I just went through this problem and tech said he had to reprogram security. Started up fine when done..

 

I have a 2011 express 1500 and just yesterday the anti theft light came on and truck won’t start or crank. Tried all methods to bypass nothing worked. I even got a new key from Chevy dealer with no luck. Light stays solid on with no crank

 

Did you resolve this issue? I have the same symptom with our 2014...
Gary

 

need your help! we have a 1998 chevy cheyenne c2500hd. my man was changing the ignition lock cylinder and noticed that the wires broke off at the connector where it plugs up by the ignition lock cylinder. the way they broke off kept them from being able to be spliced back to the connector. this set off the passlock security system. he tried to bypass the system using a resistor. it cranked and ran fine last night but now today nothing. the radio will come on but he is not getting 12 volts to the ignition. no dash lights come on...nothing. i plugged the scanner up to the truck and when it test each system they all say not installed. the scanner cant even detect the systems on the truck. any idea what they problem is?

 

maybe try replacing the broken part, instead of reviving every ancient thread on this forum?