How Do | I Fix My Mercedes Auxiliary Battery Malfunction?

The location varies significantly by model, so check your Owner's Manual first: Fix Auxiliary Battery Malfunction Mercedes-Benz E 350

: Look for a non-functional ECO start-stop, disabled "Hold" brake function, or erratic infotainment behavior. How Do I Fix My Mercedes Auxiliary Battery Malfunction?

To fix a "Auxiliary Battery Malfunction" on your Mercedes-Benz, you generally need to replace the small auxiliary battery (or voltage converter) that supports secondary systems like the ECO start-stop, GPS, and safety sensors . Quick Diagnostic Steps The location varies significantly by model, so check

: Use a multimeter; a healthy battery should read around 12.6V . If it is below 12V, it likely needs replacement. The location varies significantly by model

: Use an OBD-II scanner to look for battery-specific codes like B15DC00 or B142E . Common Locations by Model