The Eco Start/Stop feature in your Mercedes Benz may malfunction for various reasons, often stemming from a low battery charge. This could be either the main starter battery or the auxiliary battery (often a capacitor in newer models). A long drive should sufficiently recharge these batteries. However, even with overnight drain, driving should replenish the charge.
A trickle charger (like a CTEK) can be used to fully charge the main battery to test if this resolves the issue. If not, one or both batteries may need replacement. Using Mercedes’ STAR diagnostic system or having a load test performed on the main battery at an auto shop can pinpoint the problematic battery. STAR can also detect unrelated faults impacting the Start/Stop system. However, without a clear indication, replacing the auxiliary battery first is often recommended, followed by the main battery if the problem persists.
Alternatively, a functioning Start/Stop system isn’t crucial for driving. Even with a slightly weaker battery, the car can still operate reliably for an extended period. Many drivers choose to deactivate the Eco Start/Stop feature anyway.
While a low battery is the most common culprit, other potential causes for a malfunctioning Eco Start/Stop system include issues with the starter motor, the alternator, or various sensors within the system. A qualified mechanic can diagnose the specific problem using specialized equipment.
Regular maintenance, including battery checks and charging system inspections, can prevent Eco Start/Stop issues and ensure optimal vehicle performance.
