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I've been trying to find a solution to this and I still haven't been able to do it. I've replaced the canister, gas cap, and checked all lines including air filter hoses. I am posting some pics in hopes that I may not be noticing something in the engine bay area. I just noticed one more possible thing that could be the issue, the green cap that you can see in this picture was previously open and I screwed it shut but I haven't rode around enough to see if it will clear the codes. I should ask should that green cap be closed shut by screwing it home or should it be open like it was? I am hoping that if was supposed to be closed shut i've maybe resolved my issue, then again i've thought many times that the issue was resolved by doing the other things I did.
I suggest checking the rubber vacuum lines in the evaporative system under the rear of the car, driver side. Those hoses rot with age and can cause several CEL codes.
As an additional note I also have an 01 GS300 and everytime i remove the gas cap i can hear a swoosh noice which means that the fuel tank has a greater pressure than atmosphere thus not throwing CEL on the GS. The RX doesnt do this when i remove gas cap.
I replaced the canister after all instead of just the vsv. I am now trying to experiment with utilizing the gas cap from the GS 300 (no CEL lights on) that I have to at least narrow down that its not the gas cap. The one I bought for the Rx 300 was from on online dealer through ebay, so it could have been not to OEM specs even though it said it was. The mechanic I took it to said they smoked tested it and that only the vsv on the canister was bad they recommended to replace the whole canister but they wanted 700 for the jobs so I just did it myself. So here I am back to square one only $500 bucks poorer, hopefully it ends up being the gas cap.
You can definitely replace the vsv without having to replace the canister on an 01 rx which i did initially but that didnt work as it still was throwing CEL. So I decided to just replace the whole canister as the mechanic recommended, that hasnt solved it either.
Have you tested the VSV's in the engine compartment?
When I had this issue I vacuum tested all the hoses and VSV's in the engine compartment, and tested the VSVs by energizing them. The canister failed the canister diagnostic.
After I replaced it my codes did not return.
Just going to take it to Lexus dealership here in Austin, Texas. I tried to fix this issue myself but i'd rather put it on the dealership to assess, I know what i've done so I won't let them do unnecessary fixes as i've replaced all the expensive stuff myself already.
So I dropped the RX 300 off at the dealership today just got a call back stating that the rollover valve needed to be replaced on the gas tank. They want a little over $600 to do the job because they have to drop the tank. I wanted to see if you all could provide your opinions of how likely the diagnosis is of the issue being the roll over valve. Hopefully I hear back from someone more knowledgeable than myself on this forum by tomorrow when I speak to the mechanic so that I could make the best decision on whether this will likely fix the P0440 and P0442 codes. Like mentioned previously i've already addressed the typical areas that are cheaper solutions.
hard to imagine that component would fail but I guess it does. I suppose its a fair assessment from the Lexus dealership. If it doesn't fix the issue I guess I could leverage the fact that I paid $600 for a repair and still no solution to P0440 & P0442.
09-12-16, 01:33 PM
P0440 & p0442 cel
