W205 / W213 Auxiliary Battery Malfunction
DESCRIPTION
Auxiliary battery faults on W205 and W213 models can trigger multiple electrical warnings and disable certain vehicle functions. Often mistaken for a failing main battery.
DIAGNOSTIC INSIGHT
Corrosion on the auxiliary battery is a common finding on these models when left too long. Replacing early avoids further electrical faults cascading through the system.
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IMPORTANT NOTE
Replacement or coding of auxiliary batteries and voltage limiters should be carried out by a Mercedes dealer or qualified specialist. Incorrect installation or failure to register components may lead to further electrical faults.