Colleen R. 10/6/2012This event happened last night and I went out this morning and it started right up! The security light wasn't flashing either. Weird.
beharper1 10/21/2012your going to need to replace your ignition switch. i had the same problem. go to www.apdty.com they are $69.00 takes about 45 min to replace it. if you know anyone that can work on a car don't pay for a garage to do it. it this is just starting to happen your lucky mine was doing it for a long time. if you have any questions call i can tell you what i did. i hope that helps. brian firstname.lastname@example.org
judd0081 11/1/2012The security, antitheft, or passlock light is a visual indication that something in the car's antitheft system is failing. In most GM cars and trucks there is a hidden system that most people are unaware even exists. From the moment you put your key in the ignition, there begins a constant line of communication between your key's security chip or transponder, to the ignition's lock cylinder, and then to the car's TDM (Theft Deterrent Module). These 3 parts are in CONSTANT communication. If the key is in the ignition, then these parts are sending signals to each other. The security light illuminates when that signal gets broken, even just for a second. When the signal breaks, the car misinterperates this as an attempt at theft and goes into antitheft mode. The car thinks its being stolen or hotwired because it is not getting that signal from YOUR specific key. This is why the security light turns on and shuts down your vehicle.
This link may help you find ways to bypass this or fix it yourself.