Buzzing sound near gas tank with truck off

I recently went into my garage and heard a buzzing sound under the truck near the rear wheel well. To me it sound like the fuel pump was running. The truck had been off parked in the garage for several hours prior to me hearing the noise. My wife said she was in the garage earlier but didn't hear anything.

Has this happened to anyone?

The truck is a 2019 Tundra Platinum with about 60K

 

It’s normal.

 

Normal. It's an emissions system purge.

 

Thank you. Learn something everyday. I knew this was the place to ask such a question.

 

You're welcome.

And I should correct myself because on the Internet details matter - it's not technically a purge. The system is doing a leakage check within the fuel system to ensure there are no unintended emissions.

 

Just normal evap system operation.

 

Same buzzing. I removed the gas cap and replaced it. Buzzing quit. Dealer says it's normal