Electrical motor sound coming from parked truck

My truck had this small electrical motor sound coming from the rear near the gas tank. It was in the garage and nothing was on in the truck. It went on for several minutes. What is this? EVAP purge controller for fuel tank or something similar? first time I have heard this. truck is a 2010 Prerunner double cab. Truck is running fine and only has 3600 miles on it.

 

Yeah...It's some sort of emissions control/recovery system IIRC- Comes on like 3-4 hours after you shut down??

 

I figured that was what it was but was thrown off since in 3 months of owning it I had never heard it before.

thanks

 

Yep - it's some sort of emissions control thingie that activates after everything cools down or a certain amount of time has passed. It typically engages anywhere from 2 to 4 hours after the truck is shut off.

 

Emissions crap equals unecessary weight in my opinion. No telling how much all that junk weighs. I usually yank all that crap off my motorcycles..

So shoot me tree huggers........

 

its the pressure being released from the tank,next time you here it take the fuel cap off,pressure will release and noise stops.its totally normal.

 

I did remove the gas cap and the noise continued.