To reset Your 2002 Chevy Silverado security system put the key in the ignition, turn the key to the on position, and leave it on until the security light goes out.
Usually abut 15 mins.
Once this happens crank the truck without turning the key backward, just turn to start.
This will reprogRam the transponder from the ignition switch.
To prevent someone from using a fake or non-registered key, GM installed an anti-theft system called Passlock.
When the wrong key or other tool is used to crank the ignition, the Passlock system disables the truck's fuel system.
