So another year has gone by - and I still have the same single code, no others - and, because I haven't done anything, no resolution.
Recently, I found this paper.
http://www.ih8mud.com/tech/tsb/LexusLX450/eg002l01.pdf
My RX300 is a 2000 model, so I have a LATE model evap system.
If I read this paper correctly, the P0441 test PRECEDES the P0440 test. In my logic, that says that the pressure sensor must be working and able to see a vacuum initially. Since it fails at the next test with a P0440 rather than a P0442, there must be a BIG leak in some other part of the system. (I get ONLY P0440 code - very reliably.)
I've had the tank smoke tested, etc and have NO problems there.
With this understanding, am I correct in assuming that the canister is "bad"? Is there any other possible interpretation??
With this change, as I understand it, the system should now throw P0441 because it won't detect any vacuum.
Any help on this would be appreciated...