Why does Truck "self diagnose" fuel system?

Walked into garage last night and heard relays on truck clicking and fuel pump or something running by themselves. It had not been running for hours and I read somewhere in manual this was normal, but what happens when it decides the test is unsuccesful - will it start the next day? What is it really doing at night all alone in my garage?

 

Gremlins!

 

Maybe tomorrow it will have coffee and doughnuts made for me!

 

Wouldnt that be nice.

 

Its just a fuel pump check. It will shut off but you will have a check engine light when (or if you can) you start your truck

 

thanks! - but if the truck starts, isnt that a good enough fuel pump check? I guess I dont fully understand the reason for extra (expensive)shit installed to go wrong , just to perform an obvious test.
I Love the truck, though!

 

well it prepares for the next start. Im assuming. Its just one of those Toyota things that have very little explaination.

 

Probably just makes sure there is fuel in the line, cause after a few hours it probably drains back into the tank, so it re-primes the line.

 

Swing and a miss for me!

 

Face it.
we are slaves of the Tacoma's.
Do as they say or we are all doomed!!

 

I'll buy that - Thanks all!

 

Hmmm, i wonder what else it is doing while it is all by itself in the garage...

 

It has to be the vapor recovery processed in your fuel tank. Remember those fog lights mod when the lights will come ON for a few minutes like four hours after turning the engine off? This is it, and is normal.
Take care
vbibi

 

I wonder if it they could make it do the laundry or mow the lawn. That or put money into my bank account.

 

Again Chris was the closest. As stated in the book, about 5 hours after being off the EVAP system performs a self check to make sure no leaks are occuring. If any "small" or "gross" leaks are detected the check engine light will be on the next time you start your truck. Safe to drive but you won't pass a smog test. Remember now, tighten those gas caps....

 

I think its too smart for its own good. Just spent 110.00 for 1 spare key. I would rather pay 3.50 for a non-theft proof version and take my chances. Conceal carry is a much better theft protection device! Still a cool truck, though.

 

^^^ agreed

 

You never leave your truck? I don't think the key is intended to prevent carjackings.

 

The real question is; if the fuel pump relays are clicking in the garage, and no one is there to hear it, does it really make a sound?