My son and I bought an 01 trans am ws6 auto in September. Initially ran without issue. A few minor issues to deal with immediately were power steering pump , alternator replaced. Oem Power steering fluid cooler delete and replace. However, the tilt steering had an extreme issue where it would have severe play lto the point where it would effect positioning, hi-low beam switch, turning signal, and key ignition which I realized after research was common. I subsequently replaced the pin with the oversized options available without fail initially. But after a few trips out the road the left side pin started working lose and causing the same issues. Again after some research I saw where a couple guys were using JB weld to hold the pins into place at the lock housing. So I tried that. Works great. However my son drove it out road and back. Parked it l. Next day ol dad was doing some audio work on his amp and realized that it wouldn't turn over. Noticed the security light was on and when you went to crank it acted like the battery was dead yet the head unit still worked as normal. So again, after looking around I semi determined it was the vats system. So I did my do diligence, measured the ohms value of our ignition key (680 ohms) and did the vats bypass. Got the security light to go off but still won't crank at all... Now I have heard conflicting accounts of this. Honestly not clear in how the car would react if the vats wasn't reading the key. Would the starter crank? Or would it crank the engine but shut off the fuel pump? Either way, I put the key in, security light goes off, pretty sure i can hear the pump charge up. But the starter won't engage. Assuming that I was successful with the vats bypass due to the light going off... I realized that the cylinder lock does a few different things beyond sending the reading of the resistance value of the key to the pcm. Mechanically is there anything that the ignition lock cylinder does that sends signal to the starter? Couldn't the ignition cylinder be screwed up and not making that contact? I mean In my head I am assuming that it has to be something in the upper steering column that I have messed up when I took everything apart to put the tilt pins back in place. I mean, the key cylinder itself always acted squirly anyhow. Ie. Depending on tilt position would shut engine off, would almost spin all the way around, ect... Any kind of help would be appreciated. Honestly I'm kind of at a loss...

 

VATS in 4th generation f-bodies is in the BCM (rather than the PCM) and disables both the starter relay and the fuel enable signal to the PCM when activated. However, if the security light in the instrument cluster turns off after the normal bulb test then you can be fairly certain that VATS is not the issue here.

The ignition cylinder is merely mechanical other than a pair of contacts which passively connect the resistor pellet on the ignition key to VATS. The actual electrical ignition switch is down the column, operated by a rod that moves when the ignition cylinder is turned. It is possible that the cylinder could cause starting problems but only in a case where it's not properly moving the rod which activates the ignition switch (e.g. the rod is binding with the cylinder or perhaps is bent).