Bijan41

I have a lexsus rx 450h 2011. The alarm has started goin off mostly at night. It has done it 5 or 6 times in the last two months. Once it was during the day. It goes off for 5 seconds then it stops. The doors remain unlocked during this. I have contacted lexsus they say to try turning the sonar off when locking the car but i cant do this all the time as i forget. They wanted to know if there is a problem with the sonar. What do you recommend.