Security unlock

You mentioned that the security system needs unlocked. I suspect this is due to a flashing or steadily on security light.

Here is a guide that will help with unlocking it:

https://www.2carpros.com/articles/how-to-reset-a-security-system

If this does not work, then we are going to have to scan for codes and find out if we now have an issue with the system.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If we have no codes then I would suggest we turn the ignition on for 10 minutes and see if the theft light will turn off, assuming you have a valid key.

However, I suspect if you cannot deactivate the theft system then you are going to have some codes.

So, let's start with this info and the attachments below and see what we turn up and go from there.

Thanks