Toyota is having a lot of problems with failures in their EVAP systems. The most common code P0446 pertains to the vent solenoid. This is the solenoid that opens to allow air into the charcoal canister during a purge cycle. The solenoid is normally closed. When it is energized it opens and allows air in. If it sticks open, the pressure sensor on the charcoal canister won’t see an increase in vacuum and will set code P0446. However, there are two solenoid valves; 1) the vacuum switching valve VSV closed valve (normally closed) and the 2) canister closed (VSV) valve (normally open). The canister closed valve is located on the air intake.

Test the solenoids by applying vacuum from a hand-held pump. If the valve is normally closed, it should hold vacuum. Apply 12volts and ground to the terminals and see if it opens. Then remove the voltage and apply the vacuum again. Do the same testing procedure for the canister closed valve with opposite results.

If the solenoids don’t work properly, replace them with new ones from Toyota.

Click here and enter your vehicle specs to find a replacement purge solenoid

For more information on this repair or any others for your vehicle, buy an online subscription to either Alldatadiy.com or eautorepair.net. Click on this link to compare the two services: Compare Alldata and Eautorepair.

If you just need information for a single repair and want to save money,eautorepair offers a lower price 1-week subscription for only $11.99. Or, if you’ll be working on this vehicle in the future, you can buy a 1-year subscription (Alldatadiy.com for $26.99, or eautorepair.net $29.99)

© 2012 Rick Muscoplat

Alldata and Eautorepair are both professional grade shop manuals. You’ll find more in-depth information and more complete wiring diagrams, along with descriptions of how the systems work. And, you’ll get all that at a price you can afford. Check them out!

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