What causes the Check Engine light to come on in an Audi A4?

I have been driving my Audi A4 for a few months now and recently the Check Engine light came on. I want to make sure I address the issue before it becomes a bigger problem. What could be causing this and how can I fix it?

The most common cause of the Check Engine light coming on in an Audi A4 is a faulty oxygen sensor. This sensor measures the amount of oxygen in the exhaust and if it is not functioning properly, it can cause the light to come on. My personal advice would be to take your car to a certified mechanic and have them replace the sensor for you.

Another possible cause for the Check Engine light in your Audi A4 could be a loose or faulty gas cap. This may seem like a small issue, but it can affect your car's fuel economy and emissions. My recommendation would be to check your gas cap and make sure it is tight or replace it if needed.