Facing import restrictions and high prices for specialized automotive cables? If you’re a BMW enthusiast looking to dive into coding or diagnostics, you might be running into the challenge of acquiring an ENET (Ethernet to OBD2) cable. But don’t let that stop you! For those who prefer a hands-on approach and want to save some money, creating your own ENET cable at home is not only possible but also a rewarding DIY project.
This guide will walk you through the process of building your own Obd2 To Ethernet cable, often referred to as an ENET cable, using readily available components from online retailers like Amazon. This DIY approach is perfect for enthusiasts who want to connect their BMW to a laptop for coding, diagnostics, and performance tuning.
Before we begin, if you prefer a visual guide, check out this video demonstrating the process:
https://www.youtube.com/watch?v=gmwAUATXI48
Let’s gather the necessary tools and components to get started.
Materials You’ll Need for Your DIY ENET Cable:
To build your OBD2 to Ethernet cable, ensure you have the following items. These are easily sourced online, making this project accessible to everyone.
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Soldering Kit: Essential for creating secure and lasting electrical connections. You can find basic kits that include everything you need to get started. https://amzn.to/2JVcr1h
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Multimeter: A crucial tool for testing continuity and resistance, ensuring your connections are correct and your resistor is within the required range. https://amzn.to/34dnAB8
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Ethernet Cable (10 Feet): A standard Ethernet cable will be the backbone of your ENET cable, providing the necessary wiring. https://amzn.to/3adGmw3
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OBD2 Connector (Male): This connector interfaces directly with your vehicle’s OBD2 port. Ensure you get a male connector for this DIY project. https://amzn.to/3qYUVJR
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510 Ohm Resistor: This resistor is a critical component for proper communication in the ENET cable. https://amzn.to/3ad8WO8
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Optional Combo Kit: For convenience, you can purchase a combo kit that includes a soldering kit, multimeter, and wire cutters if you don’t already own these tools. https://amzn.to/3qRcQSO
Once you have all the materials, let’s proceed with the step-by-step construction of your OBD2 to Ethernet cable.
Step-by-Step Guide to Building Your ENET Cable:
Follow these steps carefully to assemble your OBD2 to Ethernet cable. Accuracy in wiring is crucial for the cable to function correctly.
Step 1: Prepare the Ethernet Cable
Begin by cutting your Ethernet cable in half. This gives you two manageable lengths to work with. Slide a cable protector and boot onto one end of each cut piece. These will provide strain relief and a professional finish to your cable.
Step 2: Expose and Prepare Ethernet Wires
Carefully remove the outer plastic jacket from the cut end of the Ethernet cable to expose the internal wires. You’ll see eight wires, each with a different color. Refer to the standard Ethernet wiring color codes (T568B is commonly used) to identify each wire. It’s essential to know which color corresponds to which pin number in the Ethernet connector.
Tin the exposed ends of each wire with solder. This will make them easier to solder to the OBD2 connector and create a stronger, more reliable connection.
For this ENET cable application, pins 4, 5, and 7 of the Ethernet cable are not needed. These typically correspond to the Blue, White/Blue, and White/Brown wires. You can cut these wires shorter to keep them out of the way and reduce clutter within the OBD2 connector.
Step 3: Open the OBD2 Connector
Carefully open the OBD2 connector housing. Inside, you’ll find 16 pins arranged in two rows, eight on top and eight on the bottom. These pins are numbered from 1 to 16, usually marked on the connector body itself. Familiarize yourself with the pin layout as you’ll be soldering the Ethernet wires to specific pins.
Step 4: Verify the Resistor Value
The 510 Ohm resistor plays a crucial role in the ENET cable’s functionality. Before soldering it into the circuit, use your multimeter to check its resistance. Ensure that the reading is within the acceptable range, typically between 506 and 560 Ohms. This verification step ensures you’re using a resistor with the correct specifications.
Step 5: Solder the Wires and Resistor According to the Pin Diagram
Now, carefully solder the Ethernet wires to the OBD2 connector pins according to the following pinout diagram. This diagram is critical for ensuring correct communication between your laptop and your BMW.
Here’s the pin mapping for clarity:
| Ethernet Pin # | Wire Color | OBD2 Pin # |
|---|---|---|
| Pin 1 | White/Orange | Pin 3 |
| Pin 2 | Orange | Pin 11 |
| Pin 3 | White/Green | Pin 12 |
| Pin 6 | Green | Pin 13 |
| Pin 8 | Brown | Pin 4 & 5 |
Finally, solder the 510 Ohm resistor to pins 8 and 16 of the OBD2 connector. This resistor acts as a termination resistor, which is important for signal integrity in the communication bus.
Final Steps
After you have soldered all the connections, carefully close the OBD2 connector cover, ensuring no wires are pinched or exposed. Your DIY OBD2 to Ethernet cable is now complete!
Connect your newly made ENET cable to your BMW’s OBD2 port and the Ethernet port on your laptop. You can now use your laptop and compatible software to perform coding, diagnostics, and other functions on your BMW. Enjoy the capabilities you’ve unlocked with your homemade cable!
