P0446 Evaporative Emmission Control System Vent Control Circuit

OBD-II Trouble Code Technical Description

Evaporative Emission Control System Vent Control Circuit Malfunction

What does that mean?

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 Batt. 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

Other EVAP DTCs: P0440 - P0441 - P0442 - P0443 - P0446 - P0453 - P0455 - P0456

Need more help?

If you still need help regarding the P0446 trouble code, please post your question in our auto repair forums.

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