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Ron Z.
Ron Z., - Toyota Tech -
Category: Toyota
Satisfied Customers: 18773
Experience:  18+yrs experience. State Inspector and Toyota Diagnostics
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corolla: I am getting the code P0446 which deals with the evaporative

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I am getting the code P0446 which deals with the evaporative systrem. What is the most likely cause for the code. I checked the gas cap and it is good.
Hello! Welcome to the site! Thanks for coming! I'm Ron Z. I'm here to provide as much info and insight as I can, to best answer your question.

The P0446 is a difficult one to diagnose, as there are a few different things that can set this code. The P0446 is recorded by the ECM when there is an evaporative emissions leak from the components within the EVAP System, or when there is a malfunction in either the VSV for EVAP, the VSV for vapor pressure sensor, or in the vapor pressure sensor itself. So, best place to start here is with a EVAP Smoke Test. This is where a machine forces smoke through the system and any leaks will reveal themselves. If the smoke test shows no leaks, then unfortunately, the items above will need to be tested for proper operation. More times that not, it's one of the VSV's as they have a fairly high fail rate, so this would be the best place to start.

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