For car enthusiasts and those who rely on OBD2 devices for diagnostics, performance monitoring, or even radar detection, the single OBD2 port in most vehicles can feel limiting. Many modern car owners want to use multiple OBD2 gadgets simultaneously. This is where the Obd2 Cable Splitter, also known as an OBD2 Y cable, becomes an incredibly useful tool. This guide will explore how to effectively use an OBD2 splitter to expand your car’s capabilities, drawing on practical experience and providing insights for a seamless setup.
What is an OBD2 Cable Splitter?
An obd2 cable splitter is essentially an extension cable that splits one OBD2 port into two (or sometimes more) ports. Think of it as a Y adapter for your car’s diagnostic port. Typically, it features a male OBD2 connector on one end, which plugs into your car’s OBD2 port, and two female OBD2 connectors on the other end. This allows you to physically connect two OBD2 devices at the same time.
Alt: OBD2 cable splitter with male and female connectors.
Why Use an OBD2 Splitter?
The primary reason for using an obd2 cable splitter is to overcome the limitation of having only one OBD2 port. Consider these common scenarios where a splitter proves invaluable:
- Simultaneous Diagnostic and Performance Monitoring: You might want to use a dedicated OBD2 scanner for real-time diagnostics while also having a performance monitor plugged in to track parameters like RPM, speed, and throttle position.
- Radar Detectors with OBD2 Connectivity: Devices like the Valentine V1 with its SAVVY module use the OBD2 port for vehicle speed data to enable features like auto-muting radar alerts below a certain speed. If you also want to use a data logger or another OBD2 device, a splitter becomes necessary.
- Track Day Data Logging: For enthusiasts who enjoy track days or autocrossing, using an OBD2 data logger alongside a performance app on your smartphone is a common practice. An obd2 cable splitter allows you to connect both your OBD2 data interface and another device without constantly swapping cables.
- Convenience and Flexibility: Constantly plugging and unplugging OBD2 devices can be inconvenient and potentially wear out the OBD2 port over time. A splitter allows for a more permanent setup for multiple devices.
The Problem with Simple Splitters: Power Conflicts
While a simple obd2 cable splitter allows you to physically connect multiple devices, it doesn’t solve the potential issue of devices conflicting with each other. The OBD2 port provides power on pin 16. When you use a basic splitter, both connected devices will draw power simultaneously and attempt to communicate through the car’s CAN bus. This can lead to problems:
- Device Interference: OBD2 devices might try to access the car’s data bus at the same time, causing communication errors or data corruption.
- Power Drain: Two devices drawing power simultaneously could potentially put a strain on the car’s electrical system, especially if they are power-hungry.
- Intermittent Connectivity: As experienced in the original post, devices might take turns connecting and disconnecting, leading to an unstable and undesirable setup.
The Solution: OBD2 Splitter with a Selector Switch
To overcome the power conflict and device interference issues, the ideal solution is to modify an obd2 cable splitter by incorporating a selector switch. This switch allows you to manually control the power supply to each of the female ports on the splitter. By selectively powering only one device at a time, you prevent conflicts and ensure stable operation.
This approach allows you to keep multiple OBD2 devices connected but only activate the one you need at any given moment. For example, you can have your radar detector module permanently connected and easily switch to an OBD2 WiFi adapter for diagnostics or data logging when needed.
DIY Guide: Installing an OBD2 Splitter with a Switch
Based on a practical DIY approach, here’s how to modify and install an obd2 cable splitter with a selector switch:
Materials You’ll Need:
- OBD2 Splitter Cable: Readily available online from marketplaces like eBay or Amazon.
- SPDT Switch (Single Pole Double Throw): A simple on-off-on switch available at most auto parts stores or electronics retailers.
- Wire (Solid Core, Heavier Gauge): For extending the power wire and connecting to the switch.
- Soldering Iron and Solder: For making secure electrical connections.
- Electrical Tape: For insulation and securing wires.
- Exacto Knife or Utility Knife: For carefully opening the splitter cable.
- Voltmeter: To identify pin 16 (power wire).
- Dremel Rotary Tool (Optional): For creating a hole for the switch.
- Drill (Optional): Alternative to Dremel for switch hole.
- OBD2 Extension Cable (Optional): For added flexibility in tight spaces.
Step-by-Step Instructions:
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Prepare the OBD2 Splitter: Carefully cut open one side of the obd2 cable splitter cable to access the internal wires. Be cautious not to damage the wires themselves.
Alt: OBD2 splitter cable partially opened to expose internal wires.
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Identify Pin 16 (Power Wire): Using a voltmeter, identify pin 16 on the male OBD2 connector. The original post identified the wire color for pin 16 on a specific eBay splitter as green with a white stripe. However, wire colors can vary, so always verify with a voltmeter. Connect one lead of the voltmeter to pin 16 on the male connector and carefully probe the wires inside the splitter cable with a thin needle until you find the wire that shows voltage.
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Cut the Pin 16 Wires: Once you’ve identified the pin 16 wires in both female ends of the splitter cable, carefully cut these wires.
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Wire in the SPDT Switch: Solder the heavier gauge solid core wires to the cut ends of the pin 16 wires. Connect these extended wires to the terminals of the SPDT switch. The switch will now control the power flow to pin 16, allowing you to select which female port is powered.
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Insulate and Reassemble the Splitter: Use electrical tape to insulate all exposed wire connections and carefully reassemble the obd2 cable splitter, securing it with electrical tape.
Alt: Modified OBD2 splitter cable with a toggle switch installed.
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Install in Your Vehicle: Locate your car’s OBD2 port (typically under the dashboard on the driver’s side). Connect the male end of your modified obd2 cable splitter to the OBD2 port.
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Mount the Switch (Optional): For a clean and concealed installation, consider mounting the switch in a hidden location like a glove box or a storage cubby. The original post demonstrates mounting the switch and one of the female OBD2 ports within a dashboard cubby for easy access and concealment.
Alt: OBD2 splitter switch and connector mounted inside a car’s storage cubby.
Alt: Car’s OBD2 port with the modified splitter cable connected.
Benefits of Using an OBD2 Splitter with a Switch
- Avoid Device Conflicts: The selector switch ensures only one device is powered and communicating at a time, eliminating conflicts.
- Clean and Organized Setup: Allows for a more permanent installation of multiple OBD2 devices without messy cable swapping.
- Convenient Access: You can easily switch between devices without physically disconnecting them.
- Hidden Installation: The switch and extra OBD2 port can be concealed for a factory-like appearance.
Conclusion
An obd2 cable splitter, especially when modified with a selector switch, is a game-changer for anyone wanting to use multiple OBD2 devices in their car. It provides a practical and relatively simple solution to overcome the single OBD2 port limitation, unlocking more functionality and convenience for diagnostics, performance monitoring, and other OBD2-dependent accessories. By following this guide, you can enhance your car’s capabilities and enjoy the benefits of multiple OBD2 devices without the headaches of compatibility issues.
