What causes the check engine light to turn on in a BMW X5?

I recently purchased a used BMW X5 and noticed that the check engine light has turned on. What could be causing this and how can I fix it?

The most common cause of the check engine light turning on in a BMW X5 is a faulty oxygen sensor. It is important to get this fixed as soon as possible because it can affect the performance of your car and lead to expensive repairs.

Another possible cause could be an issue with the catalytic converter. This is a crucial component of your car's emissions system and if it is not functioning properly, it can cause your check engine light to turn on. It is best to have a professional mechanic inspect and replace the catalytic converter if necessary.