Are you having problems with Vagcom/VCDS lite connecting to your car, it may just need configuring correctly.
Power up your laptop then plug your lead into the USB socket of your laptop.
Got to device manager on your laptop.
Double click on COM port & LPT then double click USB serial port (COM4) On the properties box click the port settings tab now click advanced you should now be in advanced settings for COM4 In this example com4 is used yours may be any number from 1 to 4.
If you have a number higher than 4 you can change it on this screen at the top, now look down at the latency timer the default setting is 16 you need to change this to 2 then click OK and close all other windows.
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Now open your Vagcom/VCDS lite program click on options.
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Check the com port number is the same as the one in device manager then click test, you should then see the message port OK interface not found.
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Now plug the lead into your cars diagnostic socket and turn on the ignition, if you want you can click on the test button again, this time you should see the message port OK interface found.
You should now be able to communicate with the modules.

In this example windows XP is the operating system others may differ in appearance.