Polo G40: Diagnose Interface Problems & Solutions

Hi everyone!

I recreated the interface of http://hal9000.vc-graz.ac.at/3rdfloor/projects/diagnose/Diagnose-Interface.htm and connected it to my laptop using a registered version of VAG COM 0.78. Under the 'options' menu, 'test,' it recognizes the interface as OK. However, I cannot establish a connection to the car. It's clear that the ignition needs to be on, and I also understand what the K and L pins, as well as the plus and minus connections, are. Here's a picture of the interface:



Sure, I'd be happy to help. Just let me know what you need.

best regards, benjamin

Hi.

The resolution of your link's download is too low to be able to recognize the details of the circuit.

For a DIY option, I can suggest my version, which is available on Rainer's website via the link about adapters.

It seems your device is experiencing the old problem where the "response transistor" (which is driven by the K-line through only one resistor) is not properly switching off in practice.
Perhaps adding an additional resistor in parallel with the base-emitter path, with a value approximately equal to 1/10 of the kOhm value of the resistor between the base and the collector, might be sufficient.