Benjamin T

iTrader: (2)

99 gs400. almost 100k mi, and going home i got this yesterday:

P0446
EVAP Emission Control System Vent Control Malfunction

tightening the gas cap did not help. mechanic i went to says replacing it probably will not work either. i did get the TB cleaned out a few weeks back so some vacuum lines were disconnected when removing the air cleaner setup but i've checked any everything seems fine.

i called the dealer and they want $1100 to replace the charcoal canister, which unforunately is buried behind the exhaust plumbing and rear differential, meaning a 3 hour job according to the book (probably designed by the same engineer who located the starter). the mechanic i originally went to said he could do it for much cheaper if i could get the canister myself, but as expected the dealer will not help with part numbers.

i know a lot of people have suffered this mishap before, and i'm hoping they still have the part number for the charcoal canister in their records... can you please give me the number? i am suspicious again that it might be a toyota part that i can get much cheaper from a toyota parts dept. rather than lexus (20% more retail here).

any help is appreciated

Lexus GS3

iTrader: (2)

Is the Charcoal canister.. My buddy car had the same code and he replaced the charcoal canister and problem solved. He bought the part for 560 and pay 100 dollar labor.

DjFergi

I just rec'd this error code as well. I rec'd p0441 and p0446. I had auto zone check the codes. I also had them clear them out. I drove around for the rest of the week with no check engine light. I stopped to fill my car up with gas and the second I took the gas cap off the check engine light came on. This leads me to believe that the gas cap is faulty.

Anyone have any more input?

KiPod

iTrader: (31)

PN 77740-30311. Im dealing with a P0446 also. I did an evap pressure test toward the canister and it came back fine. The techs said if the canister holds pressure its fine. I tested the prussure toward the valve and it wasnt holding, so I swapped the valve. The code came back. There have been a couple GSs that have needed to have the ECU swapped to solve the problem. Im hoping I dont need to do that but I spoke to 4 different people who have had the same problem. Swapped canisters, valves, gas caps, etc. It always came back with the same code P0446. They called Lexus who said to replace the ECU. Then its fixed. Apparently, this has only happened to early 98 GSs.... so far. But seems there are a couple of us dealing with this code right now.

DjFergi

I took a ride down to my local lexus dealer and bought a gas cap. It was only 30 bucks. I swapped the cap out and unplugged the battery. I turned the car back on and the check engine light was off. I took the gas cap off while the car was running and the light stayed off. So i think my issue is fixed. I'll have to drive a little to make sure.

KiPod

iTrader: (31)

If the light is off whether the cap is on or off, then the light has nothing to do with the cap.

tam4G63

iTrader: (1)

Unplugging your battery is the wrong way to reset a Engine/Service engine soon light. By doing so your actually reseting the memory in the computer and it requires a drive cycle up to about 50 miles plus to recalibrate the moniters/ readings on the pcm. So give it some time, if the problem is still there the light will come back on when the pcm is done running its moniters.

Example, new smog II machine, customer brings in a car for a smog inspection, new law requires all obII vehicle to have the harness plug in to do a pcm reading. There's no engine light on, runs smog, car fails for MIL (engine light). Turns out customer just replace the battery earlier in the day or so.

It needs to trip the pcm atleast three times, and if the problem is still there it will come back, takes time and a drive cycle to find out.

tam4G63

iTrader: (1)

First step is you have to perform a evap leak test. Its a smoke machine that sends smoke throught the evap system and if there is a leak, you will see the smoke coming from where ever its leaking, canister, vapor solenoid, gas tank, gas cap fucntion test, vacum hoses and etc.

DjFergi

I agree with you, however I had advanced clear the previous check engine light when it first came on. I then drove more than 50 miles and the light never came back on. As soon as I went to fill my tank the light came on which led me to believe that it is gas cap related. Either way, I'll have to just drive around for alittle to see if the issue happens again.

DjFergi

It might have been a coincidence, but that is when I noticed that the light came back on. As soon as I took the gas cap off is when the light came on. I guess time will tell.

bruceko

It might be worth a try checking Tsb for it.
I had a 99 that had the same problem starting about 4 month after I bought it new. Lexus knew they had a problem with that and after 5 failed attempts at repairing it I filed under the lemon law. I had a 45 day waiting period before the state would look at it and on day 44 lexus finally bought the car back.

UberNoob

ben, which dealer is it that wouldnt help u with the parts number?

btw u might want to try cleaning the gas cap threads/ o-ring seal
maybe there is something there preventing it from getting a good seal
or maybe u filled up too much gas?

were u working on ur car b4 this?
maybe u left out a vacuum hose?

FlavesLex

iTrader: (1)

BUMP... Just got this darn code P0446 I filled up with gas yesterday but didn't even think of checking the fuel cap today. Disconnected battery and will reconnect tomorrow. I'll post back with results sometime this week. Wish me luck dudes and dudettes .

DjFergi

I rec'd the p0441 and p0446. I replaced the gas cap and cleared the codes. I drove the car for for over 50 miles and the light came back on. I had the codes read again. I only rec'd the p0446. The new gas cap fixed the p0441 trouble code.

As far as the p0446, i did some research on the NET. I found an article form the EPA labeled the Clean Air Act. In this article it listed a lawsuit which Toyota settled in regards to the charcoal canister going bad. This issue affected al Toyota vechiles manufactured between 1996 and 1998. Due to the settlement reached by Toyota, Toyota extended the normal emissions warranty to 14 years or 150k miles.

I'm going to speak with my service manager at my local dealer to see if he knows anything about this extension on the warranty.

JacobT

I had the same issue 2 years ago. I did my research and found out the Clean Air Act you talked about. I brought this up to Lexus HQ and found out the Toyota 14 year/ 150k miles emission warranty only covers state of California due to their strict emission laws.

I ended up bite the bullet and bought the charcoal canister from Carson Toyota for $400 and $200 labor from a local shop. I eliminated the P0446 code and had no problem since then