P0446 Subaru Evaporative Emission Vent System Performance

Possible causes

– Plugged vapor canister
– Faulty vent solenoid
– Pinched or blocked EVAP hose
– Faulty FTP sensor

Tech description

Dirt and dust intrusion into the EVAP canister vent hose assembly, resulting in restricted air flow, may cause this condition.

What about the obd code?

The Powertrain Control Module (PCM) sets the P0446 Subaru code if the vacuum decay rate is greater than a predetermined value.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Possible a noticeable fuel odor caused by the release of fuel vapors

P0446 Subaru Description

The Powertrain Control Module (PCM) monitors the performance of the Evaporative Emission (EVAP) system by applying a predetermined level of vacuum to the EVAP system then monitors the vacuum decay rate.