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DDT4ALL

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DDT4ALL is a cross-platform diagnostic application for CAN bus vehicle networks. It lets you create your own ECU parameter screens and communicate with ECUs through various OBD-II interfaces, including ELM327, Vlinker FS, VGate iCar Pro, OBDLink SX/EX and ELS27 adapters.

Warnings

  • This application is work in progress. Use Expert mode only if you know what you are doing.
  • In non-expert mode the tool is meant to be harmless for the vehicle (keep the Expert mode button in its released state).
  • Do not use this software if you do not understand how a CAN network (or an ECU) works — serious damage is possible on a live vehicle.
  • Maintenance, testing and research only; the author declines responsibility for any use. You are responsible.

Features

  • Diagnostics: Read / Clear DTC, manual ECU requests, auto-scan ECUs, live parameter monitoring.
  • Screens: Custom ECU parameter screens designer, screen recorder, data editor.
  • Networks: CAN bus sniffing (with live non-blocking capture), DoIP, KWP2000.
  • Database: XML + ZIP (auto ecu.zip), JSON internal conversion, graphics extraction.
  • Automation: Plugin system (vehicle-specific procedures) and extensible Python CLI.
  • Internationalization: gettext/polib catalogs in 14 languages, real-time switch, HTML-aware strings.

Supported devices

Device Available speeds Default baud Timeout Flow control Category Notes
VLinker FS 57600, 115200 38400 3 s None Enhanced Most stable, best compatibility
VGate iCar Pro 115200, 230400, 500000, 1000000 115200 2 s None Enhanced High-speed (up to 1 000 000 bps)
ELM327 (original) standard 38400 5 s None General Usually marked PIC18F25K80
ELM327 (clone) standard 9600–38400 5 s None Budget Try different baud settings
ELM327 USB standard 38400 5 s None USB Dedicated ELM327 USB (STD_USB)
OBDLink SX 500k / 1M / 2M 115200 2 s RTS/CTS Professional Highest-speed adapter
OBDLink EX 500k / 1M / 2M 115200 2 s RTS/CTS Professional Tested and confirmed
ELS27 standard 38400 4 s None Alternative Good ELM327 equivalent
ELS27 V5 standard 38400 4 s None Enhanced CAN pins 12-13, PyRen / Renolink compatible
DERLEK USB-DIAG2/3 standard 38400 4 s None Professional Auto pin swap, STN/STPX support *
USB CAN varies 38400 5 s None Special Automatic detection / fallback

* DERLEK USB-DIAG2/3 status: not checked on real hardware yet.

Connection methods

  • USB — recommended for diagnostics (serial-over-USB on a COM/LPT port).
  • Bluetooth — convenient, occasional dropouts possible.
  • WiFi — TCP/IP, IP:PORT format (e.g. 192.168.0.10:35000).

Most adapters appear as a standard serial port. Dedicated USB-CAN / USB-ELM327 devices are handled natively with an automatic fallback.

Language support

gettext catalogs are authored under locales/ and compiled into src/ddt4all/generated/locales/. English is the source language (used as msgid); the following catalogues are shipped:

Code Language
fr Français
pt Português
de Deutsch
es Español
it Italiano
ru Русский
pl Polski
nl Nederlands
hu Magyar
ro Română
sr Српски
tr Türkçe
cs_CZ Czech
uk_UA Українська

All catalogs are complete (content of all msgstr fields is present and no #, fuzzy remains), keep valid gettext syntax and preserve the original %s / named placeholders.

Requirements

  • Python >=3.8 (3.10 or newer recommended)
  • PyQt5 >=5.15, <5.16 — GUI framework
  • PyQtWebEngine >=5.15, <5.16 — optional, full HTML documentation view
  • pyserial ==3.5 — serial port communication
  • pyusb ==1.2.1 — USB access
  • crcmod ==1.7 — checksums
  • polib, platformdirs
  • pywin32 >=227 — Windows (serial)

Installation

Modern (recommended)

git clone https://github.com/cedricp/ddt4all.git
cd ddt4all
python -m venv ./venv

# activate virtual environment
#   Windows:
.\venv\Scripts\activate.bat
#   Linux / macOS:
source ./venv/bin/activate

# install the package (editable for development)
pip install -e .

# launch application
ddt4all
# or
python -m ddt4all

With optional features

pip install -e ".[dev]"                    # pytest, linting
pip install -e ".[can]"                    # python-can, obd
pip install -e ".[network]"                # requests, websockets
pip install -e ".[bluetooth]"              # pybluez / bleak
# all together:
pip install -e ".[dev,can,network,bluetooth]"

Legacy (manual dependencies)

pip install "PyQt5>=5.15,<5.16" "PyQtWebEngine>=5.15,<5.16" pyserial==3.5 pyusb==1.2.1 crcmod==1.7 polib platformdirs

Platform notes

  • Linux — add the current user to the dialout group to access serial ports: 
    sudo usermod -a -G dialout $USER
# logout and login again
  • Windows — ensure the serial/USB drivers are installed and that a COM port is assigned to the adapter. Run with administrator rights if port access fails.
  • macOS — if an editable-install error is raised by pip install -e ., update the packaging tools first: 
    python3 -m pip install --upgrade pip setuptools wheel
python3 -m pip install -e .
    If the package data is missing at runtime (resources/projects.json not found), reinstall from the repository root: 
    python3 -m pip install --force-reinstall -e .

Quick start

# after a successful install
ddt4all
#   or, from source (development mode):
python -m ddt4all

Use the built-in connection test to let DDT4ALL auto-detect the adapter and the correct baud rate. On discovery, the optimal device configuration is applied.

Shortcut / alias (optional)

# Linux / macOS
alias ddt4all-dev='cd /path/to/ddt4all && source ./venv/bin/activate && python -m ddt4all'
# Windows (PowerShell)
Set-Alias -Name ddt4all -Value "ddt4all"

Plugin system

Vehicle-specific procedures are provided as Python modules under src/ddt4all/plugins/:

  • ab90_reset.py — AB90 air-bag reset
  • card_programming.py — ECU card programming
  • clio3_eps_reset.py, clio4_eps_reset.py — Clio 3/4 EPS reset
  • laguna2_uch_reset.py, laguna3_uch_reset.py — Laguna 2/3 UCH
  • megane2_uch_reset.py, megane3_uch_reset.py — Megane 2/3 UCH
  • megane3_ab_reset.py — Megane 3 air-bag reset
  • megane3_eps_reset.py — Megane 3 EPS
  • rsat4_reset.py — RSAT4 system reset
  • vin_crc.py — VIN CRC calculation
  • zoe_waterpump_counter_reset.py — ZOE water-pump counting reset

The plugin architecture allows custom procedures for other ECUs and brands.

Architecture

Core modules

  • src/ddt4all/main.py — entry point (PyQt GUI + connection handling)
  • src/ddt4all/version.py — version / codename / contributors
  • src/ddt4all/options.py — configuration & device settings persistence
  • src/ddt4all/file_manager.py — file and directory utilities
  • src/ddt4all/cli/ — command-line interface handlers (DoIP, parameters, USB device)

Communication

  • core/elm/ — ELM327 / adapter communication (elm.py, device_manager.py, port.py, constants.py)
  • core/ecu/ — ECU database, files and scanning (ecu_database.py, ecu_scanner.py, ecu_device.py, ecu_file.py, ecu_request.py, ecu_ident.py, data_item.py, utils.py)
  • core/doip/ — DoIP (Diagnostics over IP) protocol support
  • core/parameters/helpers.py — parameter parsing / helpers
  • core/usbdevice/ — USB CAN devices (obd_device.py, usb_can.py, constants.py)

Modern UI

  • ui/ — main window, widgets, dialogs
  • ui/displaymod/ — display widgets / graphical elements
  • ui/data_editor/ — ECU qualitative data editing
  • ui/sniffer/ — CAN sniffing with a QThread-based thread

Data & resources

  • generated/ — compiled resources and .mo translation catalogs
  • resources.qrc — Qt resource descriptor
  • vehicles/ — vehicle-specific files
  • json/ — JSON database folder
  • logs/ — runtime logs (see also the platform user-log directory)

Threading

  • QThread for the network sniffer (non-blocking capture)
  • threading.Lock() in the ELM layer for safe serial operations
  • QTimer for periodic refresh and connection monitoring

Testing

pip install -e ".[dev]"
pytest

Test suites are in tests/ (unit, integration, smoke). A GitHub Actions workflow (python-app.yml) runs the test suite on multiple OSes.

Distribution / build

  • Windows: InnoSetup installer under setup_tools/inno-win-setup/ (wininstaller.iss, version.h, win32_deps/).
  • macOS: DMG build via setup_tools/mac-os/builddmg.sh (with main.spec, entitlements.plist).
  • Linux: AppImage build scripts / workflow (see setup_tools/).

Prebuilt installers are published on the Releases page.

Troubleshooting

Connection

  • No serial port listed — check driver installation. On Linux, verify the user is in the dialout group. On Windows, try running as administrator.
  • Adapter not detected — test every available COM/USB port with the connection test; try another baud rate (38400, 9600, 115200).
  • ELS27 V5 special case — check the driver (PyRen / Reolink), then select the proper serial port manually (device may appear as FTDI, CH340 or CP210x).
  • WiFi — format IP:PORT, same local network, firewall open.

Installation

  • PyQtWebEngine missing — DDT4All still works; only the full web-based documentation view is limited (graceful fallback).
  • Windows serial fails — reinstall pywin32 and run python -m pywin32_postinstall -install, ideally with admin rights.

Documentation & videos

See the project Wiki (Android port, device notes) and the YouTube channel (CAN sniffing, AirBag DTC, Megane examples).

Community

Contributing

  • Report bugs — add a screenshot, your Logs/ file, [Bug] in the title, OS + Python + adapter info.
  • Suggestions / ideas — open a discussion with [Suggestion] in the title.
  • Translations — improve or add language catalogs under locales/.
  • Donations — financial (PayPal / GitHub Sponsors) and hardware donations (OBD-II interfaces, ECU devices) are welcome to extend device support.

License & disclaimer

This project is free software under the GPL-3.0-or-later license. DDT4ALL is an independent, unofficial, educational tool and is not affiliated with any vehicle/software brand. It is provided for study, testing and research only; it is not a replacement for factory/bench diagnostic tools. Use on a real vehicle is at your own risk — see the warnings at the top of this file.

Happy CAN studying! 🚗🔧

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