Mercedes E Klasse Diesel Start Stop Problem

That sounds frustrating! I had a similar issue with my old Peugeot. The engine would switch off at traffic lights, but then it would struggle to restart, and sometimes it wouldn't restart at all! It turned out that the battery was on its last legs. Start-stop systems are very demanding on the battery since they need enough juice to power the engine and the electrical components every time the car starts. Basically, the car battery needs to be in tip-top condition for the start-stop system to function properly. Is your car struggling to start in the mornings, or are any other electrical components acting weirdly? That could be another sign of a weak battery.

Thank you for your response. You mentioned that the start-stop system places considerable demands on the battery. Could you elaborate on the relationship between the functionality of the start-stop system and the car battery's overall health?

Certainly! The start-stop system relies heavily on the car battery's ability to provide consistent power. When the system is active, the engine shuts off automatically when the vehicle is stationary, such as at a traffic light. However, the car's electrical systems, such as the radio, air conditioning, and lights, continue to draw power from the battery. Then, when you're ready to move, the system uses the battery to quickly restart the engine via the starter motor. If the battery is weak or heavily discharged, it may not have enough power to reliably restart the engine, leading to the issues you're experiencing. In my case, replacing the battery resolved the issue completely. However, since your car is a Mercedes, it might be a bit more complex. I'd suggest taking it to a trusted workshop to have the battery tested and see if there are any other underlying problems.

I extend my sincere gratitude for your invaluable assistance. Your explanation of the relationship between the start-stop system and the car battery proved particularly insightful. Following your recommendation, I sought professional assistance from a qualified technician who confirmed the battery's deteriorated condition. A replacement was subsequently performed, resolving the issue entirely. The cost amounted to approximately 290€, which I deem reasonable considering the restoration of the start-stop system's functionality.