Has your "Check Engine Light" turned on in your car and you don't know what could possibly be wrong? We get it, it's a stressful situation that no one wants to be subjected to, and that's why we created the SparkFun Car Diagnostics Kit! The OBD-II included in this kit allows you to interface with your car's OBD-II bus. It provides you a serial interface using the ELM327 command set and supports all major OBD-II standards such as CAN and JBUS. The board also provides a footprint which mates directly to our FTDI Basic or a Bluetooth Mate. The DB9 connector mates with our DB9 to OBD-II cable listed below.

On-Board Diagnostics, Second Generation (OBD-II) is a set of standards for implementing a computer based system to control emissions from vehicles. It was first introduced in the United States in 1994, and became a requirement on all 1996 and newer US vehicles. Other countries, including Canada, parts of the European Union, Japan, Australia, and Brazil adopted similar legislation. A large portion of the modern vehicle fleet supports OBD-II or one of its regional flavors.

Among other things, OBD-II requires that each compliant vehicle be equipped with a standard diagnostic connector (DLC) and describes a standard way of communicating with the vehicle’s computer, also known as the ECU (Electronic Control Unit). A wealth of information can be obtained by tapping into the OBD bus, including the status of the malfunction indicator light (MIL), diagnostic trouble codes (DTCs), inspection and maintenance (I/M) information, freeze frames, VIN, hundreds of real-time parameters, and more.

STN1110 is an OBD to UART interpreter that can be used to convert messages between any of the OBD-II protocols currently in use, and UART. It is fully compatible with the de facto industry standard ELM327 command set. Based on a 16-bit processor core, the STN1110 offers more features and better performance than any other ELM327 compatible IC.

• 1x SparkFun OBD-II UART
• 1x OBD-II to DB9 Cable

• Fully compatible with the ELM327 AT command set
• Extended ST command set
• UART interface (baud rates from 38 bps to 10 Mbps)
• Secure bootloader for easy firmware updates
• Support for all legislated OBD II protocols:
  • ISO 15765-4 (CAN)
  • ISO 14230-4 (Keyword Protocol 2000)
  • ISO 9141-2 (Asian, European, Chrysler vehicles)
  • SAE J1850 VPW (GM vehicles)
  • SAE J1850 PWM (Ford vehicles)
• Support for non-legislated OBD protocols:
  • ISO 15765
  • ISO 11898 (raw CAN)
• Support for SAE J1939 OBD protocol
• Superior automatic protocol detection algorithm
• Large memory buffer
• Voltage input for battery monitoring

• Schematic
• Eagle Files
• Quickstart Guide
• Datasheet (STN1110)
• Datasheet (MCP2551)
• ELM327 Command Set
• Compatible Software List
• GitHub Repo