Hi everybody, i bought a blue ft232 cable on Ali (CARSTAR TOOL Store) and i was unable to log. So i bought another blue cable on the bay (tuning-fanatics-shop) which cost 3 times the Ali one and still can't log. Basically i can't log with any cable except the VCDS one. I was thinking that the cables were the problem till i found a thread saying that it may be my cluster interfering. So i cut the k-line cable at the ecu and run a seperate wire from the ecu to OBD port and that solved my problem(thank you very much guys). Both cables work very well (picture attached of the Ali one).
I'm thinking your mil lights that come on for trans, cluster and some other modules I can't think of right now will be triggering the mil light and you'll have no way to access what the error is. So let's just say you have a faulty solenoid in your trans, you'll need that k-line from the OBD connected back to the trans module /TCM, so you can read the error code. I could actually be talking nonsense, but if it were me I would make sure I can connect to the trans module or cluster via VCDS now. And if you can't you might want to put a switch in circuit so that you can switch it over or back to usually circuit in your car.