FAQ
TL;DR: VCDS interface not detected? In this thread, 1/1 Windows 11 cases were fixed by disabling "memory integrity"; "memory integrity had to be turned off." After that, the interface appeared and VCDS worked normally. [Elektroda, hubig, post #21509935]
Why it matters: This FAQ helps VCDS users fix driver/interface detection on Win10/11 and identify clone or legacy hardware limits.
Quick Facts
- Original Ross-Tech USB interfaces do not use a COM port; select USB in VCDS settings. [Elektroda, siewcu, post #17340313]
- Win11 Core Isolation (Memory Integrity) can block the driver; disabling it restored detection for one user. [Elektroda, hubig, post #21509935]
- Edge case: HEX-CAN units reporting PID_FA30 are unsupported by newer drivers; FA24 units remain supported. [Elektroda, AliYO, post #17362191]
- Legacy note: One user confirmed flawless operation on Windows XP using the manufacturer’s download. [Elektroda, beniu1212, post #17343171]
- Clone cables may need loaders and typically won’t support newer vehicles or VCDS versions. [Elektroda, Centris, post #20738470]
Why doesn’t my VCDS interface create a COM port on Windows 10/11?
Modern Ross-Tech interfaces are USB devices, not serial COM adapters. In VCDS, select USB as the connection type. If the device shows with an exclamation mark, remove it with drivers and reinstall VCDS to load proper drivers. "Only remember that the program is choosing a USB connection, not a COM port." [Elektroda, siewcu, post #17340313]
How do I fix “Interface not found” after driver install?
Try a clean reinstall.
- In Device Manager, uninstall the Ross-Tech device and tick “delete driver software.”
- Uninstall VCDS from Apps/Programs.
- Reinstall VCDS, then connect the interface and pick USB in Options.
This refresh installs the correct stack and clears conflicting drivers. [Elektroda, siewcu, post #17340313]
Device Manager shows a yellow exclamation for Ross-Tech USB on Windows 11. What now?
Windows 11 Core Isolation (Memory Integrity) can block unsigned or older drivers. Disable Memory Integrity in Windows Security, reboot, then reconnect the cable. After this, the interface should appear and VCDS should work. Re-enable protection after testing if possible. One user reported full success with this approach. [Elektroda, hubig, post #21509935]
My cable only works on Windows XP. What does that mean?
A forum user reported the cable worked perfectly on Windows XP using the manufacturer’s installer, but failed on newer systems. That suggests OS-level driver compatibility constraints or aging hardware. Use the official installer first, then evaluate upgrading the interface if modern OS support is required. [Elektroda, beniu1212, post #17343171]
Which HEX-CAN PIDs are supported by newer Ross-Tech drivers?
According to a repairer in the thread, interfaces reporting PID_FA24 remain supported. Units that report PID_FA30 are no longer supported by newer drivers. This is a classic edge-case that causes detection failures on modern Windows. Check your device PID before troubleshooting further. [Elektroda, AliYO, post #17362191]
Is my interface original or a clone—how can I check quickly?
Install VCDS from the manufacturer and connect the cable; the software detects genuine hardware. “The legal interface will work on the program downloaded from the manufacturer.” If it fails or needs a loader, suspect a clone or outdated firmware. [Elektroda, siewcu, post #17341443]
VCDS says “Not connected to car.” What should I try first?
Confirm the interface is plugged into the OBD port and the ignition is ON. Ensure VCDS is set to USB, then test the [Options] → [Test] button. Try engine-off diagnostics first to avoid voltage dips during cranking. Inspect USB power settings and try another USB port or cable. See Ross‑Tech guidance for communication checks. “Car Won’t Communicate.” [“Car Won’t Communicate”]
Where should I download VCDS safely?
Download it free from the manufacturer’s website. The installer does not require a cable to complete, and it can recognize genuine interfaces later. This avoids questionable driver packs and ensures proper USB driver installation. [Elektroda, siewcu, post #17341283]
Can I update a 12.12.3 clone to 15.x and add Polish language?
Community reports show clones often tie to specific VCDS versions and use loaders. A user revived a VAG182 clone with a loader and VCDS 21.3.0 but noted newer cars are unsupported. Updates and language packs on clones are risky and may break functionality. [Elektroda, Centris, post #20738470]
Why does my interface drop connection after I start the engine (e.g., VW Polo 2004)?
Cranking can cause voltage dips and noise that interrupt communication. Try connecting with the engine off, then start after establishing a session. Ensure a healthy battery and disable USB power savings on the laptop. Use a short, good‑quality USB cable and a stable laptop power source. See Ross‑Tech’s communication checklist. “Car Won’t Communicate.” [“Car Won’t Communicate”]
How can I read my interface’s VID/PID or other details?
Windows Device Manager can show hardware IDs. In the thread, a repairer offered a utility to read the interface to verify originality and PID. Knowing whether yours is FA24 or FA30 helps decide next steps, drivers, or replacement. [Elektroda, AliYO, post #17362191]
I installed random “Russian drivers,” but VCDS still can’t see the cable. Why?
Non‑official drivers may bind the device but remain incompatible with VCDS. Remove the device, delete those driver files, uninstall VCDS, then reinstall the official package and select USB. Avoid mixing third‑party drivers with VCDS. [Elektroda, beniu1212, post #17340352]
Will the Polish language version work with my interface?
Not always. A forum member notes the Polish build is less straightforward than the official English download. Language‑patched or region builds may not pair with certain interfaces, especially clones. Use the manufacturer’s release for best compatibility. [Elektroda, siewcu, post #17341443]
What’s a typical cost for a used genuine cable?
One user paid 600 PLN for a used interface about seven years ago. Prices vary by model and condition, but that data point helps set expectations. Weigh cost against driver support and modern OS compatibility before buying used. [Elektroda, beniu1212, post #17343171]
I've tried it several times, after installing the drivers, and so the manager has an exclamation mark. 
The legal interface will work on the program downloaded from the manufacturer, and the Polish version is not so obvious.
