noise from under car

[Frank Necrosis]

I have noticed a noise coming from under the rear of my yaris a few times this week. It happens when the car is parked. Nothing is turned on. In fact, the car has been sitting for several hours without any use in the past 5 hours or so.

The noise sounds like a very small piston type of pump or compressor.

Any thoughts???

[BLH]

Normal.
About five hours after you turn the car off.
A small pump is run as part of the Evaporation System Leak Detection tests.

It is mentioned in the Owners Manual.

[mirapatec]

I have also noticed this about 5 or so hours after my last drive. As BLH said, this is normal. There is absolutely nothing to worry about.

[yougojay]

It happened to me again, 2 nights in a row, a few weeks ago. I took the recyclables down to the garage one night after dinner & it started humming along, same thing the next night. Happens pretty much like clockwork about 5 hours after you last drive it. :eek: