I have a 1998 Chevy Cavalier 2.2L that my parents bought new and now I have it. 20+ years of owning it, it wasn't until a couple of years ago (on a cold day) did I realize it had a Theft Deterrent System. My parents had never had to activate it or create a passcode to turn it off. Just one day a couple of years ago when trying to start it on a cold day did I notice the dashboard light. Luckily I still had the owners manual, read about the Theft Deterrent System, and had to create a 3 or 4 digit code, enter it in first time, and then once I followed the steps of entering in the new code and try to start the car did the car start. Still SMH about why after all these years? Anyway, it seems to be a known problem when it's <50 degrees does the Theft Deterrent System want the code entered. It might seem like it's out of gas or not getting fuel but it does crank and it starts for 1-3 seconds and then dies. If the Theft Deterrent System light is on, it's most likely the Theft Deterrent System. It's gotten a bit worst lately the colder it gets (it's been in the single digits recently). The Theft Deterrent System will require me to enter the number three times before saying "SEC" on the radio but I'll have to do that >8 times until it wants to start. It has taken me ~10 minutes (of following the steps) to finally get the car started. A couple of weeks ago I called the Chevy c/s 1-800# to explain this problem and could the Theft Deterrent System be turned off. She didn't know but did say I should disconnect the battery to reset to reduce the number of times the Theft Deterrent System wants me to enter the code. That worked. She said I should call a/the dealership about possibly getting the Theft Deterrent System disabled. I called the original dealership and they said they don't work on 20+ y/o cars and go to a mechanic. I got on this forum to see if anyone knew if the Theft Deterrent System could be physically turned off or turned off with a scan tool thru the OBD2 plug. Anyone know if it can?
I hope my experience helped because from what I read so far, lots of people were replacing starters, fuel pumps, etc to what seems to be the Theft Deterrent System.

 

I have a 1998 Cavalier 2.2L (that my parents bought new). After they couldn't drive anymore, I got it. It's been a very good car. No major problems. Almost 180K miles. It had a problem of the wipers not turning off when I turn them off (unless I turned the car off and back on) but that problem went away. The horn stopped working...the mechanic said the contacts in the horn button got fried. The Theft Deterrent System decided to be a thing (requiring the creation of a passcode and then having to enter the code on cold days) just a couple of years ago. Anyone know if the Theft Deterrent System can be turned off with an OBD2 scan tool or a wire cut?

 

Please use the "New Thread" button. Do not hijack 17 year old questions. Do not multi-post the same question. Thanks.

I've moved both your posts to their own thread.

 

I found that a scan tool can't turn off the the Theft Deterrent System. Would replacing the factory radio do away with the Theft Deterrent System?