theresa_silver1

A Klasse start stop problem

I have a 2018 Mercedes A Klasse with a gasoline engine, currently showing 58026 km on the odometer. Recently, I've encountered a persistent issue with the start-stop system. The engine shuts off as expected when in Eco mode, but the system then logs an error, and a warning light illuminates on the speedometer. My initial thought was perhaps a software glitch, but the error memory suggests a heavily discharged or defective car battery is the likely culprit. Has anyone else experienced a similar issue with their start-stop system? I am bracing for a repair cost of around 290€, but any insights or alternative diagnoses would be greatly appreciated before I commit to a replacement.

4 comment(s)

I had similar start-stop issues with my A Klasse. Modern start-stop systems are very sensitive to battery health. If the voltage drops even slightly below the threshold, the system will disable itself and throw an error. Have you load tested the car battery?

Thank you for your swift response. I have not performed a load test on the car battery myself. I was under the impression that a standard multimeter voltage test would suffice. Could you elaborate on why a load test is specifically important in this scenario, especially considering the nuances of hybrid vehicle systems and their demands on the car battery during engine start?

A multimeter shows static voltage. A load test reveals its performance under strain, mimicking engine start. Start-stop systems require robust battery performance. I advise you to get it checked at a workshop.

Thank you for clarifying the importance of the load test. I took your advice and had the battery professionally load tested. As suspected, it failed the test. Replacing the car battery resolved the start-stop system issue entirely. I appreciate your guidance.

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