2000 RX300 Gen 1

Only the 440 code shows up, oddly.

What I have done over the last month...in order...
Purchased a new Gas cap.
Replaced every vacuum hose in the engine compartment (followed the diagram) and added clamps where I thought prudent
Replaced the hoses from the hard lines in the body to the charcoal cannister (clamps added here too)
Replaced all of the VSVs (4 in the engine compartment)
Purchased another Gas Cap
Replaced the charcoal cannister with the recommended one (by date of vehicle manufacture).

Each step followed by a code reset, and still the code pops back up within 40 miles.

Reading earlier posts I would mention that there is no "hissing" sound heard when the gas cap is removed. (must be a gross leak)

There is no No gas smell that I can tell. (possible Cracked overfill check valve)


Any other ideas that I might try out?

I guess a smoke test is in order but I sure thought I could solve this thing by the course I've shown.

Thanks for any replies

 

I am with your conclusion. Visit a mechanic who has "smoke machine" and locate the source of leak.
I don't blame you for trying to do simple things but we all know that it is hit or miss. Talking about simple fixes, check the hose at the back of the air filter box. Specially if the CEL was triggered after the air box was moved around. I would have opted for the smoke machine before replacing the charcoal filter [that is no fun].

When you look back at the time and money spent, using the proper equipment to diagnose is the right way.

Salim