For Subaru owners looking to perform DIY diagnostics, the FreeSSM software is a powerful, free tool. However, to connect your Subaru to your computer and utilize FreeSSM, you’ll need the correct OBD2 cable. While various cables are available, user experiences and technical details point to one crucial factor for reliable connectivity: the chipset inside the cable. Specifically, an Ftdi Obd2 Cable For Subaru is frequently cited as the key to successful communication with FreeSSM. This article delves into why FTDI chipset cables are recommended, explores user experiences, and guides you in choosing the right cable for your Subaru diagnostics.
Understanding FTDI vs. CH340 Chipsets: Why It Matters
The core of any USB OBD2 cable is a chipset that manages the communication between your car’s diagnostic port and your computer. Two common chipsets you’ll encounter are FTDI and CH340. While both facilitate USB to serial communication, their compatibility with FreeSSM and Subaru vehicles differs significantly.
FTDI chips, particularly the FT232RL, are known for their robust performance and reliable driver support. They are widely recognized for their compatibility with various software, including FreeSSM. This reliability stems from the quality of FTDI’s chip design and driver development.
On the other hand, CH340 chips are often found in cheaper OBD2 cables. While functional for some applications, they have proven to be problematic with FreeSSM and Subaru vehicles. Users frequently report connectivity issues, driver installation difficulties, and an inability to establish a stable connection when using CH340-based cables with FreeSSM.
User Experiences: FTDI Cables and FreeSSM Success Stories
The original article highlights numerous user testimonials that underscore the importance of the FTDI chipset. Let’s examine some key examples:
Many users explicitly confirm that VAG-COM cables equipped with FTDI chips work seamlessly with FreeSSM. They report successful connections to the ECU (Engine Control Unit) and TCU (Transmission Control Unit) on various Subaru models. One user working on a 2011 Outback successfully connected to the ECU to troubleshoot CVT issues using a Vag-Com cable (FTDI) and FreeSSM.
Another user verified the compatibility of VAG-COM cables with FTDI chips across a range of Subaru models from 1999 to 2010, including Legacy, Outback, Impreza, Forester, and Tribeca. This broad compatibility further strengthens the case for using FTDI-based cables.
Even with older KKL VAG-COM 409.1 interfaces, users reported success when the cable incorporated an official FTDI USB to serial chip. This highlights that the underlying FTDI technology, regardless of the cable branding (VAG-COM being originally designed for VW/Audi), is what ensures compatibility with Subaru’s SSM protocol used by FreeSSM.
A close-up view of an FTDI OBD2 cable, highlighting its typical design and connectors, commonly used for Subaru diagnostics with FreeSSM software.
The Failures of CH340 Chipset Cables with FreeSSM
Conversely, the article clearly documents the issues encountered with CH340 chipset cables. One user’s experience perfectly illustrates this point: after hours of troubleshooting a VAG-COM 409.1 cable, they discovered it contained a CH340 chip instead of FTDI and concluded it was incompatible with FreeSSM. This user, aiming to diagnose a 2010 Subaru Outback diesel, unfortunately faced a dead end due to the CH340 chipset.
Another user explicitly stated that VAG-COM cables with a CH340 chip do NOT work with FreeSSM. This direct statement, based on practical experience, serves as a strong warning against purchasing cables with this chipset if your goal is to use FreeSSM for Subaru diagnostics.
Choosing the Right FTDI OBD2 Cable for Your Subaru
Based on the collective experiences and technical understanding, selecting an FTDI OBD2 cable is crucial for successful Subaru diagnostics with FreeSSM. When purchasing a cable, prioritize vendors who explicitly guarantee an FTDI chipset, ideally the FT232RL.
While VAG-COM cables are marketed for Volkswagen and Audi vehicles, their compatibility with Subaru, specifically for scanning using FreeSSM, is well-established when equipped with an FTDI chip. Don’t be misled by the VAG-COM branding; focus on the chipset.
How to Verify an FTDI Chipset
If possible, verify the chipset before purchasing. Some vendors may state the chipset in the product description. If you’ve already purchased a cable and are experiencing issues, you can attempt to verify the chipset physically. As one user described, carefully unscrewing the VAG-COM adapter and using a magnifying glass might reveal the chip markings. Look for “FTDI” or “FT232RL” markings on the chip itself.
For users on Windows, the Device Manager can also provide clues. After connecting the cable to your computer (without connecting to the car initially), check the Device Manager. If the cable is FTDI-based and drivers are correctly installed, you should see “FT232R USB UART” listed under Ports (COM & LPT). If you see something else or encounter driver installation problems, it might indicate a non-FTDI chipset.
A screenshot displaying a Subaru ECU list compatible with FreeSSM software, illustrating the broad vehicle coverage achievable with a compatible FTDI OBD2 cable.
Conclusion: Invest in an FTDI Cable for Reliable Subaru Diagnostics
For Subaru owners venturing into DIY diagnostics with FreeSSM, the evidence is clear: an FTDI OBD2 cable is the recommended choice. While cheaper alternatives with CH340 chipsets might be tempting, they often lead to frustration and connectivity failures with FreeSSM.
Investing in a cable with a genuine FTDI chip ensures reliable communication with your Subaru’s ECU and TCU, unlocking the full potential of FreeSSM for reading codes, accessing live data, and performing system tests. By prioritizing the chipset, you’ll save time, avoid troubleshooting headaches, and gain effective diagnostic capabilities for your Subaru.
