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P0446 code is set off when the computer of your vehicle's engine detects a restriction or a problem at the vent control portion of the Evaporative (EVAP) Emission Control System.
The exact description of the issue differs from one car model to the other, so you'll need to do some testing to pinpoint the defective component. Continue reading to find out more about the code P0446.
P0446 is a diagnostic trouble code (DTC) which is a generic OBD2 powertrain code. It applies to all vehicles manufactured since 1996, but some models will require additional or specific steps for repairing.
The code P0446 is triggered by the engine computer (ECU) when there's a malfunction in the EVAP control system vent control valve.
The Evaporative (EVAP) Emission Control System is one of the methods your engine uses to limit its harmful emissions. It prevents the escape of fuel vapors from the fuel tank to the atmosphere.
These vapors are trapped in the charcoal canister where they get absorbed into small pellets made of activated charcoal.
There are 2 main
Normally when the engine is running, the vent control valve is open while the purge volume control valve is closed. When the ECM is ready to expel the fuel vapors, it opens the purge valve to burn the stored vapors from the charcoal canister.
The ECM performs occasional leak tests to make sure that the EVAP emission control system is functioning properly when the vehicle is turned off.
During these tests, the ECM shuts off the EVAP system by closing both the vent control valve and the purge control valve to establish a sealed EVAP system. Then, the ECM monitors the pressure in the EVAP system.
The P0446 code is triggered if the EVAP system fails to maintain proper pressure during the leak test, or if the ECM detects a short in the vent control valve activation circuit.
Other Troubleshooting Codes about Evaporative EVAP Emission Control System
Other Troubleshooting Codes about Evaporative EVAP Emission Pressure Sensor
Other Troubleshooting Codes about Evaporative EVAP Emission System Leak
Another Troubleshooting Code about Evaporative EVAP
The problems caused by the P0446 code don't really manifest themselves in drivability issues. However, there are a couple of symptoms that you can notice:
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The P0466 code ranks low on the seriousness scale. The driver probably wouldn't notice any change associated with the P0446 code except for the check engine light going off.
That being said, it's important that you fix the problem as soon as possible, just like any other check light engine DTC.
Here are a few ways to fix the code P0446
James is a certified auto technician specializing in commercial vehicles. With 30 years of experience under his belt, James has encountered almost every type of automotive issue there is! Besides his day job at the repair shop, he is also an amateur race car driver.