Possible causes

– Faulty canister vent control valve
– Purge Control Valve harness is open or shorted
– Purge Control Valve electrical circuit poor connection

Tech notes

There is a factory service bulletin for the following Nissan models:

2002 Nissan Altima
2003 Nissan Altima
2004 Nissan Altima
2005 Nissan Altima
2002-2005 Nissan Altima Factory Service Bulletin OBDII Code P0447

When is the code detected?

An improper voltage signal is sent to Engine Control Module (ECM) through Evaporative Emission System (EVAP) canister vent control valve.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0447 NISSAN Description

The Evaporative Emission System (EVAP) canister vent control valve is located on the EVAP canister and is used to seal the canister vent. This solenoid (the EVAP canister vent control valve) responds to signals from the Engine Control Module (ECM). When the ECM sends an ON signal, the coil in the solenoid valve is energized.
A plunger will then move to seal the canister vent. The ability to seal the vent is necessary for the on board diagnosis of other evaporative emission control system components.This solenoid valve is used only for diagnosis, and usually remains opened. When the vent is closed, under normal purge conditions, the evaporative emission control system is depressurized and allows EVAP Control System (Small Leak) diagnosis.

NISSAN Technical Service Bulletins for P0447 code