My ignition on my 1999 Tahoe was vandalized, and the Anti-theft is
after my ignition was vandalized, Im worried about the anti-thef system being a problem starting my Tahoe. Is there anything special I haveto do after I replace my ignition?
Your 1999 Tahoe may be equipped with GM's Vehicle Anti Theft System or VATS. The VATS system is composed of a set of contatcs integrated into the ignition carrier, which reads the unique resistance value of a resistor embedded within the key.
When you attempt to start the vehicle the Tahoe's VATS module reads the resistance value from the key. If it does not match the programmed value the VATS module will command the Powertrain Control Module (PCM) to disable the injectors and the spark system.
If you change out your ignition tumbler, you will have to use the new keys, which contain different resistance values! This will prevent your Tahoe from starting.
But all hope is not lost. The most expensive and easiest option would be to have a dealer change out the ignition and use their Tech2 tool to reprogram the VATS module to the new keys. This takes less than 10 minutes.
The cheaper and more time-consuming option is to attempt to use the owner key re-learn procedure. The steps are as follows.
Good luck! Keep us posted.
E Carson's answer is perfect but I would like to add to Step #3. If the Security light does not flash, the small white switch located on the top of the lock cylinder bore may have been damaged. That switch has a small white button that gets pushed upward when the key is inserted into the lock cylinder. Sometimes that button gets shaved off if the lock cylinder is forcefully removed. Without that button the Passlock System will not know there is a key in the switch and therefore it will not enter the relearn. The small white switch is part of the steering column wiring harness and not sold separately but, you can go to any self serve wrecking yard and remove the switch from the column by pushing the tiny TAB at the back of the switch IN while you rotate and lift the switch out of the hole. Then cut the wires long enough so you can crimp or solder them back into your vehicle. There are so many GM vehicles they don't mind you buying the switch separate, just make sure the switch works (bring and OHM meter)and the tiny tab is still there and the button is not shaved off. This is for the PASSLOCK SYSTEM as described in E Carson's answer.