Possible PASS Key II problem?

Need a little more info . Security fuse ????? Do you mean anti-theft ? The SECURITY light is lit on the instrument cluster ? Content theft or vehicle theft ?
Vehicle Theft Deterrent (VTD) Description
Ignition Key
The ignition key for vehicles which are equipped with the PASS-Key® II system consists of the following components:
• A typical square ignition key blank
• A resistor pellet
The PASS-Key® II ignition key has the same mechanical key cuts as a non-PASS-Key® II ignition key. You can not service the key blank and resistor pellet separately. There are 15 different ignition key assemblies, each with a different key pellet resistance value.
When you service the PASS-Key® II system, obtain all ignition keys. Verify the proper key code values withJ 35628-A Interrogator.
Steering Column (Ignition) Lock Cylinder
The steering column (ignition) lock cylinder that is used with the PASS-Key® II system contains a set of electrical terminals. The terminals are used to contact the resistor in the ignition key.
The wire routing for the contacts inside the steering column is very critical. When you service the lock cylinder, maintain proper wire routing.
When you replace a steering column lock cylinder, make new keys. The new keys must match the following items:
• The PASS-Key® II code of the PASS-Key® II system
• The mechanical cut of the new steering column (ignition) lock cylinder.


Measure the resistance of the pellet on the key , go to radio shack an buy a resistor of same value an solder into wiring harness .

pulling fuse won't work , power's the PCM as well . Plus software in the PCM won't let it start if it doesn't see input signal from the Theft deterrent module .Take an get it fix right .

There is no wire you can cut ,doing this will make your vehicle never start .
The Personal Automotive Security System (PASS-Key II?®) is standard equipment on the vehicle. The system is designed to prevent vehicle theft by disabling the engine unless an ignition key with a specific electrical resistance is used in the ignition cylinder. The PASS-Key II?® system and the universal theft deterrent operate separately. The universal theft deterrent system is optional. The PASS-Key II?® system includes the following components:
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The ignition key

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The ignition cylinder

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The body control module (BCM)

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The starter relay

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The powertrain control module (PCM)

Have it checked for DTC'S - diagnostic trouble code's . I suspect the problem is with the tdm module or the ignition switch ???? Assuming will only get you into trouble . If the PCM - engine computer does not see the right coded meassage from the TDM it won't turn on the fuel injectors or it will cut them off in two seconds . .
Buick Security Systems 1998 Chevy is the same .
Ignition Key With Wrong Resistor Pellet Code is Used To Start Engine
The theft deterrent module performs one of the two following actions when you attempt to start the vehicle with a wrong ignition key:
• There are 15 PASS-Key® II resistance ranges. The PASS-Key® II resistance may be one of the 14 valid but incorrect PASS-Key® II resistance ranges. The theft deterrent module will perform the following actions when you attempt to start the vehicle (if the condition is present during an engine start attempt or for 1 second any time after the engine has started):
• Turns on the SECURITY indicator
• Sends a password to the PCM through the fuel enable signal circuit
• The password disables fuel delivery to the engine.
• Disables the theft deterrent relay, which disables the starter circuit
• Disables sampling of the PASS-Key® II resistance for 3 minutes
• The 3 minute time period is called the shut-down period.
• Disconnecting the battery will not clear the timer sequence. The timer sequence will resume when battery power is restored.
• Inserting the proper key during the vehicle shut-down period will not start the engine. The engine will not start until the shut-down period has elapsed.
• After the shut-down period, the engine will start if the correct ignition key resistor pellet is used.
• The PASS-Key® II resistance may be correct and allow the engine to start. Later during the same ignition cycle, the PASS-Key® II resistance may be one of the 14 valid but incorrect resistance ranges. The theft deterrent module will perform the following actions:
• Enters the fail-enable mode
• Turns ON the SECURITY indicator
• Sends a password to the PCM through the fuel enable signal circuit when more attempts to start the engine occur
• The password allows the fuel enable circuit to deliver fuel to the engine.
• Enables the theft deterrent relay, which also enables the starter circuit.

Ignition Key With Correct Resistor Pellet Code is Used To Start Engine
The theft deterrent module performs the following actions when the correct ignition key is used in order to start the vehicle:
• Enables the theft deterrent relay. The theft deterrent relay enables the starter unit.
• Sends a password to the Powertrain Control Module (PCM) through the fuel enable signal circuit. As a result, the PCM allows fuel delivery to the engine.


By pass theft system .
GM VATS Key Resistor Key Security Bypass

does the DIC say "Clean Key - Wait 3 Minutes"? If so, your PASS-Key II anti theft system is starting to act up. I had the same problem in my 99 Aurora for years, until I bypassed the key resistor with a resistor pack. Google "PASS-Key II Bypass" and you should find others with the same issue. Check this link out. http://vats.likeabigdog.com/
I went to RadioShack, bought a package of different resistors for ~$10, used an ohmmeter to measure the key resistor (they differ from car to car) and then made a resistor "pack" to mimic the key resistor. Now the tricky part is that you have to take off the dash panel under the steering wheel, cut the resistor sensor wires from the ignition switch, and then solder the resistor pack in between the cut wires. Basically you're fooling the system that the key is in the ignition. It hasn't been completely fool proof (when the car is really hot in the summer, sometimes I still have the same problem - may need more temperature stable resistors), but it has been SO MUCH better than before I did the bypass.
Hope this helps, and good luck!

Your vehicle is equipped with the PASS-Key II (Personalized Automotive Security System) theft-deterrent system.
PASS-Key II is a passive theft-deterrent system. It works when you insert or remove the key from the ignition.
PASS-Key II uses a resistor pellet in the ignition key that matches a decoder in your vehicle. When the PASS-Key II system senses that someone is using the wrong key, it shuts down the vehicle's starter and fuel systems. For about three minutes, the starter won't
work and fuel won't go to the engine. If someone tries to start your vehicle again or uses another key during this time, the vehicle will not start. This discourages someone from randomly trying different keys with different resistor pellets in an attempt to make a match.

The ignition key must be clean and dry before it's inserted in the ignition or the engine may not start. If the engine does not start and the SECURITY light stays on when you try to start the vehicle, the key may be dirty or wet. Turn the ignition off.

Clean and dry the key. Wait about three minutes and try again. The SECURITY light may remain on during this time. If the starter still won't work, and the key appears to be clean and dry, wait about three minutes and try another ignition key. At this time, you may also want to check the fuses (see "Fuses and Circuit Breakers" in the Index). If the starter won't work with the other key, your vehicle needs service. If your vehicle does start, the first ignition key may be faulty. See your dealer or a locksmith who can service the PASS-Key II.

If you accidentally use a key that has a damaged or missing resistor pellet, the starter won't work. The SECURITY light will flash. But you don't have to wait three minutes before trying another ignition key.

See your dealer or a locksmith who can service the PASS-Key II to have a new key made.

If you're ever driving and the SECURITY light comes on and stays on, you will be able to restart your engine if you turn it off. Your PASS-Key II system, however, is not working properly and must be serviced by your dealer. Your vehicle is not protected by the PASS-Key II system. If you lose or damage a PASS-Key II ignition key, see your dealer or a locksmith who can service PASS-Key II to have a new key made. In an emergency, call the Chevrolet Roadside Assistance Center at 1-800-CHEV-USA or 1-800-243-8872 (In Canada call 1-800-268-6800).

Also this could helpfull: 2000 Chevrolet Camaro - Owners Manual

Hope helps.

System operation
System arms 5 seconds after switching ignition OFF. Switch ignition ON. Ensure clock LED illuminates for 3-5 seconds. If LED flashes rapidly at regular intervals for approximately 1 minute, then flashes at irregular intervals: Key code not recognised. Remove key and try again.
Programming
When
System malfunction: LED illuminates for 1 minute, then flashes at irregular intervals. Key(s) added or replaced.
NOTE: Replacement keys MUST have blue mark. Keys with red mark are NOT compatible with this system.
How
NOTE: Programming method using vehicle keys can be deactivated using diagnostic equipment.
Obtain 2 programmed keys (A and B). Insert key A into ignition switch. Turn ignition switch to position II. Wait 1 second. Switch ignition OFF. Remove key A. Insert key B into ignition switch within 5 seconds. Turn ignition switch to position II. Wait 1 second. Switch ignition OFF. Remove key B. Within 10 seconds: Insert key to be programmed into ignition switch. Turn ignition switch to position II. Wait 4 seconds. Switch ignition OFF. Wait 5 seconds. Start engine. If engine does not start and clock LED flashes: Switch ignition ON. Wait at least 20 seconds. Switch ignition OFF. Repeat programming procedure. Repeat above procedure to program remaining keys. Keys can also be programmed using diagnostic equipment

Normally, you would insert the key in the drivers door, turn left, then right to disarm and reset it. If yours is malfunctioning, you can disable it for good by doing the following:

The FACTORY ALARM DISARM WIRE IS
light green with a negative polarity at the harness coming out of the door in the driver's side kick panel.

Once Located, splice into this wire with a similar guage wire, and put it to a solid chassis ground. This terminates the OEM alarm functions entirely.

OR:

Bulb Stays Illuminated and Engine Does Not Start. If the "SECURITY" indicator stays illuminated while and after attempting to start the engine and the engine does not crank or start, this indicates that the PASS-Key II module has sensed an improper key value and has disabled the engine and set the disable timer. This specifically does not mean that the key sense circuit is open or shorted to chassis ground, refer to "Bulb Flashes and Engine Does Not Start." Remove the key from the ignition and verify that is the correct key code for the vehicle. The key code may be checked using J 35628-A and comparing the key code to that of other keys for the vehicle. After waiting approximately 3 minutes for the disable time to expire and the "SECURITY" indicator to go out, try to start the engine with a known good key with the proper key code.


Bulb Flashes and Engine Does Not Start. If the "SECURITY" indicator flashes once per second and the engine does not start, this indicates that the PASS-Key II module sensed an open, a short or otherwise invalid (value matched none of the available 15 key codes) input from the ignition key resistor input. The PASS-Key II module does not start the disable timer during this operation mode. This operation mode could also be caused by a malfunctioning power or ground circuits.

OR:

There is 2 more ways to fix the problem:

1) replace key cylinder (very difficult)

2) look for 2 small white wires encased in an orange cover at the bottom of the steering column at the big steering column connector. Cut the two small white wires and connect a resistor of the same resistance of your key chip onto the two white wires leading into the connector. Problem solved!


I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

If you car has the immobilizer system, the following might help.

The Immobilizer System protects your car from theft. A properly coded ignition key must be used in the ignition switch for the engine to start. If an improperly-coded key (or other device) is used, the engine’s fuel system is disabled.
When you turn the ignition switch to ON (II), the Immobilizer System indicator should come on for a few seconds, then go out. If the indicator starts to blink, it means the system does not recognize the coding of the key.
Turn the ignition switch to LOCK (0), remove the key, reinsert it, and turn the switch to ON (II) again.

Hope this is helpful to you.

If you just replaced the ignition switch then there are no additional procedures.The vehicle should start.If you replaced the ignition lock cylinder then you have the do a relearn.This is done by 1.attempt to start the vehicle.The vehicle will not start when key is released.Do not turn the key off after releasing it just leave it in the run position.The security light will come on for approximately 10 minutes then go off.Turn off the ignition and wait 5 seconds then repeat this two more times.For a total of 30 minutes.After the last time when you go to start it it will learn the pass code.Make sure you turn the ignition off after the last 10 minutes and wait 5 seconds before attempting to start the vehicle.The vehicle should now start and run.If not retry from the top. Hope this helps.Good luck.

It could be the key. It has a Pass lock system with the chip in the key. Have the chevy dealer service department check the key for resistance. You cannot use a "copy" key cut at the hardware store. If you get a replacement key from the dealer the car might crank and start.