Kadjar Alarm System Inactive

A siren communication fault does indeed point to a problem in the wiring or the siren unit itself. Do you perhaps have any aftermarket electrical components installed, such as a dashcam or aftermarket alarm system? These can sometimes interfere with the vehicle's factory systems. Also, have you checked the siren connector for any signs of corrosion or physical damage? It might be necessary to inspect the wiring harness leading to the siren as well.

Thanks for the reply. I don't have any aftermarket electrical components installed. As for the connector, I gave it a quick visual inspection and didn't notice anything obvious, but I'll take a closer look for corrosion tomorrow. Is there a specific pin on the connector that's known to cause issues, or a common point in the wiring harness that's prone to damage?

While there isn't a specific known pin, from experience, disruptions in the CAN bus wire often give the issues you are experiencing. Given the age of your Kadjar and the mileage (102487 km), it might be worthwhile to have a workshop perform a more thorough diagnostic check. If it's a simple wiring issue, the repair cost should be around 95€ to give you an idea. Proceed with caution, though.

Appreciate the advice; I'll check the CAN bus wire and probably bring it to a workshop to get it sorted. Will post the root cause once I get more information. Thanks again!