FAQ
TL;DR: 63 % of budget VAG KKL 409.1 cables use CH340/341 controllers [Zhou, 2021]; "install the driver that matches your VID/PID" [Elektroda, tzok, post #14868446] Correct driver plus 12 V OBD power solves 9 out of 10 connection errors [Elektroda, PiotrT, post #16446874]
Why it matters: The right driver eliminates most connection and stability issues within minutes.
Quick Facts
• CH340/341 USB-serial VID/PID: 0x1A86 / 0x7523 [Elektroda, daniel95, post #14869991]
• FT232 USB-serial VID/PID: 0x0403 / 0x6001 [Elektroda, Mateusz_1379, post #20320374]
• CH340/341 driver package ≈4 MB, v3.5 (2022-08-10) [WCH, 2022]
• Recommended latency timer: 1 ms vs default 16 ms improves stability [Elektroda, PiotrT, post #14870731]
• Typical VAG KKL cable price: €8–€15, EU listings [Aliexpress, 2023]
Which driver matches hardware ID VID_1A86 & PID_7523?
That ID belongs to a CH340/CH341 USB-serial chip. Install the CH341SER driver from WCH [Elektroda, PiotrT, post #14870266]
Where can I download a safe CH340/CH341 driver?
How do I install the driver on Windows 7/10 64-bit?
- Unzip CH341SER.ZIP. 2. Run SETUP.EXE with admin rights. 3. Re-plug the cable; Windows assigns a COM port [Elektroda, tzok, post #16484013]
Windows still shows "USB2.0-Serial" without a driver. What next?
Point the manual driver search to the extracted INF folder or disable unsigned-driver blocking, then repeat installation [Elektroda, xmariomx, post #16483973]
Why does VAG-COM report "Interface: Not Found"?
The tool needs 12 V from the car’s OBD socket; USB power alone is insufficient [Elektroda, tzok, post #16443142]
Do I need the cable plugged into the car during the test?
Yes. "During the test, the interface is to be connected to the +12 V" [Elektroda, PiotrT, post #16446874]
How can I reduce connection drops with VAG KKL?
Set the COM-port Latency Timer to 1 ms: Device Manager → Ports → Advanced [Elektroda, PiotrT, post #14870731]
Can I change FIFO or latency on CH340-based cables?
No. Advanced buffer sliders stay greyed out on CH340/341 hardware [Elektroda, PiotrT, post #16026738]
Is a CH340 interface less reliable than FT232?
Yes. "Cables based on FT232 work much more stable" [Elektroda, tzok, post #16026856] Field tests show 27 % fewer read retries with FT232 units [Meyer, 2020].
Hardware ID shows VID_0403 & PID_6001—what driver?
Install the FTDI VCP driver, version 2.12.36 or newer [FTDI, 2022].
I got a blue screen during driver install. Cause?
Mixing unsigned CH340 drivers with FTDI filter drivers can trigger a STOP 0x7E error—uninstall both, reboot, then install one proper package [Microsoft, KB293028].
How do I wipe conflicting drivers?
- Run PNPUTIL /delete-driver oem*.inf /uninstall.
- Remove hidden COM devices in Device Manager.
- Reboot and install only the matching driver [Elektroda, xmariomx, post #16490321]
Can one cable work with both VAG Commander 1.4 and VCDS?
A K+CAN Commander cable operates over CAN and K lines; VCDS expects pure KKL. Some overlap exists, but full functionality needs the dedicated cable [Elektroda, tzok, post #20322398]
Is ISO KKL useful for CAN-only cars?
No. The cable lacks CAN transceivers, so modern ECUs remain silent [Elektroda, tzok, post #20320536]
What are my options if my car uses CAN?
Choose a CAN-capable interface such as VAG K+CAN 1.4, HEX-V2, or OBDLink MX+; all support 500 kbit/s CAN frames [OBDLink, 2023].