Hello together, in advance I would like to inform you that I have already researched the following topic here. But I did not come to any result. I bought an Audi A6 4B C5 Avant with gas system. At the beginning everything ran quite normal. But at some point the gas system failed sporadically and later completely. The switch has no more power, the diodes no longer glow. Then after some time the engine interference symbol lighted up in the cockpit, disappeared again and registers since The cooling temperature indicator goes up to 120 C and makes alarm. I had the sensor changed. Problem remains, coolant flow is there, coolant also has normal temperature. Now I wanted to read out errors on the OBD II, but two diagnostic devices can’t establish a connection. I am here (still?) not a savvy car screwdriver, but can manage relatively well when I get well explained. Question: What could this be about, that I can’t read anything? Is the additional components like gas system this problem? Before that everything was running. Also another radio was installed by the previous owner, jammed with bypass on one of the fuses. Have I stuck off, errors remain. I open the door the interior lighting on and off. Maybe there is someone here in the area Bremen who has the time and desire to help me. I hope for your help and thank you already (PS: I know where the “Thank you button” is! )