I have an 02 4runner sr5 with 140k, and about 6months ago I took it to the dealership because of the CEL AND VSV lights, they told me it was the o2 sensor so I can home bought one put it in now problem, a week later all lights came back on, went advance got a P0440-p0446 code, so I went back to dealership, they said it was my gas cap and it was $76 bucks, they fixed it. 1 day later lights come back on, I go back to dealership they do a smoke test, still say its gas cap, they replaced free of charge. 1 day later back on top it back they said its still coming out the gas cap we have no idea. So they clear code, 1 day later it comes back on I have no idea what else to do please any help would be greatly appreciated, no gas smell little bit loss in gas mileage but that's it. Thanks for your help.

 

I would look into the cat. A PO440 is "catalytic convertor system efficiency below threshold" I did the same thing on my Tacoma. Replaced both O2 sensors and the light came back. I really doubt that you had a faulty gas cap at all, let alone an evaporative emissions system fault. If you do need a cat, do yourself a favor and go aftermarket (Magnaflow, Dynatech). Cheaper, better flow, and quality is as good or better than stock if you get a good brand.

 

incorrect

p0440 is an evap code

p0420 is cat below threshold

 

My bad, you're right.

 

My 2001 is also throwing out a P0440 code. Gas cap replaced but I really dont want to mess with troubleshooting. Does anyone know how to bypass the system so the CEL doesn't come on and I can pass emissions? I know that sometimes resistors can be put in place of a sensor to trick the ecu. I would like to do something like this so I never have to worry about the evap system again.