sa0625

Watsup CL, so this morning on my way to work i noticed my 2001 GS300 had a check engine light on.. so i pulled over and hooked up the scanner to it and it came up with the P0446 code which is EVAP Emission Control System Vent Circuit Malfunction. What do i do and is this going to cost me a lot of cash to fix? has anyone had this issue before?

wbmx1981

I had the same problem, and mine ended up being the gas cap. The rubber gasket will wear over time. After you replace the gas cap, it will take a couple of days to reset, but the light should turn off. Another thing too is maybe the gas cap wasn't tighten all the way the last time you got gas. You can also type P0446 in the search bar to get more information. Hope this helps.

diagtime

there is a very large list of things that can cause this. it's a difficult enough problem to diagnose with the car here. it will be very hard over the internet and without the right equipment.

cruisinvip

iTrader: (2)

its the charcoal canister solenoid. Its a pain in the *** to replace but it can be done without removing the charcoal canister. Mine had a rusty valve on it.

this video also shows how to test the solenoid

sakataj

iTrader: (182)

dont assume you know whats going on, it can be many many things....without having actually put hands on the car and checking some things you dont kinow and are assuming its the charcoal solenoid. it could be bad cats, bad O2 sensors, bcracked vacuuam hoses,etc. i have been battling this code for awhile now, it comes and goes from time to time and im still chasing a few things on it

BTW your video no work, maybe its just my computer ATM but it doesnt work for me.....i will try it from a different computer as im curious to see this.

OP this quote below is 100% right

Quote:

Originally Posted by diagtime

there is a very large list of things that can cause this. it's a difficult enough problem to diagnose with the car here. it will be very hard over the internet and without the right equipment.

sa0625

sakataj you say you've been battling this code for a while now? so it is not something i need to be extremely concerned about if i cant locate the core of the problem right away? can i still drive?

neegroy

iTrader: (19)

could also be the sensor inside the system. i have one on too, just havent had time to get it looked at.

cruisinvip

iTrader: (2)

just speaking from experience. I changed out the solenoid which was 50 bucks. so i started from cheapest then up the ladder. my car has about 180k on it and all o2's and cats have never been changed. If it helps theres also ways to test this solenoid with a battery, in which i though the video would work.

If it were related the cats or the o2 then from experience, i would say he would get the po430 code.

sakataj

iTrader: (182)

oops,sorry your right, i was thinking of the wrong code....

im constantly getting a PO430 code that comes/goes

https://www.clublexus.com/forums/gs-...hat-to-do.html

diagtime

yes you can drive it. evaporative problems generally don't hurt anything except the environment.
the vapor pressure vsv is the solenoid someone else was talking about. it's one of many possible problems. could also be the vapor pressure sensor, the purge vsv stuck open, a cracked or leaking vacuum line, canister issue........tons and tons of possibilities.

cruisinvip

iTrader: (2)

yeah that one sucks too. mine is due to the gaskets after the cats leaking. ive changed it many times but i still hear a chatter and see a code. my mechanic recommended to try something stronger than the stock rubber gaskets.

sakataj

iTrader: (182)

i have all new gaskets from the motor to the B pipe, new PPE headers, all 4 new O2 sensors, hoses are not cracked/dry rotted.....i pretty much have narrowed it down to a bad cat. have some O2 foulers which will take care of it, i just haven't installed them yet. it really affects nothing and it only comes on like once every other month or so. i read it and make sure its the same code and i either clear it or i let it clear itself (which it will do in about 2 days)

diagtime

how many miles are on your car. those cats usually last a while......and aftermarket exhaust components screams exhaust leak. the most minor pinhole leak that you would never notice can cause cat codes. (depending on exactly where the leak is). if you can smoke test the exhaust system and get a small amount of pressure in there(from the rear), you can spray soap water all over the exhaust and look for bubbles.

it's certainly possible you have a bad cat. how intermittent it is goes along with that theory. but if the cause turns out to be an exhaust leak, the fouler may not fix it.

sakataj

iTrader: (182)

almost 150k....trust me no leaks up front, after installing new gaskets i used some exhaust silicon and wrapped it al the way around, havent checked after the cat as the O2 sensor wouldnt pick that up

i know how to smoke test a intake system.....how would you smoke test a exhuast system? maybe filling it with smoke from the tailpipe and pressurizing the tubing to see if its leaking?

the fouler would fix it either way, it pulls the O2 out of the "flow" so it wouldnt know the difference.

cruisinvip

iTrader: (2)

i get awful gas mileage with the po430, lack of power/response too