Codes p0440 and P0446. Fixing

So 3 weeks ago my Taco CEL went off.
Hooked my scan tool and it read P0440 and P0446. I read a bunch of threads everywhere about it. Some sugge said VSV valves which the most expensive one costs 190.00. I replaced then, erased the codes and after 3 miles the CEL went off again. I was pissed.

I tested everything and checked and replaced cracked hoses. Erased codes and CEL went off again yesterday.

After some serious research on various threads it all came down to the charcoal canister. Or so I thought. I was looking for an old friend who is a wiz at cars. I drove to his old shop and the dude wasn't there anymore. I saw another mechanic shop and just for poops and giggles asked if he had a smoke machine. I told him all the troubleshooting I did on the VSV valves and throughout the system and that everything seemed ok. After a chat he said I could use his machine. What a cool guy. He hooked it up and what do you know. Smoke was coming out of the filler kneck and a hose that goes from the canister to the gas tank.

Called the dealer and it all came down to 205.00 for the hose and filler kneck. Vs 510.00 for the canister.

Moral of the story. Perform an smoke test before throwing cash at it. I was fixing to buy the charcoal canister. Close one there.

 

Nobody likes a leaky Taco. Glad you got it fixed! I wonder what makes them crack?

 

My CEL came on with the same code p0440 what exactly did do as far as a smoke test?
Also I get an odd smell after I use my truck.

 

Glad you got it fixed without the canister. I did my canister a few years ago chasing a P0446 code. It did fix it, and I had found an OEM canister on eBay for $265. Still, a big expense.

 

Was it leaking? or was it plugged?

 

They guy hooked the machine up and smoke started coming out of various hoses. coming out of the canister. One in particular was a hose made of plastic that goes from the gas tank to the canister. It had a big hole in it.

 

That's a good question. I did not smoke test it, therefore can not be sure it was leaking. What seemed clear was that the VSV on the canister was not moving. I could not find a replacement for the VSV only, so bought the whole canister.

If I were doing the job today, I would do more testing. The service manual has the testing procedures step by step for the VSVs. I recently replaced the VSV for evap under the hood because it had stopped working and triggered the cel. All good now.

 

Hate to bring this thread back from the dead, but I am pulling p0440 and p0446 STILL after replacing the filler neck, gas cap, canister, and overfill valve. My mechanic did a smoke test and it looked like it was leaking from the gas cap and from the canister... I checked my vsv and it worked when i hooked it up to a 9V battery. What else is there that I can do to get rid of these stupid codes? Also i am getting worse milage than i usually do... if that means anything...

 

Did you use OEM parts? If those parts are still failing smoke test then... you're gonna keep getting those codes.

 

I know the gas cap is oem and the overfill check valve is, I paid a little extra for those.
the canister is this one: https://www.partsgeek.com/gbproduct...+Carbon+Canister+Dorman+911-635+02-04+Toyota]

The filler neck is this one: https://www.fillernecksupply.com/20...MIo4LdioL43wIVAxx9Ch2OEQkLEAQYASABEgJiK_D_BwE

 

Do you have cruise control?

 

Yea?

 

Is it working?
Reason I ask, is the CC works off of the vaccume lines, if there’s a leak in the hoses or any part of the systems it’ll stop working. Happened to me And that’s what led me to replace my check valve and seal.

 

Ohhh gotcha, yea its working, I just got back from a 200 mile trip and had no issues.

 

Ok just so I completely understand after you replaced the canister, gas cap, and check valve. Your still getting a leak from a smoke test or your just getting the codes?
Also when you replaced the check valve did you replace the seal?

The thing about our year is there are so many different vaccume lines it gets hard to diagnose

 

All that and the fuel filler neck. I haven't gotten it resmoked, I'm just pulling the codes.Yea I also replaced the seal and a few of the hoses that looked kinda janky.

 

Ok I’m sure you know this but when you smoke test it start from the front under the hood and work your way back, just easier to eliminate cracked hoes that way since the canister isn’t oem double check all the hoes are conncec correctly. You can’t really say what it is until you re smoke it unfortunately.

 

Yea... I think I'm gonna take it back to my smoke guy. Do you know if you have to pinch any hoses when doing the smoke test? I was watching a video on youtube and the guy used a clamp to pinch off a hose going from the canister...
Link to the video: https://www.youtube.com/watch?v=nxP4CuzV2EY

 

Ya I watch that exact video and He did that to basically to make sure smoke wasn’t escaping into the gas tank, as far as your question it’s not necessary I just disconnected the hows and held my finger over it. My hoses are old too and I didn’t want to cause a crack.

 

That makes sense. If i didn't clamp the hose, where would the smoke come out of?