I have a 1998 Camry with 135K miles. The stupid check engine light has been off and on for years with the intermittent P0046 code (once for an oxygen sensor). I never top off the tank and have replaced the gas cap. The latest nightmare began about a year ago. After having the light on for several months, I took it in and paid ~$200 to have a broken vacuum line fixed and hopefully fix the P0046 code. Unfortunately two weeks later the light came back on. I took it back to the mechanic who said that the vacuum line break didn’t fix the code and now I will need to replace the canister and the solenoid valve to the tune of $600. Is this necessary/ridiculous??? Can I do it myself?? Should I just put electrical tape over the light and forget about it?
Sorry…code is P0446.
He’s guessing. There’s no way he should be replacing the canister AND the “valve” at the same time without doing the proper diagnostic tests. This is one instance where a Toyota dealer mechanic is more likely to have the correct diagnostic procedures and the right tools to diagnose the problem properly, the first time. If you’re already using a dealer mechanic, find a different dealership…
It’s been my experience that most matters related to the check engine light are best left to a dealership. They can also tell you of any adverse effects if you do not have the problem repaired, and can usually give an exact dollar amount for the fix.
P0446…Evaporative Emission Control System Vent Control Circuit
Basically, there is a problem in the Evaporative Control System that minimizes the about of gasoline vapor that escapes from your gasoline tank. Unfortunately, it seems to be a common problem on Camrys. My guess is that there may not be a lot of margin between working right and not working right.
What I’d suggest is spending an evening with your favorite search engine researching what causes the code and how to fix it. Be sure and check this link http://www.automotiveforums.com/t248149.html which sounds pretty plausible.
Can you fix it yourself? Strictly speaking, you can fix virtually any automobile problem yourself with enough time, patience, equipment, research, and perseverance. I suspect that if the problem is the cannister control valve, you can probably fix it yourself if you aren’t a total klutz. Fixing the tank bypass valve might be a bit more challenging but still probably possible. If it is something else, you might need to go to a (different) mechanic. FWIW, I have found our 1999 Camry to be a bear to work on because of parts are generally not positioned with replacement in mind.
Can you just ignore the problem? You can of course. And you very well might get away with it. But if you decide to do that, you might wish to buy a code scanner and check every day or so for codes other than P0446.
The connection between PO446 (vent valve performance) and 02 sensor is that it will not set if a H02S code is present,at least thats how I read what I have.
A plugged,kinked,pinched hose will also set this code,so will electrical connections to the vent valve.
Why does he want to do both the valve and the canister at the same time? He must test the valve and all else before he goes to the canister which is a ways down the list.
You guys might try checking the link in the posts. I’m sure that the original poster will read it. It explains how to test both valves and lays out a rough diagnostic procedure including the dealer for tough problems. I’m pretty sure that’s what the guy is looking for, not “take it to an expert” which is what he has done with nothing but frustration to show for it.
The guy won’t want to change both. He’ll read the link and test both, then maybe try to fix one if it turns out to be failing. Assuming that he can even find the valves which I suspect may not be all that easy if he has no idea what under the hood is what.
I expect that it’s not a hose, but only because he’s had this looked at several times. And of course the last guy who worked on it may have fixed only one problem, or might have installed a new problem.
O2 sensor codes won’t set if there is a evaporative control system problem? Seems weird, but all things are possible I suppose. You have any idea why not? I can’t think why. I think he just mentioned the O2 sensor because he got a P013x-P014x or similar code once. Every other time – an exasperating number of times apparently – the code has been P0446. At least that’s what I think he’s saying.
The other way around P0446 wont set if there is a 02 sensor code,from a generic OBD2 text book.
Do you feel in a DIY frame of mind? Here are the photographs on “how to replace the VSV valve”: http://www.automotiveforums.com/vbulletin/showthread.php?t=729289&highlight=diy+p0446 (scroll down for pics).
I’ve already perused the on-line description of the problem as well as a half dozen responses to people with the same problem, some of them on Toyota boards. If someone can’t manage a simple google search, I have little hope that they can fix the problem themselves. The only reason I opened this post was because I have some experience fixing these type of emission problems on my own Toyota Camry and thought it might be something I could help out on. After reviewing the potential causes, the troubleshooting procedure (specific to this vehicle) and all things considered, I chose to post the suggestion I gave above.
This person does not have any repair manuals and likely only has rudimentary tools. Are you going to hold their hand through what will likely be a very difficult process of describing not only where to look but how to do the testing? My hat’s off to you. My experience has been that many of the OPs never even return after their intial query. When they do, very few have the actual skills or tools to do the work.
OP’s frustrated? More than likely. It is obvious that the “mechanic” who did the original “work” and is now suggesting replacing some expensive components that normally would never be replaced as a pair unless there was definitive diagnostic evidence that they both had indeed failed, is guessing at the owner’s expense. This person is not an expert in my opinion and a mistake was made to entrust them with this type of problem. Clearly, seeing someone that is likely to have more experience in this area is warranted. Lesson learned, perhaps. If you had a brain injury and went to see a general practitioner for surgery and were dissatisfied at the results, would you give up and try to do the work yourself 
TwinTurbo thinks that we, responders, may be giving advice and instructions the poster can’t handle. That may be; but, people can learn, and, there are other people who read the posts who may apply the advice and benefit, either today, or tomorrow. It would be nice if those people would speak up, sometime.
I understand TwinTurbo’s position; we really need more feedback, and “feedforward” from more people, to be most effective, and feel that we’re not just wasting our time…
I’ve been visiting this site on and off almost since its inception. I used to invest quite a bit of time posting detailed responses to queries on this board only to have the OP either never respond or to find out they were really looking for the easy answer to their problem. The occasional DIYer that would engage in discussion and provide feedback was rare and made it all worthwhile. But I learned that it was better to see if they would even respond before investing a lot of effort. I like the “bench racing” banter amongst the regulars too but the satisfaction of helping someone fix their own problem is far more rewarding.
We get so little information to go on most of the time and so I think its human nature to fill in the blanks from our own, unique perspectives. When I read the original post, I see someone who is asking these questions;
Am I being ripped off?
Does the mechanic have a clue?
If not, can I fix it myself?
Can I safely ignore the problem?
They’re obviously frustrated that it’s been going on for so long, costing so much and still not resolved. My perception of the post is that the question, can I do this myself? is more of a last resort than a desire to actually perform the work. Bearing in mind, this person originally went to see a “professional” to get it fixed.
I’ve fixed enough emissions related problems to know- you must at least have an OBDII scanner to be effective or you’ll be waiting a l-o-n-g time to know if you’ve actually fixed the problem if you’re working with just a MIL for an indicator.
I reviewed the code and troubleshooting chart. Not exactly noob material IMHO.
The current “mechanic” doesn’t seem to have a clue. Doesn’t sound like a dealer mech to me. I know someone with the right tools and knowledge can nail this pretty quick. So, my advice- take it in to the right people and be done with it.
You make a good point about the discussion maybe being beneficial to someone in the future. I’m not knocking the discussion aspect, just responding to someone who insinuated that I hadn’t given it any thought and was merely pointing the OP back along the same path of frustration they had come here from.
Some of the 1998 Camrys (manufactured before Feb 24/25 or so of 98) are covered by an Toyota extended warranty on the evaporative emissions systems; some other Toyotas of this vintage are covered as well. This extended warranty is good for 14 years or 150,000 miles. The extended warranty is a response to a settlement between the Environmental Protection Agency and Toyota. See this website: http://www.epa.gov/oecaerth/resources/cases/civil/caa/toyota.html. If you qualify based on the documents they have here, contact your dealer. I have a 98 Camry with the same code and a need for a replacement charcoal canister but Toyota initially said it did not qualify because the VIN numbers weren’t right. You should be covered as long as you fall into the categories listed. I have been dealing with this the past few days and Toyota initially said no, but then have said they were mistaken and will cover the repairs. Good luck!