2003 Lexus ES 300 evap codes

My check engine light came on so I had my mechanic check the code. The code was po441 and po442 evap system.They did the smoke test and found the fuel filler neck needed to be replaced. 200 miles later it came on again same code, they explained there are numerous hoses and parts in this sytem and came up with the evap canister needed to be replaced. So after doing this and another 200 miles later, the engine light came on again. This time they replaced the vent control solenoid and again after 200 miles the light is on again. This is a local mechanic who I have been doing business with for 15 years so I trust him, but am i better off going to the dealer to get a more accurate diagnosis. This car is a 2003 Lexus es with 145,000 miles which I bought new and I have maintained well so I would like to keep it for 2 more years but I am losing patience.How many parts are left to replace?

I see a few ES300/ES330’s each year with small evaporative emission control system leaks, 95% of the time the fuel tank over-fill check valve is found to be leaking. The valve cracks and separates.

The fuel tank over-fill check valve is located on the top of the tank, the tank must be removed to replace it. If fumes are detected from the top of the tank on the right side it is very likely that the valve is leaking.


I bet a new gas cap fixed it !!!

What was the outcome??