Am I hearing the evap canister, fuel pump, or something else when the truck is off?

Hey,

I'm hearing a slight humming or electric motor type noise when the truck is off. It sounds like it's coming from the back of the truck under the bed somewhere. The truck is a '23 TRD OR with a few hundred miles on it. I could only find one other post saying it's the EVAP canister, but it was regarding a 4cyl. I drove the truck about 20 miles today and it has been parked the last few hours. Any idea what it is and why? I tried to search it, but maybe I didn't look hard enough. Sorry if everyone knows the answer to this question but me. Thanks

 

Emissions self test. Happens about 5 hours after parking. There's a blurb about in the front of the owner's manual.