Hey, I bought a '95 Monte Carlo Z34 at some point last year, and I was wondering how I could bypass Passkey II for it. The car has a janky plunger button wired up (turn key to on, then depress the button and it fires up) and my dad believes it's because the previous owner removed the factory radio (triggering the anti-theft) and cut the wires to install an aftermarket radio. (why he did this, I have no clue, radio could've been busted *shrug* either way, there is definitely a better way to replace a radio than cutting the connectors off.) Removing the radio probably could've tripped the security system, deactivating the ignition switch, and thus, the plunger to bypass the ignition switch. To be clear, the car DOES start, and it has the original two keysets and one of the fobs. (it came with two, but the halves of the spare one wouldn't stay together, so it was thrown out) Key fob still works, so it likely still has the factory security system. We just wanna know whether the security system can be bypassed or not, so we can check and make sure it's not a bad ignition switch.

 

Actually on the Gen 5 Monte Carlo the passlock only makes the radio inoperable(if stolen) if it had been set up to do that. I have had a 96 that my son used and I currently own a 99 if there was to be an issue with that He surely would have activated that problem.
The ignition key has a little bump on it that once it is inserted in the ignition triggers the security device and makes it start. I have read that they can go bad once in awhile.
You can purchase new key fobs and reactivate them real easy.
I am thinking if you wanted the key to start the car you might need to put in a new switch and matching keys.
I have the service manuals for the 99 and they are great source of information. I will try to find something on this subject and get back to you on it.

 

Thanks for the reply and the help. I've investigated Passkey II/Theftlock a little further since I posted this thread. I don't have contact with the guy i brought it from, but I now have an idea of how everything went down. He replaced the PCM at some point, so I believe what happened is he tried to start it, and it wouldn't start, with no clicking of the starter because the starter's good, and since he doesn't know anything about actual mechanics, decided to replace the PCM. Still didn't start, so probably went to the 5 buck plunger when he realized an ignition switch was 60 bucks. And then, the radio wouldn't work (he used a used PCM with a different VIN, so when the theftlock interrogated for the VIN, it got the wrong one back and bricked itself), so he pulled it out, cut the connector, and was going to wire in the new one, but didn't get time and didn't want to mess with it. (the aftermarket radio came in the back seat, and wires were hanging out of the dashboard in the place of a radio- that should've been my first warning sign) We DID wire in the new one ourselves, and it worked perfectly fine until the turn signal switch went bad. Apparently you can remove and replace the ignition switch without taking the steering wheel back off, so I'll probably try that in a month or two, given that the car still starts and runs with the plunger.