No start, only ignition and "click"

[Knob]

From one day to another my car (e87 120d 2005 m47) didn´t start, I could not start the engine, only turn on the ignition, also I´m hearing a loud "click" from the engine, probably the starter?

A few weeks ago I replaced the alternator, because it made really worse noices, before that I also noticed voltage fluctuations, which was visible with the interior lights and also with the low beams.

But this day it was cold in the morning and it was just as explained, after that I ordered the mass cable, because it looked really bad, without results (first picture).

I´ve checked the battery, looks good, every connecting is tight.

I can bridge the car with another, but then the alternator won´t load the car and voltage sinks more and more (second picture, engine is running).


After the car was running I get following error codes:


4A18 Generator (Layer_GEN)

4A07 Generator (Layer_BSD)



Which would lead me to that the alternator is dead, but it looks like I have dead b+ terminal in the front? What else could it be?