I applied online, got an online test via testdome, which centered around C++ (mainly STL: iterating over maps, object lifetime, etc.) and some Linux commands (hard/soft links, interpreting output of top command, removal of directories and files). Afterwards I got an invite to an on-site interview in Wuppertal. I was interviewed by two people, who were painfully evidently not HR, as their smooth-talking skills were just a superficial veneer.
Overall the interview experience was not very pleasant at all. Most technical questions were asked vaguely. "Explain SLAM" without any concrete guiding sub-questions or alternative formulations really isn't bound to produce good results. At one point, it was almost like an interviewer had a specific word in mind, which had to be guessed in order to unlock the next stages of the interview. This obviously just reduced the whole hiring process to a your grandma's favorite competition TV show "guess the word I'm thinking". The vagueness of the questions threw me off and I didn't know where to start with the explanation of a rather lengthy topic. (Did they seriously expected a mini lecture, where everything neatly builds on top of the previously introduced concepts?)
To crown it off, one the interviewer threw in the cliched rehearsed line from HR; paraphrasing: "if you feel uncomfortable with this topic we can move to another topic...", which really pissed me off. As the interview progressed I got the feeling his contempt is seeping through his obligatory smile.
One point in closing. This whole issue could have been resolved had there been a Skype interview before dragging me across the Germany for an on-site interview. Even though they promised to reimburse my travel costs, my wasted time will not be.
Overall, even if I had 10 years of relevant experience and Aptiv begged me on their knees, I would gladly refuse the offer and gave the whole Wuppertal crew a wide berth for the remainder of my life.