P0446 0441 and 0440 CELs
#1
Lead Lap
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I just got this happy trio of codes driving home last night (2002 SC). No other lights other than the check engine light (no VSC off, etc). As you know these are EVAP Emissions system codes related to vacuum leaks and flow conditions that can develop anywhere in the system from fuel tank to vacuum source at the engine. So -- fuel tank, charcoal cannister, vacuum lines at the engine , related solenoids/valves, and electrical related to sensing/operating the system. Just wondering what other's experiences have been so maybe I can focus on likely candidates rather than going through a full-blown diagnostic.
So far the fuel cap gasket looks good (I did spend $7 for an aftermarket replacement cap,but pretty sure that's not it. Cap wasn't loose either). The emissions line from the fuel tank that terminates at the VSV under the hood (the rubber hose that has been known to pop off it's tube - and which leads to the green cap for vacuum testing) is connected, but seems to slide easily on the tube. Wonder if it is getting brittle and is leaking just enough? Maybe I'll put on a better hose clamp. I'm going to take off the left rear wheel and see if any of the lines are off at the charcoal canister or fuel tank (known to happen, I guess). Then I'll test the vent solenoids esp the one at the canister. Canister itself would be last. I never over-ride the auto shutoff when fueling up, but don't know if the previous owners may have been mistreating the charcoal canister in this way.
We don't have emissions testing/certification in Iowa, so I'm not in a hurry (but I am going to track this down and fix). The car did pass a Texas emissions test last year.
Any other suggestions, thoughts, opinions?
So far the fuel cap gasket looks good (I did spend $7 for an aftermarket replacement cap,but pretty sure that's not it. Cap wasn't loose either). The emissions line from the fuel tank that terminates at the VSV under the hood (the rubber hose that has been known to pop off it's tube - and which leads to the green cap for vacuum testing) is connected, but seems to slide easily on the tube. Wonder if it is getting brittle and is leaking just enough? Maybe I'll put on a better hose clamp. I'm going to take off the left rear wheel and see if any of the lines are off at the charcoal canister or fuel tank (known to happen, I guess). Then I'll test the vent solenoids esp the one at the canister. Canister itself would be last. I never over-ride the auto shutoff when fueling up, but don't know if the previous owners may have been mistreating the charcoal canister in this way.
We don't have emissions testing/certification in Iowa, so I'm not in a hurry (but I am going to track this down and fix). The car did pass a Texas emissions test last year.
Any other suggestions, thoughts, opinions?
#5
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Went to the dealer the first time and spent the $80 for a read and fix (vacuum hose off). The next time it happened, I lifted the hood and searched until I fount the culprit my self. Good luck.
TOXIC
TOXIC
#6
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Suggest you reset and see what happens, if they all come back.
#7
Lead Lap
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Yes, I'm going to reset the code and see what happens.
I understand that the EVAP Emissions system has been known to easily throw codes on Toyota/Lexus since there are a lot of reasons why the pressurize/purge test of the fuel vapor evap mechanism can fail. The most frequent causes are loose/bad gas caps (it says so right on the cap!), dislodged/loose/cracked hoses (and mine on the purge line under the hood slides easily on its metal fitting like the factory clamp has no effect), and a malfunctioning vacuum switching valve at the charcoal canister. That last one is pretty high on my hit list and looks like a bugger to change - anyone done it without dropping that left axle/suspension? (Can't be worse than the steering rack I replaced on my daughter's Taurus this fall.)
I'll do things one-by-one and report back as I check things off the list.
kelly
I understand that the EVAP Emissions system has been known to easily throw codes on Toyota/Lexus since there are a lot of reasons why the pressurize/purge test of the fuel vapor evap mechanism can fail. The most frequent causes are loose/bad gas caps (it says so right on the cap!), dislodged/loose/cracked hoses (and mine on the purge line under the hood slides easily on its metal fitting like the factory clamp has no effect), and a malfunctioning vacuum switching valve at the charcoal canister. That last one is pretty high on my hit list and looks like a bugger to change - anyone done it without dropping that left axle/suspension? (Can't be worse than the steering rack I replaced on my daughter's Taurus this fall.)
I'll do things one-by-one and report back as I check things off the list.
kelly
Last edited by kjcole; 01-12-12 at 12:55 PM.
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#8
Lexus Test Driver
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Yea evap is a known issue with Toyo and lex vehicles. have reset mine by obd scanner and unplug the battery. I did have a loose hose underneath the intake box. That help a little. Longest without a code was a month and it came back. I will replace gas cap. I hope that will do it but people say probably not and I agree. I've read stories some people with evap code loose some mpg, but I don't. How about you guys? I have an is300.
#9
Lead Lap
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Maybe? When I disconnected battery ground to clear the codes, I took another look around. I found an small electrical connection on the passenger side of the engine that I didn't plug back in (a solenoid or VSV - there are vacuum lines running to it) when I was finishing the timing belt replacement. I guess I'll have to wait awhile to see if the CEL comes back on after the required number of run/stop cycles.
#10
Lead Lap
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Rats. Disconnected the battery ground for about 30 seconds, started the car. CEL still on. Maybe time to get a code reader since I have a feeling I'm going to be chasing this one for a bit. Anybody have a recommendation for a reasonably priced reader for this car?
#12
Lead Lap
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I just ordered OBDLink SX 2.0 Scan Tool to use with my laptop instead of buying a hand-held unit. Once that arrives I'll use it to clear the code. Then I can monitor for pending codes rather than just waiting to see if the code reappears. Maybe tonight I'll pull the fuse for the EFI and then replace and check in the morning, rather than disconnecting battery.
#13
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Or else go to your local BM Auto store and have them read and clear your code. Bit too late, but if you can not wait, might as well do it.
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