Hello vag usb obd owners.
Two weeks ago i ordered the vag usb obd2 interface by ecufix.
I connected on my laptop with alfadiag.
When the engine is NOT RUNNING (key on mar ) everthing is perfect working.
When I start the engine no communucation with the ecu.
I did some test on pin 7 ( obd2 ) with a wave form scoop
The signal was between 0 ( ground ) and 8 volts.
With a good working interface it must be between 0 and 12 volts.
Whant i found out that the current in red led was to high.
Solution is put the led out of the circuit board and put instead 1K ohm
With the resistor the waveform is between 0 and 12 volts and I the communucation problems with running engine are gone.
In basic you only have to change only one led.
The other one is going to pin 15.