First post here, I have a 2001 deville and it is literally falling to pieces. I seem to have been lucky enough to experience every problem people have listed on this forum. The car only has 90,000 miles and runs good, but the interior and trim are slowly disintegrating. I have had the "Service Theft System" error come up randomly for quite some time. Usually I would turn the car off and then restart and it would be fine. Well, the error became more and more frequent until it turned into every time and restarting the car did not resolve the error. I have resisted driving the car because of the stories of the cars shutting down and then not starting until a dealer serviced it. I searched and searched the internet for months for a fix and could not really find anything that didn't require throwing parts at a car that is not really worth it. Today I stumbled on a post that said to disable the theft system, put the car in valet mode. Valet mode disables the theft system, but still allows you to lock and unlock the vehicle with the fob. You also lose the ability to open the trunk remotely and must use a key. I have driven the car only twice since I put it in valet mode and have not had the "Service Theft System" error, when previously it was happening every time I started the car. I don't know if it will last, but I am happy to be able to drive the car again.

 

Well, went this morning to take it to get washed and of course the "Service Theft System" error came up immediately. Was able to get it to turn off by re-starting, but kinda blows a hole in the valet idea. Bummer