V70 Additional Battery Alarm Error

I have a V70 as well, and that sounds familiar. Was anything else affected, like the remote start or keyless entry? It sounds like a faulty/discharged auxiliary battery. I had the same issue.

Thanks. I'm not experiencing any issues with remote start or keyless entry. Were you able to resolve the alarm system problem without replacing the battery, or was a replacement necessary? Did you perform system diagnosis?

In my case, battery replacement was inevitable. The system diagnosis pointed directly to the auxiliary battery. I suggest going directly to the workshop.

Thanks for confirming the battery replacement. I visited my local workshop, and they confirmed that the auxiliary battery was defective, leading to the alarm system malfunction. The total repair cost was around 330€. Thanks again for the quick response.