failed evap vent solenoid

Evap vent valve has only one purpose. It closes in order to seal the vent so the EVAP system can pressurize and ensure there are no leaks. Evap vent valve is usually supplied Battery voltage with key on. The ECM's driver controls the ground, and when grounded, activates the valve (closing it). If the ECM detects a short to ground, and open,or a short to battery voltage on the control circuit, P0446 will set. Code also may refer to ECM detecting that EVAP system is unable to achieve or maintain vacuum during test.

Symptoms

There will be no obvious symptoms to driver, other than MIL illumination.

Causes

A code P0446 could mean one or more of the following has happened:

Faulty vent valve

Open, short or excessive resistance on Vent valve control circuit

Blockage of vent valve

Bad PCM

Possible Solutions

With a P0446 OBD-II trouble code, here are some things to try:

Replace Vent valve

Repair open, short, or resistance problem in control circuit

Repair open, or short, or resistance problem in power circuit

Replace PCM

Check the sensor in the engine

Replace the Vsv for the charcoal canister

Look for a disconnectted or damaged hose around the air filter box that goes the evap solenoid