Strange Noise from rear of car while OFF
 

Here's one I've never experienced...

My car is in the garage. I go to throw some recycling in the garage before going to bed and I hear this weird humming noise. It sounds like a small air compressor running. I walk toward the garage door and it starts to sound like it's coming from outside, like someone is using a tire inflator.
Then I realize it's coming from my car. So I run and grab my wife's iPhone and try to take some video.
Unfortunately the video is disjointed, so there are actually 3 videos. The first interruption came from me accidentally pressing a button (iPhone noob). The second interruption came from an app alert.

Obviously, the car is not running.
You may not be able to notice it, but the noise gets quieter after I start recording. As if the (notional) electric motor has suddenly been unloaded. Then, when I put the key in the ignition and turn it to on the noise stops.
The only thing I could think of is that it's the fuel pump running. But when I turn the ignition on I can hear a completely different sounding motor turn on, which I'm pretty sure is the fuel pump.

[ame="http://www.youtube.com/watch?v=xK9J-BrnSA0"]Strange Noise from FR-S 1 - YouTube[/ame]

The squeaking in the background is my wife opening the back door.
[ame="http://www.youtube.com/watch?v=1G88rPOW7eI"]Strange Noise from FR-S 2 - YouTube[/ame]

[ame="http://www.youtube.com/watch?v=GDnk0yZR1l0"]Strange Noise from FR-S 3 - YouTube[/ame]

Someone tell me I'm not crazy...

Someone who actually owns the car can probably chime in with more solid information, but...

I recall reading somewhere (on this forum, can't find it at the moment) that the car will occasionally perform a leak test on the fuel system after the car has been off for several hours. This apparently makes an audible noise and is probably what you're hearing.

Again, I don't have any firsthand experience, so maybe someone can confirm that or offer another explanation.

Edit: Found the thread, http://www.ft86club.com/forums/showthread.php?t=16534

My apologies for freaking out. You are correct:
http://www.ft86club.com/forums/showthread.php?t=16534

I guess I should spend more time :sign0012:

Thanks for the post, I just caught mine doing the same thing this morning for the first time, and thought, "oh boy, now what?" This post makes me feel better, thanks!

Same here:w00t:

Pat

At least we know what it sounds like now.

Thanks for this post. Thought someone strapped a time bomb underneath while the car is in the driveway

It is definitely Slender Man!!! RUN AWAY!

ive had that happen too. funny thing is, i also have a CAMRY .. .and i caught it doing the SAME thing months ago and couldnt figure it out.. .now ocassionally both 'Toyotas' do it - so its kinda creepy to say the least.

Beehive/cow mooing sounds are familiar to S2000/NSX owners - especially on hot days with less than half a tank. I presumed the charcoal filter likewise here.

OTOH, your wife probably shouldn't be making squeaking noises...

I like the idea of my BRZ checking on itself in the middle of the night. Now if only it would self-diagnose the cricket sound and implement a fix.

Does the vehicle do this only once, or will it do this every day and kill the battery if I park it for a month?

I don't know for sure but here's my educated guess:
If the engineers were smart enough to have the car conduct a self leak test on the fuel system, they were smart enough to make sure it doesn't do it so much that it kills the battery.

Though engineers have been known to make mistakes! If the programming starts killing batteries I'm sure they'll release a software fix.

I just had this happen as I was getting something from the trunk. Glad its not an issue and just a leak test. Thanks!