Antitheft prevents from starting car
 

Security relearn?

For his sake:

1) Put the key in the ignition but do not crank the motor, just leave it at the ignition mode (AUX) for 10 minutes.
2) Turn the key to OFF position for 5 seconds then REPEAT again 2 more times.
3) On the 3rd time, you will notice the ANTI-THEFT light on the dash will start blinking. When doing this step, turn the key to OFF position, remove the key. Wait 10 seconds, insert the key and attempt to turn over the vehicle.

I had a question mark because I wasn't sure if that was the answer. Honestly wasn't trying to be a dick just throwing my best guess out there.

Just to clarify key needs to be in the "run" position. Wait 10 min or until theft light turns off. may take slightly less or more than 10 min but no more than 15. If the light doesn't turn off you need to get the code pulled so we can help further. Also the light shouldn't flash after the third time, it should go off just like the first two.

30-Minute Vehicle Key Relearn
Important: This procedure will only relearn the vehicle keys. This procedure will not learn the immobilizer prerelease password or the challenge/response data. Do not use this procedure as a substitute for a 10-minute relearn when replacing or reprogramming a TDM or ECM. Doing so will result in a failure to learn the prerelease password and/or the challenge/response data.

This 30-minute learn procedure should be used when all vehicle keys are desired to be replaced or reprogrammed. This procedure will erase all previously learned vehicle keys from the TDM. Once the 30-minute learn procedure has been completed, any remaining vehicle keys may be programmed using the Adding Keys procedure to ensure their continued functionality.

 1. With an unlearned master vehicle key, turn ON the ignition, with the engine OFF.
 2. Observe the security indicator, after approximately 10 minutes the telltale will turn off.
 3. Turn OFF the ignition, and wait 5 seconds.
 4. Repeat steps 1–3 two more times for a total of 3 cycles or 30 minutes.
Important: The TDM learns the key transponder information upon the ignition switch transition from OFF to ON. You must turn the ignition OFF before attempting to start the vehicle.

 5. With a master vehicle key, start the vehicle. The vehicle has now learned the key transponder information.
 6. If additional keys are required to be learned, refer to Adding Keys.
 7. With a scan tool, clear any DTCs.

No worries. Chances are, OP would've asked so I tried to lay it out.

And here's the master at work :guns:

No crank
 

I recently put my car together and after connecting the battery and trying to start I get headlights and radio. Only light on the dash is the lock symbol and the Dic reads service airbag. Nothing else powers on. Do I have to do the above steps? Or did i miss a pin putting the fuse box back together?