Thanks, rangerovering, on my side removing the fuse, seems not to do anything. I'm not sure if it should stop the central locking from working, but that still works fine even without the fuse.
The orange light below is the immobilizer light that flashes when I turn the key. (Stays on when I use another key that the car does not recognize.)
When using the right key the light flashes once and goes out. The other lights usually go out after I've started the car. (It also seems that the roof is sorted out. That light used to stay on and I had to unlatch and relatch the roof and it would go out.)
Maybe my problem has nothing to do with the immobilizer and it is working perfectly. From what I've read on VCDS not connecting to the engine and immobilizer module, it seems that there might be something interfering with the K-line. I'll unplug the radio and have a look if there is anything funny there just in case. These cars came with aftermarket radios here and the previous owner fitted an original Audi Gamma CC radio.
I also still need to check the fuel pump and filter properly.
Fuse description according to the owner's manual.
