Changed the battery yesterday on my 2001 RX300. Since then after turn off the car, take out the key-30 seconds after I open the door to get out the alarm goes off- only way to prevent this is to press unlock on the remote before I open the door and get out of the car.

Anyone have any ideas on what the problem might be? Any help would be GREATLY appreciated.

 

I would try unhooking the battery again for 10 minutes and hook back up. To reset the computer...

 

So I disconnected the battery overnight-reattached-alarm was still screwed up-then 2 days later it started functioning normally-no idea what happened-does the computer take time to reset? Anyway-it made my day!