What does it mean?
This diagnostic code (DTC) is a generic OBD-II powertrain code. It is considered generic because it applies to all makes and models of vehicles (1996 and newer), although specific repair steps may vary by model.
The Evap purge valve has only one purpose. It closes to seal the vent so that the EVAP system can pressurize and ensure there are no leaks. The Evap purge valve is typically powered by a 12 V battery voltage with the ignition on.
The ECM driver controls the ground, and when grounded, it 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 be set. The code may also refer to the ECM detecting that the EVAP system is unable to achieve or maintain vacuum during the test.
Symptoms
There will be no obvious symptoms for the driver, other than the illumination of the Malfunction Indicator Lamp (MIL).
Causes
A P0446 code could mean that one or more of the following events have occurred:
Faulty vent valve
Open, short, or excessive resistance in the vent valve control circuit
Obstruction of the purge valve
Faulty PCM
Possible Solutions
With an OBD-II P0446 fault code, here are some things to try:
Replace the vent valve
Repair open, short, or resistance issues in the control circuit
Repair an open, shorted, or resistance issue in the power circuit
Replace PCM
Other EVAP DTCs: P0440 – P0441 – P0442 – P0443 – P0444 – P0445 – P0447 – P0448 – P0449 – P0452 – P0453 – P0455 – P0456