Someone attempted to steal my car. the key still fit in the ignition and will turn but the car will not start. How can I get my car to start?

Could be the ignition switch was damaged in failed attempt to possibly steal the car. U might just have to replace that switch.

You have two choices, you can purchase a new ignition lock cylinder (costs between 150-200 at most any part store) and take it to a lock smith with your original key to have the pins changed to where your key operates the new lock cylinder. And then have it changed out. Or you can take your car to a mobile audio store that installs aftermarket remote start systems and have them bypass the PassLock anti theft system. Cost should be about the same either way, may be just a but cheaper for the bypass, but then your car will be more vulnerable. If the PassLock had been bypassed when they attempted to steal it, it might be gone right now.

Is because the ignition/column and theft module do not match, or maybe damaged theft system during the attempted theft of truck. You can bypass tho.

http://vatspasslockpasskeysecurityhelp.yolasite.com/

I think you have to pull the airbag and steering wheel on most all gm models with switch in the column

The vehicle isnt reading the chip in the key. Your best bet is to take it to a professional. This is common if a valet key is used. Make sure you are using the correct key.

Just turn the key on, if that doesn't reset it you have a failed part and will need the help of the dealer

TURN IGNITION KEY TO ON POSITION FOR TEN MINUTES UNTIL SECURITY LIGHT DISAPPEAR,THEN TURN OFF IGNITION SWITCH FOR 5 SECONDS THEN START THE ENGINE.

On many vehicles there is a rod that runs from the key switch to the actual ignition switch, usually mounted lower on the steering column shaft. If this is maladjusted from the installation of the key switch, or has been broken due to the attempted break in, it could in fact be the problem. I am not directly familiar with that particular truck, but from the symptoms described, I would start there. Good luck.

Is there a security light on, if it is then you have the anti theft working thinking someone is trying to steal the car. If you have the second ignition key's with you try it.  If not try this, it takes about 30 min to do. 30-Minute Learn Procedure 1. Turn ON the ignition, with the engine OFF. 2. Attempt to start the engine, then release the key to ON; the vehicle will not start. 3. Observe the SECURITY tell tale light. After approximately 10 minutes, the light will turn OFF. 4. Turn OFF the ignition switch, and wait 5 seconds. 5. Repeat steps 1 through 4 - two more times - for a total of 3 cycles of 10 minutes. 3x10 = 30 minutes. The vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch turn from OFF to CRANK Important: Turn the Ignition Switch OFF. The vehicle learns the Passlock Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle. 6. Start the engine. The vehicle has now learned the Passlock Sensor Data Code and/or password. 7. With a scan tool, clear any DTCs if needed. History DTCs will self clear after 100 ignition cycles. Without a scan tool you may have momentary starter interruptions while history clears itself. Good luck and hope this helps, keep me posted, be glad to help