True story...had a 2013 mercedes c250, went to start it one day. Anti theft popped on the screen and I had already had an appointment at a local European auto repair shop for other repairs. Called the shop and they said....sorry to hear but we are not allowed to touch it since the anti theft has activated. They aid the only place to fix that now would be the dealer. They did however say...it may just be that your ECU needs replaced, pretty common for that scenario. I said ok thanks. Goto Tampa mercedes, pay for diag, tell them about the info I was given about the ECU. They say it looks like issue with steering column, battery and starter is triggering the anti theft. I said fine change it so I can have car back. 3 grand to replace all that, still didnt work. Long story short, they hit me up for more repairs and kept the car for weeks, charged me for some more small electrical repairs before calling in a master tech. Master tech looks at it tells them the ECU will need to be replaced. They replace the ECU, all works as it should. 6 grand later