I have a 2018 fusion hybrid with 89000 miles on it, it has started making a beeping sound every 10 to 20 seconds. I unhooked the 12 volt battery and it had no affect as it continued with it disconnected. I ran a scan with a topdon scanner with no codes showing, and no warning lights displayed on dash. Any idea what would cause this? I also checked and this happens whether the car is on or off.