PO 0446 and I need to smog the truck soon.

[StreetCreeper]

I recently had a CEL come on and it was PO 0446 Evap control system vent circuit malfunction if I remember correctly. I cleared the code and it stayed off for about a week, then came back.

The code stayed on for about 4 days or so and then turned off on its own. I'm sure it will come back again in a few days.

Since my CEL has been coming on and it's regarding the emissions stuff, naturally I get my letter from the DMV telling me it's time to renew my registration and to get it smogged first.

I'll go through and figure out what the problem is eventually, but I'd rather do it when I have both the time and money to mess with it.

My question is if I can simply wait until the light is off for a few days and then get it smogged, or will they be able to see the code still?

 

[AZBub]

Not sure about the codes but look at the cheapest possible fix first. check the vapor can for cracks....even hairline cracks. Buy some JB weld and seal the seam all the way around and the cracks if present. Could be that's simple. Mine would come and go as well until I did that.

With my luck the light would turn on on my drive to DMV. How is your luck?

 

[SST221]

I would check you purge valve, your EVAP monitor will not be passed and with a check engine light its an automatic failure. Really not that hard to check. Google it. If there are no other codes such as "lean condition" or "Fuel trim" then most likely its just not opening to allow flow from canister to intake which is measured by a pressure sensor and monitoring fuel trims. Basically.

 

[ajonesnv]

There are a couple common things...like stated above reseal the canister. Then do a voltage check on the VSV solenoids on the canister. Check all your vacuum lines for leaks. Chances are the canister's seam is cracking and falling out. Id start there.

Also, I have a similar issue with mine and even though I'd get a CEL sometimes other times the computer was running clear. All monitors functioning with no pending or thrown codes.

Might be worth your while to get a scan gauge or a wifi OBII reader with Dash Commander for iPhone or android.

 

[afg10000]

Try a new OEM gas cap first. As stated above, check the VSV's. I bet ya one of them seized up.

 

[jgue467]

...
My question is if I can simply wait until the light is off for a few days and then get it smogged, or will they be able to see the code still?

Well when the code is erased, its erased but that part of the smog system will say 'Not Ready' - different parts of the system have different parameters allowing it to change to 'Ready' (could be # of miles, # of starts, etc.).

Not sure about Cali but Tejas allows any 1 part of the smog system to be in that state and still Pass, so here as long as all the other parts say 'Ready' it would pass. I'm sure you want to fix it anyway but perhaps check what Cali allows and you'll know how soon you have to or not get it repaired. Luck! :cowboy:

 

[ajonesnv]

A lot of good info in here: http://www.toyota-4runner.org/3rd-gen-t4rs/53593-good-ol-p0446.html

 

[JBurt]

I tried lots of stuff and it was a cracked canister. One seam had just barely started to come apart. I think I've got a pic somewhere...

 

[StreetCreeper]

Not sure about the codes but look at the cheapest possible fix first. check the vapor can for cracks....even hairline cracks. Buy some JB weld and seal the seam all the way around and the cracks if present. Could be that's simple. Mine would come and go as well until I did that.

With my luck the light would turn on on my drive to DMV. How is your luck?

My luck is the same as yours!

Originally I wasn't going to start with the fuel cap, because from my initial reading, the fuel cap was not often the culprit. However, twice now I've had the CEL come on directly after getting fuel. I usually just throw a $20 in, so over-filling it isn't likely the cause. Maybe it actually is the gas cap...if only my luck were that good!

I would check you purge valve, your EVAP monitor will not be passed and with a check engine light its an automatic failure. Really not that hard to check. Google it. If there are no other codes such as "lean condition" or "Fuel trim" then most likely its just not opening to allow flow from canister to intake which is measured by a pressure sensor and monitoring fuel trims. Basically.

I'll start simple and work from there up! I didn't see any other codes, but I've not checked again since I cleared it the first time. I just assumed it was the same code popping up, but I guess there is a chance that it's throwing new codes now. I'll check again.

There are a couple common things...like stated above reseal the canister. Then do a voltage check on the VSV solenoids on the canister. Check all your vacuum lines for leaks. Chances are the canister's seam is cracking and falling out. Id start there.

Also, I have a similar issue with mine and even though I'd get a CEL sometimes other times the computer was running clear. All monitors functioning with no pending or thrown codes.

Might be worth your while to get a scan gauge or a wifi OBII reader with Dash Commander for iPhone or android.

I'll be checking the switches with the 9v battery tester I read about in another thread. I definetly need to get some type of monitor though. Just wish the Scan Gauge read tranny temps for 97s...kinda makes it hard to justify the cost since they can't read that crucial info.

Try a new OEM gas cap first. As stated above, check the VSV's. I bet ya one of them seized up.

you may be right! I wasn't going to throw parts at it originally...but after noticing the CEL come on again today moments after filling up — I'll entertain the remote possibility that the solution could be that simple.

Well when the code is erased, its erased but that part of the smog system will say 'Not Ready' - different parts of the system have different parameters allowing it to change to 'Ready' (could be # of miles, # of starts, etc.).

Not sure about Cali but Tejas allows any 1 part of the smog system to be in that state and still Pass, so here as long as all the other parts say 'Ready' it would pass. I'm sure you want to fix it anyway but perhaps check what Cali allows and you'll know how soon you have to or not get it repaired. Luck! :cowboy:

That's good info to know, I'll have to do some digging to see what Calif smog laws say.

A lot of good info in here: http://www.toyota-4runner.org/3rd-gen-t4rs/53593-good-ol-p0446.html

Thanks for the link, just read it — good stuff.

I tried lots of stuff and it was a cracked canister. One seam had just barely started to come apart. I think I've got a pic somewhere...

Looks like taking the canister out is pretty straightforward. That's usually my cue to be extra cautious...it's always when I think it will be a breeze that I F-something up! :biggrin1:

 

[osphewr]

I think I've got a pic somewhere.

 

[thaemcee2]

I had this a few weeks before my state inspection was due...new gas cap didnt do it..had no cracks either, turned out to be a bad VSV on the canister itself..try not to just start blindly throwing money at it, check it for cracks/leaks if you can first, then check all the valves on the unit itself...I had a bud who works at a local meineke do a smoke test but determined it was the VSV..all for 60$ CEL went away and has been off for 4 months now