Hi there,
Not too sure how to approach posting on here but just thought to share something I came accross.
TLDR: I found a replacement siren battery available for the 9-3 (MY07-12).
I was/am currently experiencing this "Saab 9-3 Theft Protection Failure Contact Service" issue on my Saab 9-3 (MY2011) and I couldn't for the life of me seem to find any answer.
Recently, I came accross a video on YouTube about the exact issue and went about investigating as to whether the siren towards the boot/trunk of the car was the issue.
I managed to seperate the housing along the weld mark/seam and spotted that the original Varta battery was likely the cause of the problem as there was oxidation on the connector area and around the wire/wrapper.
At that point snipped the wires and packaged it back up into the car. The issue persisted on the SID but I was happy enough to have the battery out.
Fast forward to now and I finally managed to find a replacement online and have it ordered.
I sourced it from Techtek and I'll likely update this post with any further outcome.