I bought a 2000 Civic LX recently and it has suddenly been giving me a set of high pitched dings after turning it off. They last about 10 seconds, then stop. The lights are off, the key is out of the ignition. It was a rapid ding-ding-ding. Now it's become a slower ding-ding-ding. No warning lights come on and it only happens after a trip, never before or during. I am mystified.

 

Does it have an aftermarket radio, especially a Sony? I had one that would beep every time it was turned off, the manual said that was to remind you to take the faceplate off.