Hey guys. I just replaced an old ignition key lock cylinder that was getting sticky to turn. I can turn the engine on just fine and there's no security light, and when I turn off the engine and remove the key everything is normal. But when I open the door it starts beeping at me until I shut it again. It's the same behavior as if you were to have the key still in the ignition and it's trying to warn you about it when the door opens.

02 Monte Carlo LS (non-factory radio, but I've been using an adapter box for years with no problem)

I doubt it's the security code, but I plan on letting it sit for 10 min with the key in the ignition just in case. Any other ideas on what it might be? Thanks in advance.

 

You didn't accidently leave your parking/head lights on, did you?

 

Lol I had to go out and check just to make sure. The lights are off, so that's not the issue.

 

If anyone finds this post in the future, the issue resolved itself over time. I think it had something to do with the computer learning the security code.