My 2017 Camry's alarm goes off when the car is parked outside on a warm/hot day. I have been told it may be related to intrusion detection switches under the hood or in the trunk. Any suggestions on how to diagnose before getting the dealer involved?

 

Have you tried posting at Toyotanation.com?

Try changing the remote battery.

When leaving the car. open any HVAC vents to the outside to try to lower the inside air pressure that might build up due to heat.