Ever heard your fuel pump running long after shutting truck off?

I have a 2019 TRD-OR. Yesterday I went into the garage about 5 hours after driving my truck. I heard a continuous buzzing sound. It was hard to localize the sound but it sounded like it was coming from the underside rear half of the truck so I thought, fuel pump.

So I opened the gas filler door and the sound changed but still continuous. Then I opened and re-closed the filler cap and the sound changed again. This is why I'm thinking it was the fuel pump.

Then I got my key fob, got in the cab, and pushed the starter once (without my foot on the brake) and once more and the sound stopped. Then I shut it off completely and I think it has not re-started since then.

Anyone ever heard this before or has some info on what this is and what it means? For all I know, this has happened before and this is just the first time I've heard it. Not sure on that.

 

Normal. It’s the evap canister purging.

 

Yup, normal. Does it on my tC too. Weirded me out the first time I heard it, but it's listed in the owners manual.

 

Thanks for the replies. When this happens, how long is a reasonable amount of time for the sound to continue? 5 minutes? 30 minutes? Hours? It just seems odd that I heard it about 5 hours after shutting the truck off from about a 20 minute drive. I don't know whether it just started right before I heard it or was going on for the entire 5 hours (and the battery drain thereof).

edit: Ah, found it in the 700 page owner's manual:
"Approximately five hours after the engine is turned off, you may hear sound
coming from under the vehicle for several minutes. This is the sound of a fuel
evaporation leakage check and it does not indicate a malfunction."

The key was knowing to search for the word 'evaporation' so thanks for that.

 

This is a page from my 2nd Gen repair guide. I'm sure the 3rd Gen is similar. The pump is pretty small and only moves air so I'm sure there is little amperage being drawn for the short time it's on.

Edit: Sorry, I thought I just copy/paste one page but it's the whole stupid evap section. Just don't hit "print". ;-)

 

This.

Had the same experience shortly after I bought mine - was out in the garage hours after I got home and heard the sound coming from my truck. Started digging through the manual and found the blurb that convinced me that I hadn't stumbled into Skynet's moment of sentience.