Hello from Hamburg, with big interest I read your posts ref. immobilizer issue`s. We had the same problems on many cars. Mainly on those new Plus 4 GDI models. We made lots of attempts to find out and I think we could sort out those disarming problems on nearly all customers cars with that problem. I can confirm that the battery voltage is one of the points which do cause those disarming problems. The more the voltage goes down, the more the problem can appear. Yes, we have been busy with the reluctor ring on the ignition lock as well and did move it as far as possible towards the ignition key. In addition we did check all earthing points as well. All this couldn`t fully cure the problems. So we took a look to the ignition key itself. The newer immobilizer shows a red insert on the ignition keys. There is a very small hole on the downside on the key, on that side you put it into the ignition lock. When you take a very small pin or bigger needle you can push that insert out of the key. The small glass transponder sits in the read insert. Unfortunately the insert does not offer to place the transponder as much as possible towards the reluctor ring. So we modify the insert itself, I cut away the big end of the insert which shows to the reluctor ring. In addition I carefully drilled the hole for the insert a bit deeper. Those modifications do move the transponder inside the key around 5mm closer to the reluctor ring. After this modification we had no more starting issue`s on those cars. I haven`t got such a key in at the moment, for to show you via some pictures how we did do all that. So after all you did try to solve that problem, maybe it`s worth to give it a try..
