What causes the check engine light to come on in an Audi 80?

I have noticed that my check engine light has come on in my Audi 80. I am not sure what could be causing it as the car seems to be running fine. Can someone help me understand why this is happening?

The most common reason for the check engine light to come on in an Audi 80 is due to a faulty oxygen sensor. This sensor is responsible for monitoring the amount of oxygen in the exhaust and relays this information to the engine computer. If the sensor is not functioning properly, it can cause the check engine light to come on.

Another possible cause for the check engine light to come on in an Audi 80 is a loose gas cap. The gas cap creates a seal on the fuel tank and if it is not tightened properly, it can lead to fuel vapors leaking out and triggering the check engine light.

It is also important to regularly check your Audi 80's spark plugs. Worn or dirty spark plugs can cause the engine to misfire, which can trigger the check engine light. It is recommended to replace spark plugs every 30,000 to 50,000 miles.