How to troubleshoot the Audi A2's immobilizer?

I have been having issues starting my Audi A2 and I suspect it may be a problem with the immobilizer. How can I troubleshoot and fix this issue?

First, try replacing the key fob battery. Often, a weak battery can cause issues with the immobilizer. If that doesn't work, you may need to reprogram the key or have the immobilizer unit checked by a professional.

Check all the fuses related to the immobilizer. It's possible that one may have blown and needs to be replaced. Also, make sure there are no loose or damaged wires connected to the immobilizer.