When I came home today around 2pm, the alarm was going off on my 2000 Honda Civic. I turned the alarm off and after a few minutes it went off again. this happened a few more times, till I decided to move the car from the busy main street in front of my apartment building, to a quite gravel parking lot behind the building. So far it's been about 25 or 30 minutes and it hasn't gone off.
I was googleing around and ran across this explanation for a different car:
The most common reason for alarm falses with heat is the hood switch. The expansion of the hood can trigger the pin switch to activate. You can try adjusting it or disconnecting it and see if it fixes it. My E46 also had this problem, but I never got a chance to fix it.
I was wondering if anyone had heard of this type of thing in general? I was thinking that maybe the vibrations caused by passing cars, plus heat expansion at the hood might be why it was going off on the main street, but not parked in back?
Although I doubt it's relevant, I had the engine replaced two days ago.
EDIT July 28, 2016
OK, so at this point I'm sure what's causing the problem. It happens only during the middle of the day when it's hottest out and the car is parked on the main street. It seems the alarm at that time is being set off when city buses go by. I was sitting in the car as one went by and I could feel the whole car shake.
So I guess the question is how can I reduce the sensor's sensitivity a bit so it's not set off when the city buses go by.