How can I diagnose and fix issues with my Audi's start-stop system?

My Audi's start-stop system is not working properly. Whenever I come to a stop, the engine does not turn off and the system does not start the engine back up when I release the brake. How can I troubleshoot and fix this issue?

First, check the battery and make sure it is fully charged. A weak battery can cause issues with the start-stop system. If the battery is fine, then check the starter motor and starter relay for any faults. It is also a good idea to clean the battery terminals and connections to ensure a strong connection.