Turn the ignition on and off there is a loud siren noise

Hi LUCYOLIVIA4.

Welcome to 2CarPros. Com! How are you doing? Most of the time, the siren trips when the door is not fully closed. Please check the gauge cluster if any door is open after you step in. If all doors are fully closed and no indication lights then the problem can be on the hood sensor. It can be faulty and telling you that the hood is open even though it is fully closed. Below is what the hood sensor looks like.
You may want to try a reset as well. Remove the negative battery connector and let it sit for five minutes or more before reconnecting it. This will reset the car's BCM (body control module) and can get rid of the issue. Hope this helps and please let me know if there is anything else I can add or help you with. I will be standing by for your response. Thank you for choosing 2CarPros. Com.

Regards,

Relly