Good ol' P0446

[ajonesnv]

There are a few VSV Solenoids, but the one that is most likely to go out is the on on the canister...

The fuse for the ECU should be in the fuse box between to the battery and the vapor canister (assuming your canister is under the hood and not under the truck), which based on the year of your truck it should be under the hood. You can get the same result by disconnecting the battery for 10min...the fuse is just far easier and convenient for a few reasons.

 

[mike_m]

evap canister

The base on my evap canister leaked at the base as well. I JB welded it and 8 months and many miles later it is still working.

 

[ajonesnv]

it is a new one…
how do you test the VSV solenoids?

[MENTION=113639]Mgyver1[/MENTION] where is that fuse?

The VSV solenoid just needs a touch of power so you can test it with leads from a 9v battery, if you hear it click when you touch the pins it is good.

So, essentially take two wires from the battery (one for each post) and tap the leads on the VSV. If it clicks it should be fine. If it is not this one there are two more that have been identified in this tread as possible culprits.

 

[infamousRNR]

if i replaced my canister then i affectively replaced the solenoids correct?

i have a 2002 so my canister is under the spare tire at the rear of the car

 

[ajonesnv]

if i replaced my canister then i affectively replaced the solenoids correct?

i have a 2002 so my canister is under the spare tire at the rear of the car

I would assume the that VSV solenoid was replaced with the canister then.

 

[Mgyver1]

Mgyver1 where is that fuse?

I pulled the relay and fuse labeled EFI in the fuse box ajonesnv mentioned.

 

[CF Medina]

Hello, sorry for bumping an old thread but I have the exact same issue and would rather not make a new thread.

My buddy who is a mechanic hooked up a Snap-On OBD II scanner and I have code P0446. No noticeable issues, fuel mileage is normal, etc. He reset the code and it didn't come up after about 200km of driving but it came up again today.

He tried turning the "EVAP VSV" on via the OBD II scanner and I got a weird repeated clicking sound (imagine a cricket) under the hood.

The sound is coming from the part labelled "VSV FOR EVAP" as shown below. Yes my 4Runner is a 96' model with the charcoal canister under the hood.

Is the repeated clicking noise in the VSV FOR EVAP solenoid the cause? My charcoal canister itself looks really clean, no visible cracks or openings.

The only issue is that I hear a weird buzzing (like a bee) coming from the canister from time to time when the truck is off.... hopefully I don't have to replace the whole canister as it's about $400 from Toyota ):

 

[ajonesnv]

Hello, sorry for bumping an old thread but I have the exact same issue and would rather not make a new thread.

My buddy who is a mechanic hooked up a Snap-On OBD II scanner and I have code P0446. No noticeable issues, fuel mileage is normal, etc. He reset the code and it didn't come up after about 200km of driving but it came up again today.

He tried turning the "EVAP VSV" on via the OBD II scanner and I got a weird repeated clicking sound (imagine a cricket) under the hood.

The sound is coming from the part labelled "VSV FOR EVAP" as shown below. Yes my 4Runner is a 96' model with the charcoal canister under the hood.

Is the repeated clicking noise in the VSV FOR EVAP solenoid the cause? My charcoal canister itself looks really clean, no visible cracks or openings.

The only issue is that I hear a weird buzzing (like a bee) coming from the canister from time to time when the truck is off.... hopefully I don't have to replace the whole canister as it's about $400 from Toyota ):

Pull the solenoid and test it with a 9v battery, if it switch it is most likely good. I found a replacement on eBay.

As far as the canister, you need to pull it and look at seam where it was pressedd and sealed. This sealant cracks and is very unnoticeable from inside the truck. Since it is out I would reseal it with something...I used roofing sealant and no problems since.

If anything these are starting points to an otherwise frustrating code.

 

[afg10000]

The buzzing bee sound is perfectly normal. I believe you should have 3 of them VSV's total. Like stated above, check all of them on a battery. If they click, they work. Did you try replacing the gas cap with a new OEM one?

 

[Blitzkrieg]

I had it on my '02 and drove me nuts.

Replaced the cap with a new Toyota cap. Everything fine for a month or two then would throw the code (especially when on highway during hot weather).

I checked everything to no avail. Finally gave up (which I rarely do) and took it into the Toyota dealer. A couple hours later the service manager called and said they figured it out.

There was one tech there that had seen it happen one time before - the charcoal canister above the gas tank had a small crack in it.

I don't remember exactly what that little canister cost, but it was not cheap. And it took like 2.5 hours of shop time checking everything.

Kudos to them, because I was at a loss as to what it might be.

 

[ajonesnv]

I had it on my '02 and drove me nuts.

Replaced the cap with a new Toyota cap. Everything fine for a month or two then would throw the code (especially when on highway during hot weather).

I checked everything to no avail. Finally gave up (which I rarely do) and took it into the Toyota dealer. A couple hours later the service manager called and said they figured it out.

There was one tech there that had seen it happen one time before - the charcoal canister above the gas tank had a small crack in it.

I don't remember exactly what that little canister cost, but it was not cheap. And it took like 2.5 hours of shop time checking everything.

Kudos to them, because I was at a loss as to what it might be.

His canister is under his hood and this cracking is typically the problem.

 

[John308]

His canister is under his hood and this cracking is typically the problem.

That was the issue on my '96. I pulled the canister, and noticed a small crack around the seam on the bottom. I bought some JB Weld epoxy made especially for plastic, and I ran a bead all around the bottom seam. I let it dry over night, and then reinstalled the canister. It's been a few months and about 1000 miles now, and I haven't thrown 446 code yet.

-John

 

[CF Medina]

Pull the solenoid and test it with a 9v battery, if it switch it is most likely good. I found a replacement on eBay.

As far as the canister, you need to pull it and look at seam where it was pressedd and sealed. This sealant cracks and is very unnoticeable from inside the truck. Since it is out I would reseal it with something...I used roofing sealant and no problems since.

If anything these are starting points to an otherwise frustrating code.

I tested the VSVs with the OBD-II scanner and the one under the hood attached to the canister clicked when power was applied. My buddy has a really nice one that has that function, but first thing tomorrow I'll test it again with the 9V.

If that works fine, I'll remove the canister and seal the bottom seams with some Permatex "flowable silicone" I have lying around. Hopefully that fixes it!

 

[MojaveMadMan]

I have read a whole bunch of threads on this subject in various places. They all seem to end up with a crack in the canister either under the hood or by the gas tank for the newer models. I would suggest that anyone give it the ol' college try with re-sealing the canister. It is about as low cost of a fix as you can get, and sometimes you can't see cracks to even know they are there. This would always be step one for me anyways...

 

[ajonesnv]

i have read a whole bunch of threads on this subject in various places. They all seem to end up with a crack in the canister either under the hood or by the gas tank for the newer models. I would suggest that anyone give it the ol' college try with re-sealing the canister. It is about as low cost of a fix as you can get, and sometimes you can't see cracks to even know they are there. This would always be step one for me anyways...

^^^^^^this^^^^^^

 

[thaemcee2]

long time lurker on this thread since I threw my first code about 6 mos. ago, and now yesterday again....I got a few questions maybe you can shed some light on...
1) at least for me, the P0446 code came on 3 times now since I bought the car in November, and each of the 3 times it came on was during or after the car sat outside in rain...what does the rain have to do with this? is it getting into the cannister? shorting the VSV solenoid?

2) I live in NJ where they do check the comp. for codes...someone on the last page of this thread from NJ said he used the palmer tool to clear the codes before inspection and he was fine...i thought they can still find codes that have been cleared?
(I dont clear the codes that way, I simply disconnect the batt)

3) after disconnecting the batt each time it came on, it would stay out for a few months until the next decent rain that it sat in...the only thing I did do was order a new OEM gas cap since it is cheap and it did look pretty bad...

I guess if this doesnt do the trick, next I will go to the VSV on the cannister...i have NJ inspection in June and do not want to start throwing boatloads of cash at a 2001 4runner with 100kmiles for a stupid code if I can get by with just clearing it before inspection...

THANKS in advance, hate to resurrect this thread!

 

[ajonesnv]

I believe the 01 canister is under the truck near the fuel tank, so it is quite possible if the canister is cracking or if the sealant on the canister is cracking water could be affecting the operation of it by inducing water to ht system.

My first stop would be to check the canister for any issues.

 

[AZBub]

I have been chasing the ole 0446 for some time now narrowed my problem down to the vcv on top of the charcoal filter. My mechanic did some sort of electrical test on all the switches on my emissions and also performed a vacuum leak test and narrowed it down (cost me a case of beer). Ordered a part from Amazon. Shows up. 2 line connections instead of 3. looked at Oreilleys. Same looking part. FML. Camelback Toyota here I come.

I'm really hating this p0446.

 

[ajonesnv]

I have been chasing the ole 0446 for some time now narrowed my problem down to the vcv on top of the charcoal filter. My mechanic did some sort of electrical test on all the switches on my emissions and also performed a vacuum leak test and narrowed it down (cost me a case of beer). Ordered a part from Amazon. Shows up. 2 line connections instead of 3. looked at Oreilleys. Same looking part. FML. Camelback Toyota here I come.

I'm really hating this p0446.

Try eBay first!

 

[AZBub]

Im about to. I can not find a match for the part I need anywhere else. And the parts diagram at Camelback Toyota doesn't look right.

Part: TOYOTA OEM 2586075140 Purger valve. ugh