it sounds like the exact problem i had a few months ago. inside your ignition tumbler there is a little wire that breaks and causes the security system to keep the car from starting. you will have to go to the STEALERSHIP and have them give you a new ignition tumbler.it comes with a new key. they will need your VIN#. then you will have to change it and use ONLY the new key.your other ignition key will be useless. i hope this helps.good luck.

 

its on the starter

 

you guy you dont have to do any thing but go to the dealership tell tem to get the resistor number off your key, it should be from 1-15 when you get it there is a amount of ohm's off each one i have them written down somewhere ill post them later...
anyway it will just be a connector under the knee bolter (plastic under the steering colum) one there there is a orange cable you got to radio shack buy a resistor for 1.99 and when you disconnect the orange and purple connector loop the resistor around...this way the BCM(body control module) always things that pellet is in from your key, and this way you can get a key cut anywhere and it will think that since your resistor is already in its ok to start.

it sounds alot harder than it really is ill get the resistor chart later with the pics as well

 

You guys do realize that a lot of you say you had the "Exact Same Problem" but your fix for the issue is different then everyone else's? lol

 

If the security light is staying on try bypassing VATS with a resistor. Measure the resistance on your key then visit radio shack. This is for earlier cars but principle is the same: http://shbox.com/1/vats_bypass.jpg

 

Opps, here's the pelet values and how to obtain it: http://shbox.com/1/4th_gen_tech2.html#pass_key

 

Use a multimeter to test the key chip, then go to radioshack and find that value resitor. Under your dash there is a pair of wires that comes from the steering column to a plug. Unplug the plug and put the resistor in there (on the car side, not the steering wheel side). You will never have to worry about that key chip again and if you wanted you could go to wal-mart and get a key made that will work. The resistor method will NOT set off the "Security" light either, it'll act just like it use to..

 

Well, update, we got it fixed! When we jumped the pin, the starter worked, so we knew it was either the VATS, Clutch safety, or the BCM. Did the Vats resistor bypass and behold the car started! Thanks for everyones help!