DTC P0446 (VCMSOL_Low): EVAP Emission Control System Vent Control Low Input

NOTE: Impreza 2.2L and Legacy models are equipped with a drain valve which may also be referred to as a vent control solenoid. They perform the same function.

Turn ignition on. Using voltmeter connected to ground, backprobe PCM connector terminal No. 35 (Brown/Yellow wire). If voltage reading is 10 volts or less, go to next step. If voltage reading is more than 10 volts, check for an intermittent problem, as system is normal at this time. Check for poor contact at PCM connector and vent control solenoid connector.
Turn ignition off. Disconnect vent control solenoid connector and PCM connector. Using an ohmmeter, check resistance between vent control solenoid connector terminal No. 2 (Brown/Yellow wire) and ground. If resistance is more than 10 ohms, go to next step. If resistance is 10 ohms or less, check for short in harness between PCM and vent control solenoid connector.
Check resistance of harness between vent control solenoid connector terminal No. 2 and PCM connector terminal No. 35 (Brown/Yellow wire). If resistance is one ohm or less, go to next step. If resistance is more than one ohm, check for an open in harness between PCM and vent control solenoid connector.
Turn ignition off. Measure resistance of vent control solenoid between terminals No. 1 and 2. If resistance is 10-100 ohms, go to next step. If resistance is less than 10 ohms or more than 100 ohms, replace vent control solenoid.
Turn ignition on. Using voltmeter connected to ground, measure voltage at vent control solenoid connector terminal No. 1 (Yellow/Green wire on Forester and Impreza, or Yellow/Blue wire on Legacy). If voltage is more than 10 volts, check for poor connection at vent control solenoid connector. If voltage reading is 10 volts or less, check for an open in harness between main relay and vent control solenoid connector. If okay, check for poor contact at main relay connector.