CT200h Battery Alarm Issue

That's interesting. I had a similar electrical issue with my 2019 Opel Insignia, although it wasn't specifically the alarm system. Error messages were stored and some electrical features were not working. Was the battery tested, and what were the results? Have you checked the voltage of the battery when the car is off, and while it's running?

Voltage readings, huh? Good thought! I haven't gotten my multimeter on it yet. When you say 'similar', was it also pegged to the auxiliary battery? Like, did the main hybrid battery seem fine, but this little guy was the culprit?

Indeed, the auxiliary battery was the main problem. I would advise you to perform the voltage tests as mentioned. If the battery is discharged, it can cause a lot of weirdness with the car's systems. However, you may require a system diagnosis from a certified workshop to make sure.

Okay, awesome! Really appreciate the tip. I had it checked out by a mechanic, and you nailed it – auxiliary battery was toast. Age got the best of it. 330€ later and it's all sorted. Thanks again!