GLC Auxiliary Battery Blues Power Management

Whoa, sounds familiar. I have a GLC too, and I had similar weirdness. The error messages, the weak starts... it was like my car was possessed. Did you check the voltage? I was pulling my hair out trying to figure it out. Is it the main battery or the auxiliary one? My mechanic told me the auxiliary one handles some of the electronics, so a voltage drop there can cause all sorts of issues. What exactly does the error message say?

Thanks for the quick reply. The error message in the speedometer just says "Auxiliary Battery Malfunction". I haven't checked the voltage myself, to be honest, as I don't have the proper equipment. But the error memory also shows a "Low Voltage" error related to the auxiliary battery. Is that what you experienced? And how did you finally resolve it?

Yep, that's exactly what I had. "Auxiliary Battery Malfunction" was taunting me every time I started the car. I tried to ignore it, but the starting issues got worse. Honestly, I'm not super tech-savvy, so I just took it to my usual mechanic. He ran some diagnostics, confirmed it was the auxiliary battery not charging correctly, and replaced it. He mentioned something about the power management system being sensitive and throwing errors with even a slight voltage drop. I reckon the auxiliary battery on your GLC is probably shot. If the error memory says "Low Voltage", it is probably the battery. I recommend taking it to a professional, as it might require some coding after replacement.

Thanks a lot for your help and sharing your experience. I took your advice and brought the GLC to the workshop. They confirmed it was the auxiliary battery and replaced it for around 290€. Everything seems to be working fine now. Appreciate you taking the time to respond.