the alarm sounds like the one that warns of objects behind the car when you're backing up. Just a simple dingdingding that won't quit whenever the car is not in Park.
the rear sensor was pushed in, so we pulled it out so it was in position to detect rear objects. There was no change in the sounds, off only in Park. also another alarm sounds when moving: slower and less frequent lower rings.
we haven't any way of checking codes
you did a good job of diagnosing my problem, which proved to me that the job was to tough for me to handle. I took it to a mechanic.
Thanks for your help.