P0446 EVAP/VSC Anomaly

[Brunoski]

Does any one know what the EVAP system has to do with VSC?

About 5 months ago, the engine check light went on and the VSC OFF lights went on. Checked it, and was P0446, EVAP issues. I have reset it about 4 times, with the frequency increasing. I tried diagnosing the 3 VSVs on my 02 4runer, but nothing yet. Still have to check the pressure sensor on the gas tank.

Anyways, what do the two have in common? Would there be an issue with the Skid ECU? I hate to be fixing stuff that I cant find 100% defective or to prevent from happening again.

[YotaFun]

IIRC the 01&02 4Runners would throw on the VSC light on with a check engine light.
They are not nessicarily linked however I believe those systems are disabled becuase the engine ecu figures that the VSC system can not function while there is an engine issue.

Buddy at work brought his girlfriends 01 to me with a CEL and the VSC lights on, pulled the code for a A/F sensor being bad, replaced it and reset the ecu, haven't had an issues since.

[Good Times]

When you checked the CEL codes was it just the P0446?

If so, then you're probably looking at a bad charcoal canister that needs to be replaced.

If you are also getting a few other CEL codes such as P0440/P0441/P0442 then it opens up a whole different part of the EVAP issue which could be simply a loose gas cap or improper pressure inside the fuel tank etc.

As for why the VSC lights up when the CEL does... not a clue but I suspect it's just the normal christmas tree syndrome where everything lights up so you freak out and take it into the dealer to get the repairs performed.

[corax]

P0446 Incorrect Purge Flow? Is there an air filter on the charcoal canister vent? Many vehicles have one to prevent dust / dirt from getting into the char canister - if it clogs, this light can set. Also verify that the Purge Solenoid Valve (evap solenoid that vents to the intake) is working (opens/closes fully and not restricted)

[Brunoski]

Good Times:
Yes it is always just the one code P0446. I'd really hate to replace a box with charcol for $300 or so. Is this really certainly it? I've read somehwere that you can repair the canister by "baking" it to remove the gas particles. Sounds interesting.

Corax:
I think your are refering to the VSV for CCV. I just checked it for electrical resistance and seemed normal. That is how I checked all 3 anyways.

I will have to do more research. Thanks anyways guys, you've shed more light on the situation.

[corax]

Corax:
I think your are refering to the VSV for CCV. I just checked it for electrical resistance and seemed normal. That is how I checked all 3 anyways.

I will have to do more research. Thanks anyways guys, you've shed more light on the situation.




Sounds about right (diff manufacturers, diff terminology) - it should be 2 wires, apply voltage to one and ground to the other and try to blow through it. The one that vents to the intake manifold should be normally closed (until you apply voltage) the one back by the char canister is normally open (closes w/ voltage applied). It's just a manetic coil so which terminal gets ground and which gets power shouldn't matter, you want to check actual mechanical operation of the solenoid.

[MTL_4runner]

Good Times:
Yes it is always just the one code P0446. I'd really hate to replace a box with charcol for $300 or so. Is this really certainly it? I've read somehwere that you can repair the canister by "baking" it to remove the gas particles. Sounds interesting.

Corax:
I think your are refering to the VSV for CCV. I just checked it for electrical resistance and seemed normal. That is how I checked all 3 anyways.

I will have to do more research. Thanks anyways guys, you've shed more light on the situation.




Let me save you a little work. My suggestion would with the P0446 code is to first replace the VSV closest to the EVAP cannister. If you do and the code returns, then you're going to need to replace the EVAP canister itself. Do not try and fix the one you have, once they go they are not worth trying to recondition (by baking, by drilling holes in it or by any other means). If you don't want to pay the $400 for a new one from the dealer then start hunting on www.car-part.com (http://www.car-part.com) for a boneyard near you that has one they'll ship for a decent price. Make sure it's low mileage and that they will guarantee the part. Having been burned on used parts in the past, unless it is something easily tested before install I usually just pay up for new parts. That's my $0.02 anyway.

[Brunoski]

Thanks for the info guys. I will try the path of least resistance and order the VSV for EVAP first.

Jamie, I gather that from your explanation on used parts with low mileage, there is no point of getting one even for $50 from a different year like a 96?

Many thanks again for the help guys!!!!

[MTL_4runner]

Jamie, I gather that from your explanation on used parts with low mileage, there is no point of getting one even for $50 from a different year like a 96?


You can certainly try getting one from a 2001-2002 4runner (not sure what other years that part number was good for). You'll just have to expect that you may get a dud. Then after that the junkyard won't give you your money back, but you may get stuck with an "equivalent part" of their choice (less than ideal since it may have alot more mileage on it than the first part did). Remember that in the junkyard parts game your labor time is free as far as they are concerned. Sometimes you can get lucky, but other times it can be a massive time waster and nothing but a hassle. My view is that if you value your time, juet get the best price you can on a new part and be done with it.

Here's where I get my stuff since they ship to Canada and have great prices....

VSV for EVAP:
http://www.toyotapartsales.com/partlocator/index.cfm?action=getJointLocator&siteid=214074&chapter=&Sectionids=0,2496&groupid=2497&subgroupid=10117&componentid=0&make=34&model=4Runner&year=2002&graphicID=8414710&callout=2&catalogid=2&displayCatalogid=0

Vapor Canister:
http://www.toyotapartsales.com/partlocator/index.cfm?action=getJointLocator&siteid=214074&Sectionids=0,2496&groupid=2497&subgroupid=2500&componentid=&make=34&model=4Runner&year=2002&graphicID=8414710&callout=1&catalogid=2&displayCatalogid=0

I'd probably just get the VSV at your local dealer to save time and then get the EVAP canister from them if the VSV doesn't do the job for you.

[MTL_4runner]

Found this TSB (EG003–98) from Toyota, but it essentially says the same thing I did above.

http://www.toyotapart.com/EVAP_SYSTEM_DIAGNOSIS_P0441_P0446_T-EG003-98.pdf