I'm trying to fix my son's 91 Buick Riviera. The ignition rack got bent and was jamming up in the column. (Looks like a bottle opener almost, the gear on the other side of the key lock turns and moves it up and down to engage the ignition switch further down the column.) He had problems with the tilt, and somehow it binded up that piece and the key wouldn't turn. So I got a replacement steering column. After tearing it all apart and finding the problem it seemed easier to get a used column. I removed the steering column, replaced with another one from a 91 Riviera. Boy removing and installing that steering swivel knuckel onto the end of the shaft was a bear! I connected all harnesses, then battery, and tried to turn the key to accessory for 10 minutes in hopes in may "learn" the new resistance of the new key. It did not. Looking at both keys together it looks like a can get the old key cut down to fit and work in place of the new key. So for testing purposes I removed the old lock cylinder from broken column and plugged it in under the dash, put the old key in it and turned it to the start position. Then tried the new key in the new column. Still not even a click, so I think the VATS is still what's holding me back. I was hoping since the computer was reading the resistance of the old key, it might work. It should have anyway, but didn't. Question 1. I've seen other questions where the computer looses the original keys resistance code or reading.- How does that happen? If I had the battery disconnected for a week, would that do it? and if this is what's going on, what is the next step? Question 2. Is there anything else I can do to bypass the VATS, or get the computer to read either the old or new key again? At this point I don't think soldering in a chip with the same resistance as the key will work, or it would have started with the old key/lock cylinder connected right? Any input on what to try next or suggestions would be appreciated. Thanks in advance!

 

heres a post from another forum. this is from www.bonnevilleclub.com great forum. many knowledgable folks there. do a search there for more detail if u wish.


VATS = Vehicle Anti Theft System. It is a box under your dash that measures the resistance of the chip in your key. The chip in your key is a resistor and there were I think 6 different resistances that were used by GM. To bypass the resistor in the key you need to measure your keys resistance and buy a resistor from Radioshack that matches the resistance. Install it inline with the wire that goes to the box from the ignition switch, and then pop the chip out of the key. The car will then start without the chip. I had problems with my 95 and had it disabled. Is your alarm aftermarket? I may be wrong but I thought when the install aftermarket alarms they do the bypass. Anyway if you need it bypassed you can usually have an alarm shop do it for about $50. If you decide to do the bypass just do a search on VATS and you will find a link to the diagram for installing the bypass. Good luck.