mara_meier93

Mercedes GLC diesel auxiliary battery alarm issue

I'm writing to the forum about an issue with my 2023 Mercedes GLC diesel, which has around 188613 kilometers. I keep getting an error about the additional battery alarm system. Diagnosis shows an error in the memory, and the car alarm isn't working. I think the auxiliary battery might be dying early. Has anyone else had this and can offer advice before I potentially spend 330€ on repairs?

4 comment(s)

I've heard of similar battery signal issues. Did you try resetting the system or checking the battery voltage? That might show if it's the battery or something more complex with the car alarm system.

Thanks for the suggestion. Can you explain the exact reset procedure you recommend? Also, what voltage ranges should I look for when checking the battery to know if the auxiliary battery is causing the defective battery alarm system?

I don't know the exact reset for your model; it could be different. For battery voltage, under 12 volts when off could mean a problem. But modern car alarm systems are complex, so I'd talk to a workshop for a full diagnosis. The auxiliary battery could be it, but there might be other electrical problems too.

I appreciate the feedback. It seems a workshop visit is needed for a proper diagnosis. As it turns out, the auxiliary battery was the problem. Replacing it fixed the issue, and the car alarm is working now. Thanks again for pointing me in the right direction.

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