Fuel pump running on it's own

So I walked out into the garage tonight and heard a wierd humming noise. After walking around for a bit trying to figure out where it was coming from I finally realized it was the fuel pump on my truck. The keys were not in it and it had been sitting there parked for a couple hours. I know it wasn't doing it the whole time it was parked because I had been in the garage about an hour prior to this and all was silent. I got in the truck and no lights were on or anything, so I went back inside and grabbed the keys and started it up then shut it back off and the pump stopped running. It's been about an hour now and I just checked on it before bed and it's still off. Anyone ever have this happen before? For reference, it's a manual so I don't have the smart key/push button start or anything, it just has the plain old ignition key.

 

Totally normal, the truck does an emissions self check about 5 hours after you shut it off.

 

Ya I've heard it do the self check thing before but that's usually just a couple seconds and then it shuts off. This was continually running, I was out there a good 5 minutes trying to find where the noise was coming from (my garage has a bit of an echo), then another few minutes taking the stuff inside that I went out for in the first place before coming back with the keys to try starting it up. I don't know how long it had been going on before I went out there but I know it was running for a solid 10 minutes or so from the time I first heard it.

 

Was it cold outside and warm in the garage? As the fuel warms up and expands it increases pressure in the tank which will require a longer purge process. This will be more evident with more fuel in the tank.

 

It's pretty warm out today so not a huge difference in temp between outside and garage, nothing like it usually sees anyway, it was mid 40's outside and probably low 50's inside, and it's currently only got about 1/4 tank in it

 

Its in the Owners Manual, about 5 Hours after you shut it off it will run that check.

 

https://www.tacomaworld.com/threads/wtf-is-this-sound-from-rear-end-truck-is-off.308857/

https://www.tacomaworld.com/threads...ruck-hours-after-driven.582766/#post-19389359

 

Think... how can a fuel pump pump if there is nowhere for the fuel to run to?
Emissions.

 

Well I'll be damned, good find, thank you! I was aware of the self test situation or whatever it does when it's parked and I've even heard it do it before, just never heard it continue for so long which is why I was concerned. Every other time I've heard it, it was just a quick on/off kind of like when you turn the key to on without actually starting the engine and the pump primes. I guess I won't worry too much about it.

 

Absolutely normal, many covered it here well.
My truck does it and the coolant pump for the supercharger is on the same circuit. I may drive the truck twice a week at the most. The self checks don't effect my battery one bit despite it running two pumps.

Our Camry does the same thing.

Sometimes I wonder what they are saying to each other out there.

 

Fwiw I think the fuel pump only runs after the crank position sensor sends a signal (rpm). It's been that way for years, I doubt they would change it now.

 

It appears this is a system check from what I have read so far & thus no worries. I recently had this same concern on a 2014 TSS 4wd. Some notes seem to indicate this information is in the owner's manual. Well I haven't found it yet. Should you discover the location take a minute & post that specific location within the 600 pages. Thx

 

Can you provide the location in the owners manual that references the fuel pump running after 5 hrs of sitting, to perform a system check? If so, please share. Thx

 

Page 8.

 

It's not the fuel pump running, Post #10 shows what is in the Owners Manual