Chevrolet Repair: 2004 impala security light, security light, message security

Question
QUESTION: When I turn the key to start engine the car will not start and the "security" light comes and stays on. Is this the anti theft passlock system shutting the car down

ANSWER: Yes your passlock system is not allowing you to start the car.  You will need to have your passlock sensor replaced which is part of the ignition cylinder.  Have it repaired at the dealer because you have to relearn the new sensor.  Average cost would be 311.00 plus the parts.

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QUESTION: From what I can gather there is a Ign 1 and a Ign 2 for lack of a better description. When you turn the key half way you will get the message display window,ABS indicator but no temp or oil lights. When you turn to engage the starter or Ign 2 this is when the oil and temp indicators will illuminate. If the passlok is the problem will you still get the oil and temp indicators or will the whole system stop working. Also will the Message "security" blink or be on solid. I am wondering if I could just have a bad Key or bad tumblers in the Ign switch. Also can't a dealer tell what the voltage of my system should be by the VIN number? There should be no need to reprogram the whole car if the correct part is replaced.

Answer
Listen You need the ignition clinder replaced.  The passlock sensor is part of the cylinder.  AND NO you are not capable of doing this job yourself.  THE CYLINDER NEEDS TO BE INSTALLED IN ORDER FOR THE CAR TO BE RELEARNED.  And the best way to relearn a new cylinder is with reprogramming with the tech 2