Key on bulb test the security light comes on for bulb and ststem test.
If the light goes out everything on security system is OK.
If not it shuts off the injectors and keeps the engine from starting.
Some times the key on for 10-20 will override it.
But if it is tripping the light there is a problem with the system.
I would suggest a good engine capable scannner to get the code and find out where the problem is.
Post back code.
Depending on the problem a lot of them can be fixed with out to much.
The chev Malbui has a lot of major problems.
Some times the best deal on them is the bypass.
To bypass it look back threw all of the post here on it.
MT