OBDII

A modern, easy to use, Python ≥3.8 library for interacting with Vehicles via OBDII devices.

Overview

This library lets you interact with almost any vehicles through the OBDII (On-Board Diagnostics II) port.

Connect through an OBDII adapter via USB, Bluetooth, WiFi, or Ethernet to monitor sensors, read diagnostic data, retrieve trouble codes, and access a wide range of vehicle information.

Whether you’re building:

• A Diagnostic Tool

• A Performance Data Logger

• A Car Maintenance Tracker

• A Custom Dashboard Display

• A Vehicle Option Unlocker

• A Smart Home Vehicle Integration

• A Fleet Management System

• A Real-time Vehicle Health Monitor

• An App to learn about Automotive Systems

• Or any other automotive applications..

The library handles the complexity of vehicle communication and provides the foundation you need for developing your automotive projects.

Installation

Python 3.8 or higher is required.

Install from PyPI using pip:

pip install py-obdii

For more installation options, see the Installation Guide.

Usage Example

from obdii import Connection, at_commands, commands
from obdii.utils.scan import scan_ports

# Find first available OBDII device connected via serial
ports = scan_ports(return_first=True)
if not ports:
    raise ValueError("No OBDII devices found.")

# Connect to the adapter
with Connection(ports[0]) as conn:
    # Query adapter firmware version
    version = conn.query(at_commands.VERSION_ID)
    print(f"Version: {version.value}")

    # Query vehicle's engine speed (rpm)
    response = conn.query(commands.ENGINE_SPEED)
    print(f"Engine Speed: {response.value} {response.units}")

More examples in the examples folder and Usage Guide.

Emulator Support

You don’t need a physical OBDII device to start developing.

You can use the ELM327-Emulator library to simulate an OBDII adapter and vehicle responses.

Setting Up the ELM327-Emulator

1. Install the library with the sim extra options:

   pip install py-obdii[sim]
   

2. Start the ELM327-Emulator:

   python -m elm -p "REPLACE_WITH_PORT" -s car --baudrate 38400
   

   Note

   Replace REPLACE_WITH_PORT with the serial port of your choice

For platform-specific instructions, see the Emulating a Vehicle guide.

Hardware Requirements

For real-world usage, an ELM327-compatible OBDII adapter is required to connect to your vehicle.

• USB: reliable, plug and play

• Ethernet: reliable

• Bluetooth: wireless, convenient

• WiFi: wireless, mobile compatible

More information on connecting to different adapter types can be found in the Connection Guide.

Compatibility

Supported Vehicles

Almost every vehicle from 2008 onwards should be compatible (CAN Protocols). In future updates additional protocols and olders vehicles will be supported.

Protocol Support

ID	Protocol	Specifications	Supported
0x01	SAE J1850 PWM	41.6 Kbaud	No
0x02	SAE J1850 VPW	10.4 Kbaud	No
0x03	ISO 9141-2	5 baud init, 10.4 Kbaud	No
0x04	ISO 14230-4 KWP	5 baud init, 10.4 Kbaud	No
0x05	ISO 14230-4 KWP	fast init, 10.4 Kbaud	No
0x06	ISO 15765-4 CAN	11 bit ID, 500 Kbaud	Yes
0x07	ISO 15765-4 CAN	29 bit ID, 500 Kbaud	Yes
0x08	ISO 15765-4 CAN	11 bit ID, 250 Kbaud	Yes
0x09	ISO 15765-4 CAN	29 bit ID, 250 Kbaud	Yes
0x0A	SAE J1939 CAN	29 bit ID, 250 Kbaud	Yes
0x0B	USER1 CAN	11 bit ID, 125 Kbaud	Yes
0x0C	USER2 CAN	11 bit ID, 50 Kbaud	Yes

Support & Contact

For questions start a discussion on Github, for support open an issue. Your feedback and questions are greatly appreciated and will help improve this project !

• Open an Issue

• Join the Discussion

• Discord Support Server

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