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My son and I bought an 01 trans am ws6 auto in September. Initially ran without any problems. A few minor issues to deal with immediately such as power steering pump , alternator replaced, Oem Power steering fluid cooler delete and replace. Typical stuff I guess. 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. Next day ol dad was doing some work on his audio system 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... I have heard conflicting accounts of this. Honestly not clear on 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 realize 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? Could 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. 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..
 

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Here's a good write up on the PASS-Key II (VATS) system:


The contacts that read the key resistor are in the lock cylinder.

With regard to the starter, there is a relay in the starter solenoid circuit that requires a ground from the PASS-Key system. The PASS-Key module is part of the body control module (BCM). If the BCM sees the correct resistance from the key it grounds the relay. No resistance match it doesn’t ground the relay = no crank/no start. If the starter is cranking, albeit sounding like a weak battery, the circuit has been completed.

Then there's part 2 of the PASS-Key system. The fuel pump should always prime for two seconds when you turn the key to “RUN”, then shuts down. The PCM will not restart the fuel pump unless it receives the “fuel enable” signal from the BCM. Only sends that signal if the key resistance reading is correct.

Once the engine starts, if the resistance signal is lost or changes, the PCM will not shut down the engine, too unsafe. Sounds more like the sloppy tilt is moving the rod that connects the key cylinder to the ignition switch at the base of the steering column.

The above is based on what I know about the system up through 1997 models. I doubt they changed much, if anything after that, knowing the the F-Body days were numbered.
 
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'93 6-spd Trans Am - '96 C4
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The BCM is over at the glove box, if your son ran any wires over there, he might have disturbed the connector. Do go through all the VATS information at the shbox website Injuneer linked and click through the relevant links. It's the best write-up on the system shy of some GM Technical Document. If your son added an amplifier that required manipulation of the battery terminal, check that the connection is secure.

Welcome Aboard!
 

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Discussion Starter · #4 ·
Here's a good write up on the PASS-Key II (VATS) system:


The contacts that read the key resistor are in the lock cylinder.

With regard to the starter, there is a relay in the starter solenoid circuit that requires a ground from the PASS-Key system. The PASS-Key module is part of the body control module (BCM). If the BCM sees the correct resistance from the key it grounds the relay. No resistance match it doesn’t ground the relay = no crank/no start. If the starter is cranking, albeit sounding like a weak battery, the circuit has been completed.

Then there's part 2 of the PASS-Key system. The fuel pump should always prime for two seconds when you turn the key to “RUN”, then shuts down. The PCM will not restart the fuel pump unless it receives the “fuel enable” signal from the BCM. Only sends that signal if the key resistance reading is correct.

Once the engine starts, if the resistance signal is lost or changes, the PCM will not shut down the engine, too unsafe. Sounds more like the sloppy tilt is moving the rod that connects the key cylinder to the ignition switch at the base of the steering column.

The above is based on what I know about the system up through 1997 models. I doubt they changed much, if anything after that, knowing the the F-Body days were numbered.
Thanks for the input from both of you. Much appreciated. I haven't been able to work on it because I've been out of town. Honestly I'm wondering if it's the lock cylinder or the push rod you are talking about considering the work I've had to do on the upper column... Would replacing the cylinder potentially work? Or cylinder and the push rod? I'm not for sure what the push rod even does. Does it make contact with something as well? Is that a replaceable part?
 

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If I read the huge paragraph in your first post correctly, I believe it indicates after the resistor bypass:

- the “SECURITY” light went out.

- the starter will not engage when you turn the key to “START”.

My initial thought was a problem with the rod that connects the key cylinder to the ignition switch at the bottom of the steering column. That rod is adjustable, so you shouldn’t need to replace it.

If the key cylinder resistance reading has been bypassed, the only other function the key cylinder has is to move the rod for the ignition switch. It moves the ignition switch into the “ACCY”, “LOCK”, “OFF”, “RUN”, “BULB TEST”, or “START” position to complete the corresponding circuitry.

One possibility is the the switch is not moving fully into the “START” position when the key is turned to the “START” position.

Download the 2000 factory service manual. I think that's the latest FSM on this site:


Should be the same as your 2001.

Find the wiring schematic for the ignition switch. Identify which pin on the switch sends power to the theft deterrent relay (TDR) when the switch is in the “START” position. It's usually a yellow wire, but you need to verify that.

Connect a multimeter, set to DC volts, + lead to the pin, - lead to a good chassis ground. Turn the key to “START”. Does your meter indicate 12 volts?

YES = ignition switch and rod are OK, move to the next items in the circuit - TDR, and clutch start switch (manual trans), or transmission range switch (auto trans), and repeat check for 12 volt in and out.

NO = it's a problem with the rod adjustment or the ignition switch

Diagnosis is always less expensive than playing “parts replacement roulette”. :D
 
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