Good ol' P0446

OK, so I have RR the VSV solenoid and as of appox. 300 miles there has been no check engine light to come back on. I'm feeling confident the solenoid was the culprit.

Hopefully anyone in the future finds this thread as useful as I have
 
Limelight

Thanks for bringing this issue & solution back in the limelight, I don't have it but could as I'm always over-topping my tank, gotta stop doing that! Only saving grace is I drive many miles right after so it doesn't stay over-filled for very long. :banana:
 
OK :( my light has come back. I have a question concerning this, since Ive read the filler neck is associated with this code, is it possible a failing fuel pump might also be associated?

Just before the first time my code was tripped I noticed my fuel pump had gotten quite loud. It has only gotten louder, so much so that Im sure it is gonna fail soon.

Does anyone have any thoughts on this? The only thing that may makes any sense is an issue with pressure. IDK. Any input is appreciated.
 
uscfroadie said:
Hello All,

Long time lurker, first time poster.

I had the P0446 code pop up on my 2001 4 Runner Sr5 4X4 and came here to read up on the cause/fix action. I reset the code twice and had it re-appear in a short amount of time (less than 50 miles of driving), so I knew I had a problem, not a fluke. Not being one to change parts for the sake of changing, I did more research as there was no one simple cause.

I found this video - YouTube Toyota P0446 Video - that centers around the same problem, only on a Camry. The basic principle is the same, so I used this as a basis for my troubleshooting.

I removed the canister, which is a bit of a pain, at least on my 4Runner. Spare tire, 4 bolts, one electrical connector, and 6 hoses, if I remember correctly, had to be removed, and some of the connections are in really tight spaces. Still, its not difficult, just harder than it should be.

With the canister out, I performed the vacuum test specified in the video (linked above). Mine would not hold vacuum, hinting that the VCV was stuck in the open position. According to the video I needed to replace the entire canister, but being that I'm not one to top off my tank, I didn't see how the canister was bad, but I knew the valve was. Versus ordering a new canister online for $370, I opted to look for just the replacement valve, and lucky I found that it is available separately, just not from Toyota.

My local Autozone showed one for $42 and could get it within 3 hours (would be delivered from a nearby store). My dad and I ran up and looked at a print out of the piece just to be sure given that Autozone was only about two miles from my Dad's house. Yep, same part, so I ordered it. (Inserted a picture of the part below).

Three hours later the delivery truck arrived, as promised, and I was home installing the piece a few minutes later. Once again I performed the test, and it all checked out as it should - vacuum when closed; apply voltage and vacuum purges, so I (with the help of my Dad) re-installed the canister.

I reset the code and since then have put nearly 1,000 miles on the 4Runner without having the code re-appear. I even plugged in my scanner just to be sure. Yep, still no code(s), so I consider this problem fixed.

I hope this information helps someone else on this forum should they get this code on their 4 Runner.

Cheers!
Merle
Click to expand...

Completed this test tonight, same deal, bad VSV. Advance auto (Part# 911-601) has them for $46 right now so I'm going to go scoop me up one and replace it tomorrow morning. Is there another one up in the engine bay as well?
 
chrisdowling84 said:
200 miles later and still no engine light
Click to expand...

I went almost 1000 with no light and then it was it showed back up. Fuel pump is getting louder as well...I don't know if it is related, but this is a frustrating issue. mainly because I will be coming up on inspection in November.
 
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Well, I pulled my canister and sure enough the seal at the bottom is cracking away, so I caked it with gasket maker (brown) hopefully it holds up and does the trick.
 
P0446

I've given up on mine - just use Palmer to read for any new codes every month or so - then use Palmer to turn the lights off just before going to NJ inspection - works like a charm!
 
I'll jump in on the P0446 support group...

My CEL came on over a month ago: P0446. I haven't even tried diagnosing it. I've just cleared the light 4 times now with my Snap-On scan tool. (I run a body shop but it's not very often I get into diagnosing mechanical issues that involve emission-type stuff, as we don't have a smoker)

One thing I have realized though: For a long time, several years I guess, I would randomly hear something hissing and clicking from behind the dash. Possibly from the engine compartment. It would only happen occasionally and no, it didn't seem to have anything to do with the a/c or heater systems because the noise would come on even with all air systems off. When it was still happening, it would start as a slight hiss and get gradually louder until a fairly loud "Click", and then stop. I've not heard that noise again even once since my CEL has come on, so I could take a wild guess and say my code is because of whatever switch is under the hood. Which one would that be, the CCV?
 
Johnate0 said:
I'll jump in on the P0446 support group...

My CEL came on over a month ago: P0446. I haven't even tried diagnosing it. I've just cleared the light 4 times now with my Snap-On scan tool. (I run a body shop but it's not very often I get into diagnosing mechanical issues that involve emission-type stuff, as we don't have a smoker)

One thing I have realized though: For a long time, several years I guess, I would randomly hear something hissing and clicking from behind the dash. Possibly from the engine compartment. It would only happen occasionally and no, it didn't seem to have anything to do with the a/c or heater systems because the noise would come on even with all air systems off. When it was still happening, it would start as a slight hiss and get gradually louder until a fairly loud "Click", and then stop. I've not heard that noise again even once since my CEL has come on, so I could take a wild guess and say my code is because of whatever switch is under the hood. Which one would that be, the CCV?
Click to expand...

If you have a 01-02 that noise is completely normal. It actually has nothing to do with the emissions system, but rather has to do with the braking system.


http://www.toyota-4runner.org/3rd-gen-t4rs/16648-odd-noise-01-4runner.html
 
infamousRNR said:
i changed my charcoal canister and gas cap... no luck
Click to expand...

Was the canister you put in the truck new or used? Have you tested the VSV Solenoids?

Also, even though many may disagree, I swear my fuel pump was a contributor to the problem.
 
Last edited:
As I mentioned, I found that that seal around the base of the canister was deteriorating, so I used brown RTV to seal it.

So far I have traveled over 200 miles with no light, however last time I made a "fix" it went over 800. I guess we will have to see.

Here is what it looked like. As you can see I just threw caution to the wind and sealed the whole base.

 
I too had a cracked base like ajonesnv. I borrowed some roof sealant and sealed the entire bottom too. I pulled the fuse and relay for the ECU and let it all sit for a day. That was about 300 miles ago and I just passed my smog test, and I never used a code reader to clear it.
 

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ajonesnv said:
Was the canister you put in the truck new or used? Have you tested the VSV Solenoids?

Also, even though many may disagree, I swear my rule pump was a contributor to the problem.
Click to expand...

it is a new one…
how do you test the VSV solenoids?
[MENTION=113639]Mgyver1[/MENTION] where is that fuse?
 
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