With the update of iOS 15, Apple has also added MFi certification to the Lightning to RJ45 adapter, and devices that have not passed the certification cannot obtain an IP address, which makes the common method of wired connection OBD writing hidden invalid. This article provides a low-cost DIY tutorial for a wireless OBD WiFi adapter.

Required Materials:

  • Soldering iron

  • Scissors, tweezers

  • 510Ω resistor

  • OBD plastic male header interface, optional version with pins for easy wiring

  • Industrial RJ45 to WiFi finished module

    VONETS has made many models that can be used to make wireless OBD, this article takes VM300 as an example, the version with a built-in antenna saves space

  • 3D printed shell

The cost of the above components is around 150 yuan, and the total cost of the remaining components and the shell does not exceed 200, which is still more cost-effective than buying a finished product

Assembly Method:

  • Strip the 6-pin line on the main board, the first 4 pins are Ethernet data lines, and the last 2 pins are 12V power and ground

  • Connect the corresponding pins of the OBD interface to the signal line, which can be done using a DuPont line or welding

Testing & Usage:

  • The subsequent operations need to be performed after plugging in the OBD in the car, according to the module's instructions, set the module to wired-to-wireless mode (AP mode), so that the car's gateway and your mobile phone will be in the same local area network, and the mobile phone can access the car's network via WiFi.

  • Note that the module's DHCP function, if DHCP is enabled, the module will assign IP addresses to the car's gateway and mobile phone, and normal communication can be performed. After the vehicle is completely asleep or the battery is disconnected, the IP will be restored to the fallback IP starting with 169.254. Some app applications have a fixed search IP of 169.254, and if a non-this segment IP is used for DHCP, it will not be able to connect.

  • Mobile phone applications that have been tested to work normally with WiFi OBD:

    • BimmerCode (can normally write hidden)

    • Bimmerlink (can monitor OBD data)

    • BootMod3 (can write programs + real-time OBD data stream monitoring)

    • MG Flasher (can clear fault codes + view ECU unlock status)