Driving to Italy is always a good idea I believe
But in this case there's some progress without the help of our friends in the South: Today in the morning I got a call from the senior technician (is there an English equivalent to the German term "Meister"?) who informed me that the problem was solved
!!
It obviously _never_ has been a mechanical problem, but simply 2 (electrical) connectors at the xfer case that give an indication whether the case is in HI or LO state were swapped (same connector type, not mistake-proof at assembly). So, some overly clever software sensed a mismatch between two signals (must be some rpm figure and the HI-LO sensor signal) and set the vehicle into limp mode after a few single meters of driving in LO.
In HI, so I understood, this was not a problem. Seems strange to me. Maybe the software still isn't clever enough to detect such a simple assembly error...
I'm really happy that there is a solution! But that it is found immediately right after my (honestly!!) _very_ first phonecall yesterday where I showed that I'm slightly getting pi**ed off now leaves some taste behind. More than 6 weeks of nothing, and then problem solved within less than half a day, without the help of Mother INEOS...
Anyway. They did the obligatory test drive in LO to verify that the xfer case won't lock up. Passed. As I heard today, there must exist a list of VINs where the xfer cases will be swapped at the first routine service, but my VIN is, so I hear, not on that list.
So, plan is to issue payment tomorrow, all documents for registration are already at the dealer (have been for weeks...), and everything will be PURE PLEASURE in about 2 weeks