Possible causes

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

Tech notes

Very common problem with Nissan vehicles. Before replacing any parts, check for damage EVAP canister and for loose hoses from the vent control valve to the canister.

There are factory service bulletins for the following Nissan models:

2005-2007 Nissan Pathfinder
2005-2007 Nissan Pathfinder Factory Service Bulletin OBDII Code P0448

2007-2009 Nissan Altima Sedan
2008-2009 Nissan Altima Coupe
2007-2009 Nissan Altima Hybrid
2009 Nissan Maxima
Nissan Factory Service Bulletin OBDII Code P0448

When is the code detected?

EVAP canister vent control valve remains closed under specified driving conditions.

Symptoms

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

P0448 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 componentsThis 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 P0448 code