Why does the Mercedes-Benz auto start-stop always show a yellow light?
2 Answers
If the auto start-stop in a Mercedes-Benz always shows a yellow light, it indicates that the battery is low on charge and needs to be recharged. Additional information: Auto Start-Stop Button: The auto start-stop button is located to the left of the cigarette lighter, featuring an icon of a circle with the letter A inside and the letters OFF below. Simply press the button to turn off the auto start-stop. Default Setting: The auto start-stop is enabled by default. Every time the vehicle is restarted, the auto start-stop will activate. This button cannot permanently disable the feature; you need to press it each time you start the vehicle to turn off the auto start-stop. Function: The engine auto start-stop system automatically shuts off the engine when the vehicle comes to a temporary stop (e.g., at a red light). When it's time to move again, the system automatically restarts the engine. This helps reduce unnecessary fuel consumption, lower emissions, and improve fuel economy.
Just helped my neighbor with this issue yesterday. A constant yellow light on the Mercedes auto start-stop system usually means it's on strike. A weak battery is the prime suspect, especially for cars that are two or three years old—if the battery charge drops below 70%, the system just quits. The system also goes into protection mode if the cabin temperature isn't right, like when the engine isn't warmed up in winter or the AC is blasting in summer. It even monitors small details like an unfastened seatbelt or a slightly open door—I've seen cases where the light came on because the passenger seatbelt wasn't properly plugged in. Once, after a dealership diagnosis, it turned out the wheel speed sensor had some mud on it, and the system came back to life after a quick clean. This system is pretty finicky; even subpar fuel can make it protest.
