Puzzled - "Humming" Noise Under Bed?

Same thing here

 

This just happend to me too! I was freaked because I just did some suspension mods. Checked here first tho. All good though apparently

 

There is a vacuum pump that keeps -7 psi pulled on the fuel system at all times the key is off to stop any evaporation. Thats why it says if you are going to put your truck in storage for more than 30 days, unhook the battery. When you start the truck it pressurizes the tank to about 1 psi vacuum so you won't get vapor lock, that's why if you leave the cap off it goes into limp mode.

 

My wifes Rav4 does that...good thing it gets used daily otherwise I'd think it'd run the battery dead over time....

 

Your on the right track but actually it only draws vacuum during a leak test. It pumps up some vacuum and then sits back and waits to see if the vacuum bleeds off.

The evaporation is captured in the charcoal canister before it gets to the atmosphere. It doesn't actually need vacuum all the time.

It's kinda weird to hear it wake up like that. Evap systems have come a long way since the 80s/90s

 

I dunno man just relaying what Toyota corporate told me when I made modifications to my tanks breather system.

 

What kind of mods?

 

Just heard this on mine too and wasn't sure if it was the alcohol or what. My wife and I were out there looking under the truck like wtf is it doing haha

 

This was a fun surprise while camping in my truck bed. Freaked me out, 3am, 10 hours from home. Good to know it's normal. Still it's a pretty annoying way to wake up.

 

Same experience with my 2014 TRD, very glad to find this thread and see it's not a problem!

 

WOW. glad I found this thread. My wife heard it several times while my 2019 Taco was in the garage. It scared her enough to think a fire might start! You all are the best!

 

Figured this was some diagnostics, glad I found this thread.

Does this ever go away or can you stop it? Super annoying when camping.

 

Disconnect battery?

 

Could definitely install a switch on the battery. Thanks for the idea.

Seems crazy that this will always happen. I camp a lot and hearing this thing at 2 am fucking sucks.

 

The pump is powered from the ECM. So yeah, either disconnect the battery or pull the fuses that power the ECM. The details of what this test is doing is the 1st attached. It's a complex system. The schematic showing the pump being powered by the ECM is the 2nd attached.

 

Problem: Humming from below bed.
Solution: Provided bed with song lyrics.

Okay, so that's not nearly as funny as the airline mechanic's report book, with the pilot notification and the mechanic's resolution:
P: Target radar hums.
S: Reprogrammed target radar with lyrics.

 

Good information.
However, it is for the 2GR in the 3rd Gen trucks.
I’d say the same principle applies.

Again, great info. I haven’t seen much on the 2GR

 

I just freaked the hell out on this one. Googled it and this thread came up. Been about 4-5 hours since it last ran. Sounded like a dildo shoved up under the bed somewhere. Just went off. 2019.