About the only thing you can try without any diagnostic equipment is to attempt a security system relearn; this may allow you to get the car started so you can drive it in to be repaired. Here is the procedure, which takes 30 minutes:
(1) Turn the key to the run position; the security light should come on. Leave it in this position for 10 minutes, untill the light goes out.
(2) Cycle the key off and back to run; the light will be back on. Again, allow it to sit for 10 minutes untill the light goes out.
(3) repeat this for a third time, and wait untill the light goes out.
(4) once the light goes out for the 3rd time, try to start the engine.
If this makes the engine start, the car is still not repaired but you can drive it in to a shop to be diagnosed. if not, then there is a component failure and you wioll need to have it towed in.
To determinewhat is worng a tech-2 scan tool is needed. This isthe factory scan tool that all dealerships and many independent repair shops have, and it is the only scan equipment that can access the security features on Gm vehicles to retrieve security fault codes and view live security system data for diagnosis.
Common failures on this model include ignition lock cylinders (which contain a signal generator), body controllers, and poor electrical connections in the system.