I disconnected and cleaned the battery terminals on my 2006 Monte Carlo SS. I reattached them, checked for tightness, etc., then inserted the key and turned it to start the engine - no start. Just a series of lights on the dash that normally come on when I start the car. There is no blinking security light on the dash, although it does appear with the other lights when key is turned to accessory. Now, the car is locked in park, and the key cannot be pulled from the ignition. The lights and radio, etc. work fine.
According to someone I know who is an investigator for an issuance company-and has knowledge of GM security systems - newer cars like my Monte have a transponder system, rather than VATS, Passkey or Passlock I and II. Apparently my '06 is a hybrid Passlock III/ transponder anti-theft system, most likely because it was built in March of that year. Later manufacture dates and the '07 models came through with transponder only. The investigator told me this info based on my Vin# and the manufacture date on the drivers side door jam. That said, my car could be reprogrammed by turning the key to accessory and leaving it there for 10 mins, then rotate the key back to off for 5 seconds, then repeat the same process 2 more times. After the third 5 second count in the off position, the car should have fired up, but nothing. I still have power, can still hear the fuel pump, just no start, the key still locked in the ignition. According to my acquaintance, the car will hold enough residual power to store the matching code for the key in the computer, for at least a couple of hours after disconnecting the battery. It only took me 15 mins to clean and reattach the wires. All I can think of is that I accidentally sparked my socket wrench against metal when I was tightening the positive terminal, but that shouldn't have been enough to do anything should it?
I am at wit's end, I've checked the forum for a solution, and there are none pertaining to my car. I really don't want to f_ck with the electrical system to bypass the anti-theft system. Thanks for any help in advance.

 

You said you have no security light on and you can't get the key out of the ignition? That sounds to me like a faulty ignition switch. Although I haven't had this problem with my Monte, I have had this exact problem with other GMs and other cars I've owned. I don't know for sure that your ignition switch is the problem, but it sounds that way to me!

 

It's not the ignition switch, there's a solenoid or some other gizmo that locks the key into place as another wonderful byproduct of the anti-theft on the '06 and '07. Thanks.

 

I am having the exact same issue right now. Did u ever get this resolved and what was the fix?