I have a 96 DeVille, unfortunately I lost the only set of keys I had for the car.

I had the Cadillac Dealership make me a set of keys using the VIN number of the car, only to find that the key was not the same as the one I had for the car (visually the key was not the same) so the ignition did not turn.

I believe the person who owned the car before me had the ignition cylinder changed at some time.

I was wondering; if the cylinder has been changed, does the VATS code have to stay the same for the car no matter what or can the VATS code be changed as well?

 

It is unlikely it was changed. VATS modules don't fail as often as lock cylinders do. Key code will change but VATS code stay the same. To change VATS code requires new VATS module, VATS code burns in to it as soon as key is turn to crank the first time and can not be changed. Dealer should have a tool to read and bypass VATS to verify what code is. It will still require key that will turn in ignition to cycle ignition switch. Once VATS code is verified correct blank can be cut, to correct key code. Replacement cylinders come with "pelletless key" which is the pattern for new VATS key.

 

When I had the incorrect key made the dealership printed me a page with the original VATS code using the VIN.

I wanted to get a blank key from eBay because they are cheaper there then have a locksmith figure out the tumblers and cut the key from the blank I bought.

Having the locksmith figure out the code and making the key is $180, while using the key from eBay and having the locksmith make the key is $100.

I would love to save the money but was warned that the VATS keys sold on eBay may be no good.