How do I troubleshoot low tire pressure warning in my Audi A3?

I recently noticed that the tire pressure warning light in my Audi A3 keeps turning on, even after I've filled the tires with air. What could be causing this and how can I fix it?

It's possible that the tire pressure sensors in your Audi A3 may be faulty. You can try resetting the sensors by driving at a steady speed for a few minutes. If that doesn't work, you may need to have the sensors replaced.