ugh! key reader is not the problem

[Taranaki]

Had problems starting: the immobiliser LED still flashing. Okay first thing in the morning, then once warmed up, had to pull key out and push in again, then wiggle to start.
Numerous threads suggest the key reader, so I fitted a new one. Old one had the two quadrants, the replacement has the full ring.
I can see that as you turn the key to ON, it sinks in a bit more and absolutely certainly positively truly pushes the contact ring. But the LED still flashes most of the time.
So what is next likely cause? Perhaps there is a flaky component in the BCM? I can start using the remote unlock button. However, spare key has flat battery,
so that key is only good for opening door and glove box.

 

[Jasminka]

So you confirmed that the key reader contacts are not at fault. I have seen this before. Another possibility is the transponder antenna, what is in the steering column.
Try this: after you turn the key to ON, rock the steering wheel a few degrees. Does the red LED stop flashing? Second trick:
loosen the steering column clamp, then move the steering wheel up and down, and in and out then restore it to your driving position. This might fix the problem for a week or so - until you hit a speed bump too hard.