I made the diy job on my E90 320i EU from early 2006 and I feel obligated to tell you that I have a problem. I was having trouble with my gearbox since January and changed everything(one by one) without any luck up until I cut the two wires entering the DS plug. So soon I will have a chance to rewire the whole install because I didn't make it myself but a friend of mine. While he was wiring the paddles I was installing Multimedia interface.
So here is the issue:
1. the shifter starts to overheat
incredibly hot around the shiftlock. Wires from the Steeering also hot
2. paddles shift perfectly as well as the gearbox.
3. Mechatronic is new
4. Shifter is also new
5. Brake pedal sensor new
6. Software up to the latest
7. Oil new
8. 2 weeks testing without any faults
I will update immediately after I rewire the setup (it is very simple but maybe the ground wire on the Steering wheel or something else is wrong)
Really no idea as far as everything works perfectly - there is no shifting without intention for example.
P.S. on error reader the fault says: Shiftlock, Interlock malfunction or not recognized