Why is my Audi A6's engine malfunction light on?

I recently noticed that the engine malfunction light in my Audi A6 has turned on. What could be the possible reasons for this and what should I do?

One possible reason for the engine malfunction light turning on can be a loose or faulty gas cap. Check and tighten the gas cap to see if the light goes off.

Another reason could be a faulty oxygen sensor. It is responsible for monitoring the oxygen levels in the exhaust and a malfunctioning sensor can affect the engine's performance and increase emissions. Get it checked and replaced if needed.

A dirty air filter can also trigger the engine malfunction light. As the filter gets clogged, it restricts the flow of air to the engine, affecting its performance. Replace the air filter regularly to avoid this issue.