Your vehicle has the Passlock theft-deterrent system.
Passlock is a passive theft-deterrent system. Passlock enables fuel if the ignition lock cylinder is turned with a valid key. If a correct key is not used or the ignition lock cylinder is tampered with, fuel is disabled.
If the engine stalls and the security light flashes, wait until the light stops flashing before trying to restart the engine. Remember to release the key from START as soon as the engine starts.
If the engine is running and the security light comes on, you will be able to restart the engine if you turn the engine off. However, your Passlock system is not working properly and must be serviced by your dealer. Your vehicle is not protected by Passlock at this time. You may also want to check the fuse. See Fuses and Circuit Breakers . See your dealer for service.
In an emergency, call the GM Roadside Assistance Center. See Roadside Assistance Program .