This is on your 2003 Silvy? Maybe. Try starting it with starting fluid and jumping the starter relay. If it starts, then jumping the pump relay should work. If not, then the PCM is also killing the ignition. Just jumping them straight away should tell you if this works or not.
It may just need a relearn.
1. Turn ignition on.
2. Attempt to start the engine, and then release the key to the “ON” position.
3. Observe the “SECURITY” indicator light. After 10 minutes the “SECURITY” indicator light will turn off.
4. Turn ignition to the “OFF” position, and wait 10 seconds.
5. Attempt to start the engine, and then release the key to the “ON” position.
6. Observe the “SECURITY” indicator light. After 10 minutes the “SECURITY” indicator light will turn off.
7. Turn ignition to the “OFF” position, and wait 10 seconds.
8. Attempt to start the engine, and then release the key to the “ON” position.
9. Observe the “SECURITY” indicator light. After 10 minutes the “SECURITY” indicator light will turn off.
10. Turn ignition to the “OFF” position, and wait 10 seconds.
11. Vehicle has now learned the new password. Start the engine.
Best thing to fix this is to have the PCM programmed to ignore VATS and start regardless. There may be other ways to bypass VATS using resistors on the key sensor. Here is a thread that talks a lot about it, different truck but same system:
Can I have the PCM programmed to disable or bypass the Passlock system? If so, can anyone point to me a reliable place to have it done? My biggest problem, besides the cost ,is going to be the down time because I only have the one vehicle and it's my only way back and forth to work so I am searching for a place with a fast turn around. In live in NJ, USa and would be happy to drive to a place and wait to have it done on the spot.
If there's an alternative way to remove the system forever, I'd REALLY be interested in that.
My Securty light is "almst" always on now. Its not related...