NHTSA Complaint #11478071 — 2017 TOYOTA HIGHLANDER

My Highlander was off and parked in my driveway. I was inside my home and I heard what sounded like a car alarm that was cutting out. I went outside to find out it was my car. However, it wasn't the alarm. It's a completely different pitch/tone that the car horn or the panic button. I proceeded to unlock the car, turned the car on and off a couple times, honked the horn, opened and closed the hood, etc and whatever sound was going off continued to go off even while the car was on. Whatever it was sounded like it had a short in it. Even my neighbors came out of their home. The sound eventually stopped and I went inside. 20 minutes later the sound started again. After it stopped, it happened again, for a short period. It was on a Saturday after dealerships were closed. The next day it happened again in the evening. It stopped right as I got outside. It's a nusiance to myself and my neighbors, it's loud, it's embarrassing, and the fact it continues to sound when my car is on concerns me because if it starts sounding while I'm in traffic or on the highway, it could cause major safety issues. No lights on the dash, battery tested good, literally no explanation.