The security, antitheft or lock picture/icon 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 misinterprets 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 explains it pretty well.
http://www.diy-gm-security.com/
Have you checked your keys? I know for some cars, if you're using a spare key that has yet to be programmed into car's ECU, it will not let the car crank.
You cannot reset the ECU. A highly trained mechanic might do it, but good lucky finding one that will.
Check your other electrical components because I highly doubt it's your security system.
You know the problem is not with the battery because to had it tested how? A voltage test tells you nothing! You need to have a free 15 second *battery load test done at any store that sells new ones other than Auto Zone. A load test will tell you the reserve amperage capacity. Amperage spins starter motors not voltage.
Try using the GM HOTLINE number in your MANUAL or tw\=ow it to a working GM dealership! The HOTLINE is free advice! TRY READING YOUR MANUAL!
its really difficult
I BELIEVE MY SECURITY SYSTEM HAS LOCKED ON IT HAS NO POWER AND WON'T CRANK AND I KNOW ITS NOT THE BATTERY...
