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Discussion Starter #1 (Edited)
Hey guys my car is throwing some codes and I need your help. I previously had headers on the car, and o2 sim, but i thought the o2 simulator was faulty and never really gave too much thought about it. I have reverted back to all stock though.

Here are the codes: P0441, P0442, P0446

I saw the following threads via search:

http://my.is/forums/f115/just-fixed-still-cel-336501/

http://my.is/forums/f115/check-engine-light-326573/

but i dont think those are the issue, anybody help me out or tell me what to look for? thanks a bunch! Also can anybody tell me how much lexus would charge/diagnose if I do need to take it in. Car is 03', so its out of warranty.

BIG IMAGES on engine bay:




John
 

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P0441: Evaporative emission control system incorrect purge flow.
P0446: Evaporative emission control systen vent control malfunction.
Both put out the same troubled area to check;
Check vacuum hoses see if they are cracked, holed, blocked, damage or disconnected.
Check for open or short in the vapor pressure sensor circuit.
Vapor pressure sensor no good.
Check for open or short in VSV circuit for evap.
VSV for evap no good.
Check for open or shortin VSV circuit for vapor pressure sensor.
VSV for vapor pressure sensor no good.
Check charcoal canister for damage.
Check fuel tank over fill check valve for damage.
Check ECM.
You will get these 2 codes because the ECM has detected an abnormality in the evaporative emission control system. This is recorded by the ECM when there is a leak from the vapor pressure sensor, vsv for canister close valve, and vsv for presure switching valve.
Not sure about your other code P0442
 

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your having the most common problems with these cars. the evap system. off the top of my head its a evap malf, evap small leak and a evap vent control malf.
the vsv lambchop11078 is talking about is the ccv i think its proper name is close canister valve. its the valve that lets the vapor pressure from the charcoal canister back into the intake to be burned instead of being vented into the atmosphere.
if you had those hose not hooked or unplug it will set a code. also if you have your gas cap loose you can get codes like that. id hook everything up right and clear the code again and wait for your evap monitors to run again and hopefully you'll be good.
the dealer will most likely charge you and hour diag to pull the codes and do a visual check of the system. if there "leak" codes they might want to run a evap leak check which might be more.
any more questions just ask.
skot
 

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Discussion Starter #6
i've been throwing these codes for a while, this is already been reset so many times.
 

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yeah then you need to get the evap system checked out.
this is my process when working this issue...

i check for a loose gas cap.
then i pressure test the gas cap. if thats good then i run the evap system check on our scan tool.
with that you will most likely see the issue. that tool is like 9 grand so it will be hard to find one outside the dealer. but if everything is hooked up right and your cap is good thats really the only way to find out for sure. for fun it you have a friend with an lexus with a similar gas cap to try swaping them out so see if its your cap; if you cant test it.
 
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