. This project may void your vehicle warranty and may not comply with road safety regulations in your jurisdiction. Always keep your hands on the wheel and stay attentive while driving.

License

This project is licensed under the GNU General Public License v3.0 — see the GPL-3.0 License for details.