Code P0450 help

I keep having the check engine code P0450 come up, every time it comes up though is when I fill my gas take up, it stops coming on around when a quarter of tank of gas is used. From then on it stays off till I fill up again. Is this a wiring harness issue, or a sensor issue?

 

Could be either one then it might be a problem with pressure building in the tank when full .

Maybe the vent is below the liquid level till the level drops below 1/4 tank.

How long have you had the problem??

 

Welcome to TacomaWorld
Never pump gas after the auto shutoff stops the pump.
No topping up on all 4 cylinder trucks because the charcoal cannister is mounted above the fuel tank and can get flooded with fuel while pumping the tank AND filler neck full of fuel.

 

To answer both y'all it has happened fairly recently, I have had the engine code trip that once or twice. Two years ago, but recently it has been a constant issue.

I do pump the gas after the auto shutoff but my engine is a 6 cylinder. I also have done this for years prior with no prior issue so I personally don't think that would've caused it.

It is nice to be back on Tacoma World again, decided to come back after a while because this place is just too awesome.

 

this is a good explanation... https://www.obd-codes.com/p0450

evap codes are notoriously difficult to find and fix. If you don't live in a state that requires emission testing I wouldn't worry about it too much, as you have seen, it is self "fixing".