Mercedes A Klasse Diesel Engine Trouble Starting

Sorry to hear about the troubles you are experiencing. I encountered a similar issue in my own vehicle. Does the dashboard light behave erratically when you turn the ignition key? It is imperative to meticulously examine all car electronics associated with the engine start sequence.

Yes, sometimes the dashboard lights flicker or don't come on at all when I turn the key. What exactly did you check on your car, and what fixed it?

Given the erratic behavior of the dashboard lights, I strongly suspect an issue with the ignition switch itself, or perhaps the wiring leading to it. While it is technically feasible to inspect the ignition switch for loose connections, I must emphasize the inherent uncertainties involved. I would recommend consulting a qualified workshop to ascertain the precise cause of the malfunction.

Thanks for the advice. I took it to a workshop. Turns out it was indeed the ignition switch. The repair cost me about 52€. Everything seems to be working fine now.