Lost key to1999 how to over ride security for restart of

You can't. The security system and immobilizer is there to stop EXACTLY what you are trying to do, start the car without the key and security code credentials.

Your local dealership with make you a key based on the VIN Number. Then you have to reset the security system.

Or you can try a local mobile locksmith.

Or find the key. If you lost the key in the snow, look up 'Ring Finders', a global network of metal detectorists that find lost rings and keys.

fob doesnt control immobilizer key has security set up --fob is designed to open and lock doors and reset alarm ---and no bypass to immobilizer

It means the engine computer lost the theft pass code from your ignition key. This could be caused by a bad chip in the key, or a problem with the ignition tumbler or steering column wiring (many times older high mileage vehicles the wiring breaks in the steering column causing the signal to be lost intermittently). If this happens while your Buick is running, it is warning you it MAY not restart if you turn it off because a loss of theft deterrent code was detected. If this happened when the key is turned on, but engine not started, the engine will not start as the engine computer thinks the car is being stolen.

As long as you install both struts it should work.

Again, you can't. Don't tear up the column to try. You have to tow it to a dealer. It takes 2 keys to reprogram the security. They can cut the keys if the cylinder hasn't been replaced before. $400+. new cylinder $500+. Some lock smith's can do it. But not much cheaper. You save a tow bill.

sounds like the bcm may have failed, if so new bcm and new keys and programming with tech2
thats the worst case
or
wiring issue eg ignition switch
its not reading the key due to security light still flashing
the manual over ride should have worked if it didnt then i would be checking all fuses and power inputs to the bcm from the ignition switch

You can not over ride the system. This is to keep the vehicle from being stolen. You can take the VIN number to your local Jeep dealer and they will make you a new key for around $40

There is a detailed write-up here: http://vatspasskey.com . The guy is great, this was the only way I was able to save my Park Avenue. I see it applies to your model too.

key lost programing needs to go back to the dealership to get reprogramed