Ignition lock replacement

Take a look at the attached. You do not need to replace the ECU when you are doing this. If you are going to get a new ignition switch that already has a key but to it then you are going to have to simply perform the reprogram function. The ignition switch itself is not part of the anti-theft process. Only the magnet in the key and the receiver are the important part of this.

So that means you just need to get the key and switch then program them to the vehicle. However, they will no longer unlock your door so you will have to recode the doors and trunk to match this new key so that they all work.

Let me know if you have questions. Thanks

2006 should have a transponder style key, which is a small chip in the head of the key which is read by the vehicle when it is first inserted into the ignition to enable it to start. If you change the lock cylinder but have it pinned so the original key fits it, then it will work. If you change out the lock cylinder and use new keys you need to have a way to program those keys into the anti-theft system. Changing the ECU would only make it even worse as you would need to program it first, then program in the new keys as the key data is not stored or read by the ECU. An uncoded key will not work as the anti-theft uses the code it gets from the key to enable spark and fuel.
If the issue is lost keys a dealer or locksmith can call the company and get the codes that would allow them to either order or cut a new set of keys, then those are programmed into the system and the lost keys get erased so if someone finds them they won't work anyway.

That depends on which switch you are referring to. If you mean one inside the ignition itself like near the white connector in the image, it would need to be replaced as it is part of the alarm that reads the chip in the key. If it is the switch above it that control other items then that can be repaired at another time. If it is the part on the housing where the key cylinder goes it needs to be programmed to the system as well.

That is because the parts are not interchangeable. There is no way to disable the immobilizer, it is part of the ECU and unless it is programmed for the vehicle it will not work. You simply need the replacement ignition assembly for the Chevy, then have it coded into the ECU that was in the car. The part from the other car is not going to work because each make has a set of codes they use for their cars. So if the vehicle is a GM, even if it was re-badged from some other company, the ignition and ECU are coded to GM.