TruckDevil

April 4, 2026 ยท View on GitHub

A framework for interacting with and assessing ECUs that use J1939 for communications on the CAN bus.

Requirements

Hardware

The recommended CAN transceiver is the Macchina M2 (Under-the-Dash).

However, python-can is used so any supported CAN interface (e.g. SocketCAN) will work. An OBD-II to J1939 deutsch 9-pin adapter or splitter may also be needed, available on Amazon.

Software

Python 3 is required.

Additional software is required to flash the m2_sketch firmware to the M2, if used (see Installation).

Installation

> git clone https://github.com/LittleBlondeDevil/TruckDevil.git
> cd TruckDevil
> python -m venv venv
> venv\Scripts\activate        # Windows
> source venv/bin/activate     # Linux / macOS
> pip install -r requirements.txt

M2 (if used)

  • Follow the first 3 steps included in the M2 Arduino IDE Quick Start guide
    • Install the Arduino Desktop IDE
    • Install the Macchina M2 Board Configuration
    • Install drivers
  • Download and include due_can and can_common libraries from collin80 into IDE 
    Sketch > Include Library > Add .Zip Library...
  • Upload m2_sketch.ino to the M2
    • Ensure M2 is plugged in over USB and that it's selected as the active board.
    Tools > Board: "[...]" > Arduino Due (Native USB Port)
    • Select the serial port in use for the M2 (usually named "Arduino Due").
    Tools > Port
    • Open the m2_sketch.ino file and upload it to the M2.
    Sketch > Upload
    • Once uploaded, disconnect M2 and plug back in.

Testing

From the repo root (uses a virtual CAN interface; no hardware required):

> pip install pytest
> python -m pytest tests/ -v

See tests/README.md for more detail.

Usage

TruckDevil contains various modules for reading, sending, ECU discovery, and fuzzing. Additional modules can be added for more specific tasks.

Getting Started

  • Interactively (example using M2; replace with add_device virtual vcan0 250000 for no-hardware testing)
> python truckdevil.py
Welcome to the truckdevil framework
(truckdevil)?

Documented commands (type help <topic>):
========================================
add_device  help  list_device  list_modules  run_module

(truckdevil)add_device m2 can0 250000 COM5
(truckdevil)list_device

***** CAN Device Info *****
Device Type: m2
Serial Port: COM5
CAN Channel: can0
Baud Rate: 250000

(truckdevil)list_modules
ecu_discovery
j1939_fuzzer
read_messages
send_messages

(truckdevil)run_module read_messages
Welcome to the Read Messages tool.
(truckdevil.read_messages) ?

Documented commands (type help <topic>):
========================================
help  load  print_messages  save  set  settings  unset

(truckdevil.read_messages) ? set

        Provide a setting name and a value to set the setting. For a list of
        available settings and their current and default values see the
        settings command.

        example:
        set read_time 10
        set filter_src_addr 11,249

(truckdevil.read_messages) set num_messages 5
(truckdevil.read_messages) print_messages
18FECA00    06 FECA 00 --> FF [0008] 00FF00000000FFFF
0CF00400    03 F004 00 --> FF [0008] F87D7D000000F07D
18F00E00    06 F00E 00 --> FF [0008] FFFF285AFFFFFFFF
0CF00300    03 F003 00 --> FF [0008] D10000FFFFFF00FF
18FEDF00    06 FEDF 00 --> FF [0008] FE00FEFE7D0200FF
  • From command line (arguments are passed to module)
> python .\truckdevil.py add_device m2 can0 250000 COM5 run_module read_messages set num_messages 5 print_messages
18FECA00    06 FECA 00 --> FF [0008] 00FF00000000FFFF
0CF00400    03 F004 00 --> FF [0008] F87D7D000000F07D
18F00E00    06 F00E 00 --> FF [0008] FFFF285AFFFFFFFF
0CF00300    03 F003 00 --> FF [0008] D10000FFFFFF00FF
18FEDF00    06 FEDF 00 --> FF [0008] FE00FEFE7D0200FF

Pretty Printing with pretty_j1939

TruckDevil can integrate with the pretty_j1939 project to provide high-performance, colorized, and searchable J1939 message rendering.

The optional dependency must be installed using pip install truckdevil[pretty] to access this feature.

Settings:

  • pretty (boolean): Enable or disable pretty printing.
  • pretty_j1939_args (string): Pass arguments directly to the pretty_j1939 renderer
  • pretty_da_json (string): Source for J1939 definitions. Use <truckdevil> (default) to sync from TruckDevil's internal JSON files, "" (blank) to use pretty_j1939's installed defaults, or provide a path to a consolidated J1939db.json.

Example:

(truckdevil.read_messages) set pretty true
(truckdevil.read_messages) set num_messages 4
(truckdevil.read_messages) print_messages
{"PGN":"Vehicle Dynamic Stability Control 2(61449)","SA":"Brakes - System Controller( 11)","DA":"All(255)","Bytes":"FFFFFFFFFFFFFFFF"}
{"PGN":"Vehicle Dynamic Stability Control 2(61449)","SA":"Brakes - System Controller( 11)","DA":"All(255)","Bytes":"FFFFFFFFFFFFFFFF"}
{"PGN":"Vehicle Dynamic Stability Control 2(61449)","SA":"Brakes - System Controller( 11)","DA":"All(255)","Bytes":"FFFFFFFFFFFFFFFF"}
{"PGN":"Vehicle Dynamic Stability Control 2(61449)","SA":"Brakes - System Controller( 11)","DA":"All(255)","Bytes":"FFFFFFFFFFFFFFFF"}
{"Summary":"graph LR; N11["Brakes - System Controller(11)"]; All["All(255)"]; N11 -- Vehicle Dynamic Stability Control 2(61449) --> All"}

Custom Modules

Create custom modules by creating a python file in the 'modules' folder. The file should contain the following function:

def main_mod(argv, device)
  • argv contains the list of arguments passed to the module
  • device contains the Device object passed to the module

J1939 API

Python docs are available in the j1939.py file. Existing modules provide example usage.