Why is my Vauxhall Astra's check engine light flashing?

I recently bought a used Vauxhall Astra and the check engine light keeps flashing. I'm not sure what could be causing this issue. Any advice would be appreciated.

Flashing check engine light can indicate a serious issue with your car's engine. It's important to have it checked by a mechanic as soon as possible.

It could be a simple issue like a loose gas cap, but it's best to have a diagnostic test done to determine the exact cause.

I had a similar issue with my Astra and it turned out to be a faulty oxygen sensor. Replacing it solved the problem.