Lmilhorn11

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.

nitrowrench79

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.

BigBallsMcFalls

incorrect

p0440 is an evap code

p0420 is cat below threshold

nitrowrench79

My bad, you're right.

skysailor68

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.