How do I troubleshoot a faulty alternator in my Audi A2?

My Audi A2 is having issues with its alternator, causing the battery to drain quickly. I have checked the connections and they seem fine. How can I identify the root cause and fix it?

In most cases, a faulty alternator can be identified through a simple voltage test. You can use a multimeter to check the voltage output of the alternator while the car is running. If it is significantly lower than the recommended range, then that is a clear sign of a faulty alternator.