Check Engine Light, 2005 Taco

I had it scanned.

It says:

***************
PO456
"Evaporative Emission
System Leak Detected
(very small leak)"
***************

So how can I find this leak?
Where could it be..?

HELP!

 

This should be located in the tech chat section.

Welcome to TW Phanhtomm!

There are a dozen or more different places that an evap leak could be located. P0456 codes are the most challenging because small leaks are the hardest to find. The best suggestion I would make is to take it to a shop that has a smoke machine, and ask them to smoke test it. It is the easiest way to find the leak, and the one that will guarantee your success instead of the other method used which is to replace one component at a time until the code doesn't come back. That method is expensive! lol. One other option is that many times a small leak can be caused simply by not having tightened up the gas cap sufficiently after refueling. So did this code come up shortly after getting gas? If yes, then recheck your fuel cap.

 

In my experience, nine times out of ten this is caused by an old (or not tightened) gas cap.

 

Thank you. (Sorry I'm new here).

 

yeah, as a test. put a lil grease on the o ring or the seating surface of the gas cap. Moms 07 4runner had the same issue, through a lil grease on the o ring of the gas cap and it solved it.

 

Last month I replaced the gas cap.
The light went away for a week or so, and it's back again.
Maybe the cap is defective? I'll try to apply some grease on the seal see what happen.

 

Smoke test it

 

Hmm, smoke test (never done it b4).
How much would that cost approximately?
Do most shops do that kind of diagnostic test?