Weird noise when ignition off

I have a 2014 Off Road 4x4. Yesterday I walked out in my garage and noticed a noise coming from under the bed of my truck. The key was in the ignition and the was in the off position. It sounded like a pump or fan running. I crawled underneath and couldn't really pinpoint where it was coming from. I cranked the truck and turned it off and the noises stopped. Anyone ever heard of this? Maybe some sort of electrical snafu? Fuel pump running for some reason or the rear differential servo? That's all I can think of that would be in that area that would make that kind of sound.

 

Evap system self test... Normal.

 

i think its the gas tank fume pump,or whatever its called.

 

Thanks for the quick reply fellas. I've had the truck for about 6 months and never heard this before. Just glad it's not some electrical anomaly.

 

Normal. My Venza does the same thing. Had to call the dealer first time I heard it in the garage.

 

Good to know. I have the same year and model and have not heard that before. Will know what's causing it if I ever hear it now.

 

I tell people it's just my turbo chargers winding down