P0441 & P0455 after 250+ miles after replacing 02 sensor

I haven't even looked up these two codes but you replaced one O2 sensor there are two and they are kind of a set The computer reads the upstream and the downstream matches the voltage reading it's getting and makes an adjustment accordingly maybe the one that's not been replaced is past due and then everything may go to working if you replace your gas cap with a Toyota approved unit I would think your gas cap would be in good shape maybe you saved your old one and you could put it back on to run a test and see that would kind of be a way of figuring this out.

 

Those codes are evaporative emission codes, are they not? So unlikely anything to do with either O2 sensor methinks.

 

Then you'll have to try and find sub codes if there's such a thing for this You're evaporative system on these cars is pretty wild there's a green fitting where you can blow smoke and do all that kind of nonsense but if there's anything like my sienna and Corolla there is an EVAP switch near the canister that constantly or regularly goes bad and this is what sets the light in my sienna van right regularly because this solenoid goes bad The minute I unplug and change the solenoid the light goes away without even resetting the codes or resetting the system my Corolla has a similar valve it opens and allows gas to go from the charcoal canister to be rebreathed by the engine or something along those lines.

 

Yes see that green fitting up under the car that green cap on that plastic tube whatever you should have that That's the checkpoint where you can blow gas smoke whatever through there and the gist of it is it will come out where it's not supposed to and then either a solenoid or a gas cap or what have you or a one-way type valve is not functioning this is very common in my Toyota sienna when the light comes on there's nothing else I check I go back by the gas tank and look at the solenoid and it's not working replace it the light goes off. This code will probably be similar there's a solenoid or something that's not allowing the EVAP system to draw the stuff from the canister or put the stuff into the canister or something along those lines not really heavy duty stuff here. More of a p i t a

 

All 3 codes have to do with the evapprative emissions system ( gasoline vapors from the fuel tank). Yes the gas cap can cause codes. I see enough problems with aftermarket replacement caps that I only use genuine OE (Toyota) cap.

There are many parts in the evap system that can be the source of your problem. If the codes return after getting an OE cap then you likely will have to have a shop test the system- all the solenoid valves, the system pressure sensor, the leak detection pump, all the hoses and lines, and the tank itself.

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