Black plastic box under the car

[desktoprover]

Hello everyone,
a few days ago I parked my 2009 Vibe inside my garage. During the afternoon, I went back to the garage for some work. I noticed a strange noise coming from the Vibe. I started searching the source of that noise. It turned out to be coming from the inside of the black plastic box that is mounted under the car near the back left wheel, the big one. It was like an electrical noise or a small electric motor. It stopped after a few minutes. The next day the same thing happened! Anyone know what is inside this box or what is it for? Is it normal? I just want to make sure this is not something that will drain my battery. If I wouldn't have parked the car inside the garage, I probably wouldn't have noticed that noise.

Thanks.......Sylvain

[joatmon]

My vote is for the charcoal canister. It's part of the evaporative emissions control. Pretty sure there is some kind of vacuum pump that will kick on some time after the car has stopped to put a vacuum on the gas tank, to keep reduce gas vapors leaking into the environment. Can't say for sure, but seems like the charcoal canister can capture the gas, which doesn't get filled up because some air is pulled through the canister to the intake when the engine is running.

Pretty sure the sound you heard is normal, the way it was designed, and nothing to be worried about

[desktoprover]

Thanks for your help joatmon! It looks like you figured it out!

[Derf]

Link to audio of the purge system running. Also caught me by surprise. The manual did not mention this behavior, their was a supplemental tag placed in car noting this behavior, appears the original owner tossed the tag.
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[vibenvy]

Totally normal.

From the 2009 owner's manual...

Driving and Operating 8-15
Evaporation Pump
The vehicle is equipped with a vacuum pump for the fuel evaporation system. This pump performs a fuel evaporation leakage test approximately five (5) hours after the engine is turned off. You may hear a sound coming from underneath the rear cargo compartment for several minutes.

The noise is normal and does not signify a malfunction. See your dealer/retailer with any questions.