Originally Posted by PenQuin

I'm showing codes P0440, P0441, P0446 all somewhat related to this thread but I'm having some trouble. A good friend of mine says my issue is a bad purge control solinoid valve... hsould I also check these vaccumm lines like the beginning of this post?

Originally Posted by Brewmyown

It's either a leak in the Evap system or possibly the Evap canister. You already replaced one of the possible valves. Take a look at the Evap system component layout and check any of the lines or components.

Originally Posted by Brewmyown

First thing I would do is buy an OEM gas cap from the Lexus dealer for about $15-$20 to replace the one you have. Do not buy an aftermarket gas cap. It's the cheapest place to start and it fixes those codes more times than not. Besides, If it doesn't fix it you likely need a new one anyway. Another place to look is for a leak in the system. The most common place is under the hood on the drivers side of the motor. Take a 10mm socket, unscrew the two nuts holding the engine cover down. Pop off the cover and look right near the oil fill tube and you'll see some vacuum lines entering a valve looking part and I believe there's a green cap in the location. Some times there is a hose that just falls off and people just slip it back on and its good to go. In my case, the lines where just very loose. Replacing the gas cap and putting hose clamps on those 2 or 3 lines solved my issue which you are having. If your scanner wont clear the lights and codes you can always disconnect the negative battery cable for a while then reconnect. You need to reset all your settings in doing so. I think there may be a fuse you could yank but maybe someone else will chime in on that one. To me its no big deal to reset things if I ever need to.

Initially the code would come and go. Then one day on my way to the airport to pick up my daughter, the VSC lights came on. I researched possible causes while on that short jaunt and stopped at a Lexus dealer on my way home to buy the cap. I did what I described above and its probably been a year and at least 25,000 miles (cant remember exactly) and all is well.

Good luck and let us know what you find.