P0446 Solutions Anyone?

[Atoyot Rennur4]

Removed the canister today and attempted to test with two vacuum pumps. I have a 2001 and the tutorial was for an earlier year. I have more hoses/fittings. I am not sure if I tested properly. I could acquire vacuum on both gauges and vacuum held. The valve actuates when powered. I do not think there is any crack in or leak in the canister. While the canister was removed we decided to disconnect the lines under the hood and blow air through them. Nothing came out the back. Both lines were rotted and broken shortly after they turned to rubber. We took a miniature plumbing pipe cutter and cut both lines and purchased new rubber hoses long enough to reach the canister. We put it all back together and will go thru the drive cycles again to seen when or if the CEL comes back on.

 

[Atoyot Rennur4]

440, 441, 446 Fixed!

As mentioned in previous threads. We pulled the gas tank to inspect, clean, and paint the frame. We found the gas tank had a broken/rusted fitting at the top. A hose was supposed to go to vapor canister. There was also a place where there was once a bracket on top of the tank where there was a small hole. We replaced the tank. We also fixed a accordion style hose that went from overfill valve to canister. A couple of drive cycles later CEL and codes were back.

We pulled canister again and attempted to bench test. It appeared to be fine and valve clicked when energized. Further inspection, blowing air from engine compartment thru the main lines feeding the canister revealed both front to back lines were rotted and broken by the rear wheels just before they turn to rubber. We cut them off with a tubing cutter and put on new longer rubber lines. We used two different size rubber lines. One a little bigger to go onto the bigger metal line and one a little smaller to fit snuggly on canister. We joined them with a little plastic reducer and used clamps. Using a little petroleum jelly made slipping the hoses on much easier.

OBD now shows EVAP is OK. Still waiting on catalyst not ready but in CT emissions will pass if one OBD is not ready.

No more unburned gas smell out at the rear of the vehicle.

Easy diagnosis and inexpensive fix with determination and two people.

 

[4racer]

I replaced everything but in the end I needed a new charcoal canister.

 

[Atoyot Rennur4]

Passed emissions today

 

[ThrasherSOWT]

Question for prior and current P0446 sufferers:

Did / does your gas mileage go to crap when this code comes up?

I'm wondering if I'm seeing some effects of a larger problem, or if I'm nuts.

Thanks - T

 

[USMC_Spike]

So. If you are one to top off your fuel tank you're going to get this code. Overfilling on a 3rd gen will get fuel into the charcoal can. Don't buy a new charcoal can. Cover EVERY seam with JB weld. Install and let the code fix itself. You can plug up all ports but one on the can and induce a vacuum and see if it holds negative pressure. If it doesn't then you have cracks which you can JB weld. If it DOES hold negative pressure I'd move to checking the 2 VSVs on the can with the 9v method. This charcoal cans are super expensive for a carbon filter.

Yes, shame on me I do top off, at some pumps after it first stops I can typically add another 2 - 3 gallons of gas.

That said, Fuel into the canister, then how does one stop or reset the
code?

My driveway where I part is approx 30 slope down; I back into it so I don't
have to turn around and look in the am when leaving.

Does simply parking with a full tank on a 30 degree incline, tank down,
cause fuel to saturate the charcoal canister?

Is there another work around where the Tank Check Valve can
just be bypassed/ or plugged off? Heck they aren't in the 2002 or
later model tanks.

I've already removed the tires, getting ready to buy the parts.
Just not sure how to do the work on an incline.

 

[feta]

I just fixed on my 01 sequoia

you can read here if you are interested

https://www.tundrasolutions.com/forums/1gen-sequoia/202502-fixed-01-sequoia-gas-smell-evap/

summary: gas tank rusted and cracked by fuel pump. tank wouldn't hold pressure

 

[GetitOffroad]

lol, where is the charcoal canister? I looked on the toyota oem parts list and it refers to a vapor canister located in the driver side engine compartment...it that it?

 

[HiLife]

Yes, 2000 and earlier.
2001-02 has it near the gas tank.