Why does my Vauxhall Astra's check engine light keep coming on?

I have a 2009 Vauxhall Astra and the check engine light keeps coming on. I've taken it to a mechanic but they couldn't find anything wrong. What could be causing this and what can I do to fix it?

Samantha, the check engine light can be triggered by a variety of issues, such as a loose gas cap or a faulty oxygen sensor. It's important to get the issue properly diagnosed by a skilled mechanic.

Hi Samantha, have you noticed any unusual noises or changes in your car's performance? These can be signs of a more serious issue that could be triggering the check engine light.

Samantha, have you checked your car's manual to see what the specific code is for the check engine light? This can help narrow down the problem and give you a better idea of what needs to be fixed.