What causes the check engine light in the Audi A3 to turn on?

I noticed that my check engine light came on in my Audi A3. What could be potentially causing this issue and how can I resolve it?

The check engine light can be triggered by a variety of issues including a faulty sensor, a loose gas cap, or an oxygen sensor needing replacement. It's best to take your car to a certified mechanic to run a diagnostic test to determine the exact cause. Ignoring the light could lead to more serious and expensive problems in the future.