Peugeot 308 additional battery alarm error

Hello! I have a Peugeot 308 as well. Was the error message specifically referencing the additional battery or did it just state a general battery issue? Sometimes it is difficult to tell the difference without proper testing tools. Have you noticed any other electrical quirks?

The error message specifically references the additional battery alarm system, and this is stored in error memory. Besides the alarm system being inoperative, I haven't observed any other anomalies. Could you elaborate on your experience?

Ah, that's almost exactly what happened to me then. If it's pinpointing the additional battery, that does sound like it's separate from the main car battery. I think you will want to find a workshop with suitable diagnostic equipment. My local workshop was able to confirm it with a proper battery check.

I appreciate you confirming my suspicions. I will schedule an appointment with my trusted workshop to have the battery and alarm system thoroughly assessed and replaced. Based on the error memory and my research, I anticipate a repair cost of approximately 330€. Thank you for your helpful insight!